Ceramic Engineering and Science Proceedings, Volume 38, Issue 3, 2017

A Collection of Papers Presented at the 41st International Conference on
Advanced Ceramics and Composites January
22–27, 2017, Daytona Beach, Florida

Edited by

Waltraud M. Kriven
Narottam P. Bansal
Mihails Kusnezoff
Tatsuki Ohji
Yanchun Zhou
Kyoung Il Moon
Josef Matyáš
Kiyoshi Shimamura
Soshu Kirihara

Volume Editors

Surojit Gupta
Jingyang Wang

This edition first published 2018
© 2018 The American Ceramic Society

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ISBN: 9781119474692

ISSN: 0196-6219

Cover design by Wiley

CONTENTS

INTRODUCTION

SOLID OXIDE FUEL CELLS

MITIGATION OF COMPRESSOR STALL/SURGE IN A HYBRID SOLID OXIDE FUEL CELL-GAS TURBINE SYSTEM
1. INTRODUCTION
2. TURBOMACHINERY MODELING
3. RESULTS AND DISCUSSION
4. CONCLUSION
5. ACKNOWLEDGEMENTS
6. REFERENCES
CHARACTERISTICS OF PROTECTIVE SPINEL MANGANESE COBALTITE COATINGS PRODUCED BY APS FOR Cr-CONTAINED SOFC INTERCONNECTS
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSION
5. REFERENCES
INFLUENCE OF TEMPERATURE AND STEAM CONTENT ON DEGRADATION OF METALLIC INTERCONNECTS IN REDUCING ATMOSPHERE
1. 1. INTRODUCTION
2. 2. METHODS & EXPERIMENTALS
3. 3. RESULTS & DISCUSSION
4. 4. CONCLUSIONS
5. 5. ACKNOWLEDGEMENTS
6. REFERENCES
FABRICATION OF THE ANODE-SUPPORTED SOLID OXIDE FUEL CELL WITH DIRECT PORE CHANNEL IN THE CERMET STRUCTURE TO IMPROVE THE ELECTROCHEMICAL PERFORMANCE
1. INTRODUCTION
2. EXPERIMENTAL DETAILS
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. REFERENCES
CRITICAL EVALUATION OF DYNAMIC REVERSIBLE CHEMICAL ENERGY STORAGE WITH HIGH TEMPERATURE ELECTROLYSIS
1. BACKGROUND
2. EXPERIMENTAL
3. MODEL
4. CONCLUSIONS
5. REFERENCES
ESTIMATION OF POLARIZATION LOSS DUE TO CHROMIUM POISONING OF LSM-BASED CATHODES IN SOLID OXIDE FUEL CELLS
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. ACKNOWLEDGMENTS
6. REFERENCES

ADVANCED PROCESSING AND MANUFACTURING TECHNOLOGIES

SYNTHESIS AND TRIBOLOGICAL BEHAVIOR OF Bi-Cr₂AlC COMPOSITES
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. ACKNOWLEDGEMENTS
6. REFERENCES
FINITE ELEMENT ANALYSIS OF SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS (SHS) OF SILICON NITRIDE
1. INTRODUCTION
2. EXPERIMENTAL
3. ADIABATIC TEMPERATURE CALCULATIONS
4. FINITE ELEMENT ANALYSIS MATHEMATICAL MODEL
5. RESULTS AND DISCUSSION
6. CONCLUSIONS
7. ACKNOWLEDGMENT
8. NOMENCLATURE
9. REFERENCES
TEM ANALYSIS OF DIFFUSION-BONDED SILICON CARBIDE CERAMICS JOINED USING METALLIC INTERLAYERS
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. ACKNOWLEDGEMENTS
6. REFERENCES
NUMERICAL ANALYSIS OF INHOMOGENEOUS BEHAVIOR IN FRICTION STIR PROCESSING BY USING A NEW COUPLED METHOD OF MPS AND FEM
1. INTRODUCTION
2. METHOD FOR ANALYSIS
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. REFERENCES

ADVANCED MATERIALS AND INNOVATIVE PROCESSING IDEAS FOR THE INDUSTRIAL ROOT TECHNOLOGY

STUDY OF SHIELDING METHOD TO REDUCE LEAKAGE MAGNETIC FIELDS OF AN OPENING IN A MAGNETICALLY SHIELDED ROOM
1. INTRODUCTION
2. ANALYTICAL MODEL AND ANALYSIS METHOD
3. ANALYSIS RESULTS
4. CONSIDERATION OF ANALYSIS RESULTS
5. EXPERIMENTAL METHOD
6. EXPERIMENTAL RESULT
7. CONCLUSIONS
8. REFERENCE

MATERIALS FOR EXTREME ENVIRONMENTS

LOW-TEMPERATURE SYNTHESIS OF HAFNIUM DIBORIDE POWDER VIA MAGNESIOTHERMIC REDUCTION IN MOLTEN SALT
1. INTRODUCTION
2. EXPERIMENTAL PROCEDURES
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. REFERENCES
TRIBOLOGY STUDY OF NOVEL Ti₃SiC₂ MATRIX COMPOSITES REINFORCED WITH CERAMICS (Al₂O₃, BN, B₄C) PARTICULATES
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. ACKNOWLEDGEMENTS
6. REFERENCES

ADVANCED MATERIALS FOR SUSTAINABLE NUCLEAR FISSION AND FUSION ENERGY

INTERFACIAL REACTION AND MECHANICAL PROPERTIES OF SiC BONDED WITH ZIRCALOY-4 USING Ni, Zr/Al DOUBLE INTERLAYERS
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. ACKNOWLEDGMENTS
6. REFERENCES

SINGLE CRYSTALLINE MATERIALS FOR ELECTRICAL, OPTICAL, AND MEDICAL APPLICATIONS

CHARACTERIZATION APPROACHES OF FEMTOSECOND DIRECT LASER WRITING (DLW) MODIFICATIONS INSIDE CUBIC YAG CRYSTALS
1. INTRODUCTION
2. SAMPLE PREPARATION
3. GUIDING PROPERTIES
4. GAIN MEASUREMENTS
5. CONCLUSION AND PERSPECTIVES
6. ACKNOWLEDGEMENTS
7. REFERENCES

ADDITIVE MANUFACTURING AND 3D PRINTING TECHNOLOGIES

COMPARISON OF DYNAMIC MASK- AND VECTOR-BASED CERAMIC STEREOLITHOGRAPHY
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSION
5. ACKNOWLEDGEMENTS
6. REFERENCES
ADDITIVE MANUFACTURING (3D PRINTING) OF CERAMICS: MICROSTRUCTURE, PROPERTIES, AND PRODUCT EXAMPLES
1. INTRODUCTION
2. LIMITATIONS OF ADDITIVE MANUFACTURING
3. CONVENTIONAL CERAMIC COMPONENT MANUFACTURING BY REACTION BONDING (RB)
4. 3D PRINTED RB SiC FABRICATION AND CHARACTERIZATION
5. MICROSTRUCTURE AND MECHANICAL PROPERTIES
6. PRODUCT EXAMPLES
7. SUMMARY
8. REFERENCES

GEOPOLYMERS, CHEMICALLY BONDED CERAMICS, ECO-FRIENDLY, AND SUSTAINABLE MATERIALS

IMPACT OF VARIOUS ALUMINOSILICATE COMPOUNDS IN GEOPOLYMER FOAM FORMATION TO A SI/M=0.7 OF SILICATE SOLUTION
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS
4. CONCLUSION
5. REFERENCES
GEOPOLYMERS BASED ON NATURAL AND SYNTHETIC METAKAOLIN A CRITICAL REVIEW
1. INTRODUCTION
2. GEOPOLYMERS BASED ON NATURAL METAKAOLIN MK-750
3. GEOPOLYMERS BASED ON SYNTHETIC METAKAOLIN SMK-750
4. REFERENCES
ON THE DURABILITY BEHAVIOR OF NATURAL FIBER REINFORCED GEOPOLYMERS
1. INTRODUCTION
2. EXPERIMENTAL PROGRAM
3. TESTING METHODS
4. RESULTS AND DISCUSSION
5. CONCLUSIONS
6. REFERENCES
PERFORMANCE AND DURABILITY OF Fe-RICH INORGANIC POLYMER COMPOSITES WITH BASALT FIBERS
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSIONS
5. ACKNOWLEDGEMENTS
6. REFERENCES
WETTING ANGLE: NEW PARAMETER INDICATING THE REACTIVITY OF ALKALINE SOLUTIONS AND GEOPOLYMER BINDERS
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. CONCLUSION
5. REFERENCES
EFFECT OF TiO₂ AND ZnO NANOPOWDERS ON METAKAOLIN-SODIUM HYDROXIDE GEOPOLYMERS
1. INTRODUCTION
2. EXPERIMENTAL METHODS
3. RESULTS AND DISCUSSION
4. SUMMARY AND CONCLUSIONS
5. ACKNOWLEDGEMENTS
6. REFERENCES
ECO-FRIENDLY GEOPOLYMER COMPOSITE FOR WINTER SEASON PAVEMENT POTHOLE PATCHING
1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSION
4. Factorial Analysis
5. CONCLUSIONS
6. ACKNOWLEDGEMENTS
7. REFERENCES

EULA

List of Tables

Chapter 2

Table 2.1

Chapter 3

Table 3.1
Table 3.2
Table 3.3

Chapter 5

Table 5.1
Table 5.2

Chapter 6

Table 6.1

Chapter 10

Table 10.1
Table 10.2

Chapter 14

Table 1
Table 2
Table 3

Chapter 15

Table 1

Chapter 16

Table 1
Table 2

Chapter 18

Table I
Table II
Table III

Chapter 20

Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9

Chapter 21

Table I
Table II
Table III

Chapter 22

Table I
Table II

Chapter 23

Table I
Table II
Table III

Chapter 24

Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7

List of Illustrations

Chapter 1

Figure 1: Pressure reduction and stall/surge mitigation of 1.7 MW multi-stage compressor based on controlled stall/surge assuming a connecting pipe between the compressor outlet and inlet that keeps the compressor mass flow rate at a constant rate.
Figure 2: Air mass flow rae incease at the front impeller inlet due to the reduced back pressure on the compressor.
Figure 3: Compressor air mass flow rate increase post stall/surge to the normal design value of 7 kg/s.

Chapter 2

Figure 1: (a) Schematic diagram of the APS system. (b) Re-granulated CMC powders.
Figure 2: The XRD results of (a) annealed CMC powders with different heating temperature; (b) CMC coated samples after the heat treatment of 800oC for 4,343 hrs.
Figure 3: (a) Surface morphology of as sprayed CMC coatings on Crofer 22H and (b) EDS results obtained from the red square area in (a).
Figure 4: Micrographs in (a) low and (b) high magnifications of the sprayed CMC coating on a Crofer 22 H substrate and after the heat treatment at 800oC for 12 hours.
Figure 5: Surface morphology and its EDS analysis results of CMC/22H specimen after long-term durability test at 800oC for 4,343 hours in air.
Figure 6: Cross-sectional micrographs and its element distribution images obtained from EDS analysis of (a) CMC/22H; (b) CMC/APU and (c) CMC/SS441 specimens after long-term durability test at 800oC for 4,343 hours in air.
Figure 7: Arrhenius plots of CMC-coated Crofer 22 H, Crofer 22 APU and SS441 specimens.
Figure 8: Long-term ASR measurement results of CMC- and LSM-coated Crofer22H, Crofer 22APU and SS441 specimens.

Chapter 3

Figure 1: MIC sample layout for resistivity measurements in dual gas atmosphere: Green marked areas symbolize Ni-coated sections. Sealing from the outer environment was enforced with a special glass frame (yellow). Electrical contact between the upper and the lower steel samples was made with a nickel net interconnection.
Figure 2: Mass- and thickness development over 1000 h oxidation in reducing atmosphere (FG1 = N₂/H₂ = 80/20 vol. % + 3 % H2O (H₂/H₂O = 87/13 vol. %)) for Crofer 22 APU in the temperature range 725°C (at the top left) to 875°C (bottom right). The results for the thickness development were gained from the analysis of microsections of blank samples.
Figure 3: Mass- and thickness development over 1000 h oxidation in reducing atmosphere (FG1 = N₂/H₂ = 80/20 vol. % + 3 % H₂O (H₂/H₂O = 87/13 vol. %)) for Crofer 22 H in the temperature range 725°C (at the top left) to 875°C (bottom right). The results for the thickness development were gained from the analysis of microsections of blank samples.
Figure 4: Mass- and thickness development over 1000 h oxidation in reducing atmosphere (FG1 = N₂/H₂ = 80/20 vol. % + 3 % H₂O (H₂/H₂O = 87/13 vol. %)) for AISI 441 in the temperature range 725°C (at the top left) to 875°C (bottom right). The results for the thickness development were gained from the analysis of microsections of blank samples.
Figure 5: Comparison of mass- (left) and thickness (right) development of the blank samples after 1000 h oxidation period in reducing atmosphere (FG1 = N₂/H₂ = 80/20 vol. % + 3 % H₂O (H₂/H₂O = 87/13 vol. %)) for tested ferritic alloys in the temperature range 725°C - 875°C.
Figure 6: (Left) Squared mass gain for AISI 441 at 725°C in reducing atmosphere (FG1 = N₂/H₂ = 80/20 vol. % + 3 % H₂O (H₂/H₂O = 87/13 vol. %)). Linear growth behavior with R² = 0,996 was found. (Right) Results for the logarithmized kp,w values which were calculated out of the slope of the squared mass development graphs of the blank samples(s. Figure 2 to Figure 4).
Figure 7: Element distribution detected by EDS-mapping in Crofer 22 APU samples after 1000 h oxidation period at 875°C in reducing atmosphere (FG1 = N2/H2 = 80/20 vol. % + 3 % H2O (H2/H2O = 87/13 vol. %)). An area of 57 × 45 μm was analyzed.
Figure 8: Element distribution detected by EDS-mapping in Crofer 22 H after 1000 h oxidation period at 875°C in reducing atmosphere (FG1 = N₂/H₂ = 80/20 vol. % + 3 % H₂O (H₂/H₂O=87/13 vol. %)). An area of 38 μm × 30 μm was analyzed.
Figure 9: Overlay of added element distribution for O, Si and Nb (left, A) and superposition of Si with O (right, B). Laves phases are present at positions in which Si is dissolved in Nb (marked areas in A). SiO2 is located at the interface between the outer oxide scale and the bulk of material (marked areas in B).
Figure 10: Element distribution detected by EDS-mapping in AISI 441 after 1000 h oxidation period at 875°C in reducing atmosphere (FG1 = N2/H2 = 80/20 vol. % + 3 % H2O (H2/H2O = 87/13 vol. %)). An area of 38 μm × 30 μm was analyzed. Cr2O3 and spinel are clearly separated from each other. Also TiO2, SiO2 and Al/Al2O3 can be found in the inner oxidation zone (for comparison, see Figure 11).
Figure 11: Overlay of implemented element distribution for Si with O (left, A), Si with Nb (B), Ti with O (C) and Al with O (right, D). SiO2 is located at the interface to the outer oxide scale. Laves phases are present at positions in which Si is dissolved in Nb (violet spots in B). TiO2 is located at reddish positions illustrated in C. Also some Al/Al2O3 can be found in D.
Figure 12: (Left) Schematic representation of the methodology of data analysis of the inner oxidation zone by linear analysis. Ten single images (measuring field: 76 μm × 57 μm) were segmented vertically into 15 chords. The length of the extension of the inner oxidation zone was measured in succession (distance from inner oxidation zone to the outer oxide layer). (Right) Results of linear analysis of the inner oxidation zone for the three tested ferritic steels after 1000 h oxidation in reducing atmosphere (FG1 = N2/H2 = 80/20 vol. % + 3 % H2O (H2/H2O = 87/13 vol. %) in the temperature range 725°C – 875°C.
Figure 13: Comparison of the oxide scale thickness (left) and mass gain (right) after 1000 h oxidation for two different fuel gas compositions FG1 = N2/H2 = 80/20 vol. % + 3 % H2O (H2/H2O = 87/13 vol. %), FG2 = H2/H2O = 50/50 vol. % (shaded bars).
Figure 14: ASR development over 1000 h oxidation period in dual gas atmosphere. Inside the sealed test samples: a reducing atmosphere with FG2 = H2/H2O = 50/50 vol. % was induced.
Figure 15: Comparison of the outer oxidation zone from artificially grown oxides on Crofer 22 APU with oxide thickness data of SOFC stacks measured at different stack layer positions. The stacks were operated over 2000 h (B), 3300 h (C) and 5000 h (D). The oxide thickness data was compared with oxide thickness data of artificially oxidized MIC samples interpolated to the operation time of the stacks, which is schematically illustrated in (A).

Chapter 4

Figure 1: The approach for anode pore array perforation of tape-casted green tapes: (a) anode green tape fabrication, (b) pore array anode structure, (c) laminating layers of the anode green tape that include perforated and non-perforated anode green tape to form an anode supported substrate, (d) electrolyte layer built on an abrasive and polished surface of the anode electrode, and (e) fabrication of a cathode electrode.
Figure 2: SEM cross-section micrograph (a) lower magnification 250 x, (b) higher magnification 1800 x.
Figure 3: Cell voltage and power density as a function of current density for the 5 x 5 cm² cell w/ and w/o green tape perforation.
Figure 4: The EIS impedance plots for the 5 x 5 cm² cell w/ and w/o green tape perforation at 800 °C and OCV condition (zero current loading).
Figure 5: The plots of cell potencial, temperature, current density, and power density vs. time for the 5ₓ 5 cm² cell w/ green tape perforation
Figure 6: The surface morphology for the post laser perforation hole observation by (a) top image and (b) Multifocus image by Leica DVM6 A Digital Microscope; (c) SEM image.
Figure 7: Cell voltage and power density as a function of current density for the 10 x 10 cm² cell (a) w/o laser perforation, (b) w/ laser perforation.

Chapter 5

Figure 1: Configuration for reversible solid oxide system
Figure 2: Test stand flow configuration
Figure 3: Fuel cell V-j performance at conditions listed in Table 5.1
Figure 4: Electrolysis V-j performance at conditions listed in Table 5.2
Figure 5: Microgrid power demand plotted with RSOFC power output
Figure 6: Solar PV power input to the RSOFC for hydrogen production
Figure 7: Hydrogen production by electrolysis of the same system with 50 kW maximum power input

Chapter 6

Figure 1: Cell test results of the cell (a) under open circuit condition, and (b) under 0.5 A/cm² constant cathodic current condition.
Figure 2: Cathodic electrode polarization of Cell B before and after Cr-poisoning as a function of current density.
Figure 3: SEM micrographs of cathode cross sections in cell (a) tested under open circuit condition, and (b) tested under 0.5 A/cm₂ cathodic current condition.

Chapter 7

Figure 1: SE SEM images of polished, (a) Bi-10%Cr₂AlC, (b) Bi-20%Cr₂AlC, and (c) Bi-30%Cr₂AlC surfaces.
Figure 2: Plot of, (a) hardness, and (b) porosity versus MAX content.
Figure 3: Plot of, (a) compressive stress versus displacement, and (b) yield strength versus MAX phase content of different Bi-MAX composites.
Figure 4: Plot of, (a) friction coefficient, and (b) wear rate versus MAX phase additions.
Figure 5: SEM SE micrographs of, (a) Bi-20%Cr₂AlC, (b) alumina surface, and (c) BSE image of the same region after tribological testing.

Chapter 8

Figure 1: Reaction mechanism proposed for SHS of silicon nitride.
Figure 2: Model geometry sketches of the reaction system.
Figure 3: The change of the adiabatic temperature when different amounts of reactants are used in the reactant pellet.
Figure 4: The temperature and composition distributions of species at the center line of the pellet at 25 seconds after the ignition. Reactant composition is 3 Si + 4/3 NaN₃ + 0.2 Si₃N₄ and the ignition heat flux = 5 × 10⁷ W/m², ignition time = 5 s, φ = 0.7, pellet diameter = 25.4 mm, and pellet length = 127 mm.
Figure 5: The velocity of reaction front movement along the length of the pellet. Reactant composition is 3 Si + 4/3 NaN₃ + 0.2 Si₃N₄ and the ignition heat flux = 5 × 10⁷ W/m², ignition time = 5 s, φ = 0.7, pellet diameter = 25.4 mm, and pellet length = 127 mm.
Figure 6: The change of maximum temperature at the midpoint of the pellet (x = 63.5 mm) when different pellet diameters are used. Reactant composition is 3 Si + 4/3 NaN₃ + 0.2 Si₃N₄ and the ignition heat flux = 5 × 10⁷ W/m², ignition time = 5 s, φ = 0.7, (12.7, 25.4 and 50.8 mm), and pellet length = 127 mm.
Figure 7: Change of maximum temperature at the midpoint of pellet (x = 63.5 mm) when different heat flux is used. Reactant composition is 3 Si + 4/3 NaN₃ + 0.2 Si₃N₄ and the ignition heat flux = (5 × 10⁶, 1 × 10⁷, 5 × 10⁷ W/m²), ignition time = 5 s, φ = 0.7, pellet diameter = 25.4 mm, and pellet length = 127 mm.
Figure 8: The change of maximum temperature at the midpoint of pellet (x = 63.5 mm) when different ignition times are used. Reactant composition is 3 Si + 4/3 NaN₃ + 0.2 Si₃N₄ and the ignition heat flux = 5 × 10⁷ W/m², ignition time = (1, 2, 3, 4 and 5 s), φ = 0.7, pellet diameter = 25.4 mm, and pellet length = 127 mm.
Figure 9: The change of maximum temperature at the midpoint of pellet (x = 63.5 mm) when different amounts of silicon nitride diluents are used. Reactant composition is 3 Si + 4/3 NaN3 + z Si3N (z = 0, 0.1, 0.2 and 0.3) and the ignition heat flux = 5X 10⁷ W/m², ignition time = 5 s, (]) = 0.7, pellet diameter = 25.4 mm, and pellet length = 127 mm.
Figure 10: The change of maximum temperature at the midpoint of pellet (x = 63.5 mm) when different green densities are used. Reactant composition is 3 Si + 4/3 NaN₃ + 0.2 Si₃N₄ and the ignition heat flux = 5 × 10⁷ W/m2, ignition time = 5 s, φ = (1, 0.8, 0.75, 0.7 and 0.5), pellet diameter = 25.4 mm, and pellet length = 127 mm.

Chapter 9

Figure 9.1 Scanning ion microscope (SIM) images of the diffusion bond obtained with the FIB. (a) Cross-sectional image and (b) image of the area where the thin sample was fabricated.
Figure 9.2 STEM images of diffusion bond: (a) SE STEM mode, (b) BF STEM mode, and (c) HAADF STEM mode.
Figure 9.3 HAADF-STEM image of the reaction layer and elemental mapping images obtained by STEM-EDS.
Figure 9.4 (a, b) TEM micrographs and (b, c) SAD patterns obtained from grains (1) and (2).
Figure 9.5 (a) TEM micrograph and (b, c) SAD patterns obtained from Cu-Si matrix region.
Figure 9.6 Change in the microstructure of interface of SA-THX/Ti/Cu/Ti/SA-THX (a) before processing, (b) at maximum temperature (1200°C), (c) in cooling, and (d) after processing

Chapter 10

Figure 10.1 Schematic illustration of specimen for FSW and position of thermocouple.
Figure 10.2 Schematic illustration of model for MPS method.
Figure 10.3 Finite element model for finite element analysis.
Figure 10.4 Heat and heat density distributions on specimen top surface. (a) Head distribution (MPS) (b) Head density distribution (FEM)
Figure 10.5 Maximum temperature distributions on central top and bottom surface transverse to joining line.
Figure 10.6 Boundary temperature effect of plastic strain distributions along joining line at central view transverse to joining line.
Figure 10.7 Influence of boundary temperature on plastic strain distributions along joining line at central view transverse to joining line

Chapter 11

Figure 11.1 The model of he MSR.
Figure 11.2 Partition plate lengths examined in this study.
Figure 11.3 The number of divisions of the partition plates.
Figure 11.4 Comparison of the magnetic flux density along the x axis from an opening for partition plates with 4 partitions and various lengths.
Figure 11.5 Comparison of the magnetic flux density along the x axis from an opening for partition plates with 9 partitions and various lengths.
Figure 11.6 Comparison of the magnetic flux density along the x axis from an opening for partition plates with 16 partitions and various lengths
Figure 11.7 Magnetic flux density with distance along the y axis for plates with 4 partitions.
Figure 11.8 Magnetic flux density with distance along the y axis for plates with 9 partitions.
Figure 11.9 Magnetic flux density with distance along the y axis for plates with 16 partitions.
Figure 11.10 Magnetic flux density on the y axis for plates with 9 partitions
Figure 11.11 Distribution of magnetic flux density on the y axis: comparison of the vector distributions for 4-partition plates of four lengths.
Figure 11.12 Distribution of magnetic flux density on the y axis: comparison of the vector distributions for 16-partition plates of four lengths.
Figure 11.13 Comparison of the best magnetic flux attenuation performance along the x axis for each number of partitions.
Figure 11.14 Comparison of the best magnetic flux attenuation performance on the y axis for each number of partitions.
Figure 11.15 The measurement system used in the experiment.\
Figure 11.16 Duct dimensions.
Figure 11.17 Measurement coordinate scheme.
Figure 11.18 The magnetic flux density versus distance from an opening on the x axis: comparison of analytical and experimental data.
Figure 11.19 The magnetic flux density versus distance from an opening on the y axis: comparison of analytical and experimental data.

Chapter 12

Figure 1: XRD patterns of samples of stoichiometric composition, after 4 h heating at 850°C in: a) NaCl, b) KCl, and c) MgCl₂, respectively.
Figure 2: XRD patterns of samples of stoichiometric composition, after 4 h heating in MgCl₂ at: a) 750, b) 850, c) 950, and d) 1000°C, respectively.
Figure 3: XRD patterns of samples after 4 h heating at 1000°C in MgCl₂ using: a) 0, b) 20, and c) 80 wt% excessive Mg, respectively.
Figure 4: XRD patterns of samples resultant from 4 h heating in MgCl₂ at 1000°C, using 80 wt% excessive Mg and respectively: a) 0, b) 10, and c) 20 wt% excessive B₂O₃.
Figure 5: XRD patterns of samples resultant from heating the batch powders containing respectively 80 and 20 wt% excessive Mg and B₂O₃ in MgCl₂ at 950°C for a) 4, b) 6, and c) 8 h, respectively.
Figure 6: XRD patterns of samples resultant from 6 h heating in MgCl₂ at 950°C, using 80 wt% excessive Mg and a) 20, b) 40, and c) 60 wt% excessive B₂O₃, respectively.
Figure 7: XRD patterns of product samples resultant from, a) 6 h heating at 950°C using respectively 80 and 60 wt% excessive Mg and B₂O₃, and b) 4 h at 1000°C using respectively 80 and 20 wt% excessive Mg and B₂O₃ (after water washing and subsequent acid leaching).
Figure 8: SEM/TEM images and EDS of the HfB₂ product powders whose XRD patterns are shown in Figure 7 (a, c and e) 6 h at 950°C and (b, d and f) 4 h at 1000°C.
Figure 9: SEM images of a) as-received HfO₂ powder and b) Hf prepared via magnesiothermic reduction of HfO₂ (Reaction (3)) in MgCl₂ at 950°C for 6 h.

Chapter 13

Figure 1: FESEM SE micrographs of, (a) sintered Ti₃SiC₂, (b) BSE image of the same region, (c) 312Si-1%Al₂O₃, (d) BSE image of the same region, (e) 312Si-6%Al₂O₃, and (f) BSE image of the same region.
Figure 2: FESEM SE micrographs of, (a) 312Si-1%B4C, (b) BSE image of the same region, (c) 312Si-5%B4C, and (d) BSE image of the same region.
Figure 3: FESEM SE micrographs of, (a) 312Si-1%BN, (b) BSE image of the same region, (c) 312Si-5%BN, and (d) BSE image of the same region.
Figure 4: XRD patterns of, (a) Ti₃SiC₂-Al₂O₃ composites, (b) Ti₃SiC₂- B₄C composites, and (c) Ti₃SiC₂-BN composites.
Figure 5: Plot of, (a) relative density, and (b) hardness versus the vol (%) additions of ceramics particulates.
Figure 6: Plot of friction coefficient versus distance of, (a) Ti₃SiC₂-1wt%Ni, (b) 312Si-1%Al₂O₃,(c) 312Si-1%B4C and (d) 312Si-1%BN.
Figure 7: Plot of friction coefficient (μ) versus distance of, (a) 312Si-6%Al₂O₃, (b) 312Si-5%B₄C, (c) 312Si-5%BN, and (d) Transition Distance (TD) versus additives (vol%).
Figure 8: BSE SEM micrographs of, (a) stainless, and (b) 312Si-5%BN surface after tribological testing.

Chapter 14

Figure 1: a schematic graph for assembling of α-SiC/Ni or Zircaloy-4/Al/Zircaloy-4 joints.
Figure 2: XRD patterns of (a) pristine Ni powder; (b) pristine SiC powder; and (50wt.%) Ni/β-SiC composites heat-treated at various temperatures: (b) 600 °C and (d) 1000 °C.
Figure 3: An optical image of (a) pristine polished SiC; and fracture surface of the Ni/6H-SiC diffusion couples after heat-treatment at various temperatures: (b) 600 °C for 10h; and (c) 1000 °C for 0.5h.
Figure 4: Cross-section SEM micrographs of Ni/SiC diffusion couples annealed at 1000°C for 0.5h: (a) general view; and (b) interfacial reaction zone, the inset image is an enlarged view of the red rectangular area, and points 1-3 corresponds to the chemical composition analysis position by EDS.
Figure 5: A SEM micrographs and EDS linescans taken from the cross section of zircaloy-4/Al/ zircaloy-4 joints annealed at 600°C for 10 hours: (a) overview; and (b) Al and Zr composition profiles across the zircaloy-4/Al/ zircaloy-4 joint corresponding to Fig. 5(a).
Figure 6: XRD patterns of (a) pristine β-SiC powder; (b) pristine α-Zr powder; and (50wt.%) Zr/ β-SiC composites heat-treated at various temperatures for 4h: (c) 600 °C; (d) 800 °C; (e) 1000 °C; (f) 1200 °C; and (g) 1400 °C.
Figure 7: SEM micrographs in BSE mode and EDS linescans taken from zircaloy-4 alloy/α- SiC joints in cross section annealed at various temperatures for 4 hours: (a)(b)(c) 600 °C and (d)(e)(f) 800°C; Fig. 7(b)and (e) are an enlarged view of the red rectangular area in Fig. 7(a) and (d).
Figure 8: SEM micrographs in BSE mode and EDS linescans taken from zircaloy-4 alloy/α-SiC joints in cross section annealed at various temperatures for 4 hours: (a)(b)(c) 1000 °C and (d)(e)(f) 1200°C; Fig. 8(b)and (e) are an enlarged view of the red or blue rectangular area in Fig. 8(a) and (d).
Figure 9: SEM micrographs in BSE mode and EDS linescans taken from zircaloy-4 alloy/α-SiC joints in cross section annealed at 1400 °C for 4 hours: (a) overview; (b) an enlarged view of reaction zone (I) in Fig. 8(b); (c) an enlarged view of the purple rectangular area in Fig. 8(b); and (d) chemical composition profiles measured by EDS.
Figure 10: (a) Vickers hardness in different regions, and SEM images of Vickers indent impressions in interfacial reaction region of the zircaloy-4 /SiC joints annealing at different temperatures: (b) 1200°C and (c) 1400°C.

Chapter 15

Figure 1: Schematic drawing of the laser beam for DLW on the Nd: YAG crystal.
Figure 2: Schematic view seen from the top (a) and from the side (b) of the DLW structured Nd:YAG crystal.
Figure 3: Images of the beam profile of the guided modes in the 25 μm double tracks (upper row) and in the 20 μm double tracks (lower row) taken with a CCD camera, respectively.
Figure 4: Transmitted output power of the waveguide as a function of the rotation angle of the halfwave-plate.
Figure 5: Single-pass gain as a function of injected pump power for the three different waveguide channel series and bulk propagation in comparison; the injected seed power at 1064 nm was P_seed = 0.07 mW.

Chapter 16

Figure 1: (a) DLP-based system with circular coating system and tiltable vat; (b) Circular structure printed on the DLP-based machine using unfilled photopolymer; the contours clearly show the pixels of the light engine; (c) Structure showing the pixel size of a DLP machine with 80 μm optics
Figure 2: (a) Vector-based laser system with linear coater and tiltable vat, (b) Circular structure printed with laser-based machine using unfilled photopolymer; (c) Structure showing a hatching distance of 20 μm
Figure 3: Recoating system developed and used for the stereolithography systems at TU Wien; (a) View of the whole system, showing the coater, material vat and clamping frame; (b) section view of the two parallel doctor blades
Figure 4: Two different hatching strategies used in this study
Figure 5: (a) CAD-drawing of the test structure which was printed with (b) DLP and (c) laser.
Figure 6: Side part of the test structure showing cavities and pillar structures of different diameters (50–250 μm) printed with (a) DLP and (b) laser
Figure 7: (a) Molar brigde printed with DLP out of ZrO₂, showing the part after debinding (left and after sintering (right); (b) Bone structure printed with DLP out of TCP after sintering

Chapter 17

Figure 1: Various additive manufacturing processes per the ASTM classification^1–3.
Figure 2: A schematic of conventional RB SiC component fabrication at M Cubed²²
Figure 3: Examples of components made by conventional reaction bonding at M Cubed.
Figure 4: Microstructures of RB SiCs made by 3D printing using monomodal SiC particles and comparison with microstructure of RB SiC made by the conventional approach (bimodal SiC particles). Darker particles are SiC, lighter phase is Si.
Figure 5: Microstructures of RB SiCs made by 3D printing using bimodal SiC particles and comparison with microstructure of RB SiC made by the conventional approach (bimodal SiC particles). Darker particles are SiC, lighter phase is Si.
Figure 6: Density and elastic modulus of 3d Printed RB SiC (monomodal and bimodal SiC) as a function of SiC content.
Figure 7: Flexural strength and fracture toughness of 3D printed RB SiC (monomodal and bimodal SiC) as a function of SiC content.
Figure 8: Example of products of various shapes and complexities fabricated by 3D Printing
Figure 9: Lightweighted 10” (250 mm) flat mirror substrate fabricated by 3D Printing - Left: As printed preform, Right: Reaction bonded back and front (ground).
Figure 10: Lightweighted 10" (250 mm) spherical mirror substrate fabricated by 3D Printing and reaction bonding. Curvature of the front face is apparent in the photo on the left.

Chapter 18

Figure 1: Synthesis protocol of geopolymer silica fume foam samples
Figure 2: Evolution of the volume expansion value versus the chemical composition (n_si/(n_Ai+n_M)) of the different foams based on ■ S_kk, □ S_KNa, ▲ S_NaNa and ∆ S_NaK solutions
Figure 3: Pores size distribution of geopolymer foams (a) S_M1 and (b) S_M11 (■ S_KK, □ S_KNa, ■ S_NaNa and S_NaK)
Figure 4: Evolution of the thermal conductivity value versus the porosity rate Xp for samples based on ■ S_kk, □ S_KNa, ▲ S_NaNa and ∆ S_NaK solutions
Figure 5: Thermal conductivity variation versus the chemical composition of the synthetized foams based on ■ S_KK, □ S_KNa, ▲ S_NaNa and ∆ S_NaK solutions

Chapter 20

Figure 1 Particle size distribution curves.
Figure 2 (a) Schematic drawing of the acrylic mold and (b) composite manufacturing process.
Figure 3 Setup for: (a) compression tests; and (b) tensile tests.
Figure 4 Setup for three-point bending tests.
Figure 5 DRX of: a) silica fume, b) metakaolin, and c) blast furnace slag.
Figure 6 DRX of: (a) F3.0-100MK, (b) F3.9-80MK20SF, and (c) F3.9-60MK40BFS.
Figure 7 Compressive Stress x Strain curves of F3.0-100MK, F3.9-80MK20SF, and F3.9-60MK40BFS.
Figure 8 Tensile Stress x Strain curves of the F3.0-100MK, F3.9-80MK20SF, and F3.9-60MK40BFS.
Figure 9 Composites submitted to tensile tests showing different patterns of cracking.
Figure 10 Flexural Strength x Deflection curves of the F3.0-100MK and F3.9-60MK40BFS composites.
Figure 11 Flexural Strength x Deflection curves of the F3.0-100MK and F3.9-60MK40BFS composites before and after being subjected to 15 cycles of wetting and drying.

Chapter 21

Figure 1 Fibers after dissolution test. Left to right: 1 hour, 1 day, 1 week. Top to bottom: glass, carbon, basalt fibers.
Figure 2 Electron microscopy image of basalt fibers exposed for 1 week (left) and the mass loss of basalt fibers during the dissolution test.
Figure 3 Tensile strength of single basalt fiber before and after 1 week of exposure to the alkaline solution.
Figure 4 3-point flexural strength of fiber reinforced inorganic polymers with different processing conditions. The virgin strength without fibers is added.
Figure 5 3-point flexural strength of fiber reinforced inorganic polymers with different activating solutions after 7 and 28 days at room temperature and 2 days autoclave at 150 °C after 7 days at room temperature.
Figure 6 Comparison of flexural strengths as a function of time of composites using 2 different solution/slag ratios.

Chapter 22

Figure 1 (a) Diagram of the wetting angle measurement θ and (b) an example of obtained image.
Figure 2 (A) FTIR and (B) Raman spectra of (a) LNaK1.6 and (b) LNaK1.6Na0.7 solutions
Figure 3 Raman spectra of the solutions with the alkali cation molar percentages (A) varying between 3 and 5 % for _LNaK^1.6 and _CNaK^1.6, (B) 8 % for _CK^1.7_Na^0.7 and _CK^1.7_Li^0.7, (C) 12 % for _CNaK^1.6_Na^0.7, _CNaK^1.6_K^0.7, _CNa^1.7_K^0.7 and _CNa^1.7_Li^0.7 and (D) 14 % for _LK^1.7_Na^0.7, _LNa^1.7_K^0.7, _LNaK^1.6_Na^0.7 and _LNaK^1.6_K^0.7 solutions.
Figure 4 The wetting angle on polyethylene as a function of alkali cation concentration [M] (M = Na, K, Li) for solutions based on (♦) K^1.7 (•) K^0.7, (□) Na¹^.⁷ and (A) NaK^1.6 starting silicate solutions.
Figure 5 The evolution of shift values determined by FTIR spectroscopy versus the wetting angle on polyethylene for reactive mixtures based on (♦) K^1.7, (•) K^0.7 and (□) Na^1.7 starting silicate solutions.

Chapter 23

Figure 1 SEM images of TiO₂ nanopowder showing distinct particles in the range of ∼60–100 nm.
Figure 2 SEM images of ZnO nanopowder showing distinct particles in the range of ∼50–100 nm.
Figure 3 Particle size distribution for TiO₂ (solid) and ZnO (dotted) nanopowders in NaOH
Figure 4 Rate of heat evolution from MK-NaOH systems with (a) 1%TiO₂, 1%ZnO and 3%ZnO and (b) a combination of the TiO₂ and ZnO nanopowders
Figure 5 Amount of unreacted metakaolin, as measured by HCl dissolution. Error bars represents one standard deviation from the mean.
Figure 6 Compressive strength of 1" cubes with error bars representing one standard deviation from mean.

Chapter 24

Figure 1 Microphotographs of Mondo tailing, transmitted light. Figure on the left is the sample dried at 105 °C and the right one of the sample heated to 700 °C. Decarbonization of magnesite to periclase is associated to the oxidation of the magnesite bounded Fe2⁺ to a Fe3⁺ compound, thus giving the yellow tint for the synthetized periclase
Figure 2 TGA/DT analysis on LGMgO.
Figure 3 Structural equation model with path coefficients, indicator loadings and R² values.

Introduction

This Ceramic Engineering and Science Proceedings (CESP) issue consists of 24 papers that were submitted and approved from select symposia held during the 41st International Conference on Advanced Ceramics and Composites (ICACC), held January 22-27, 2017 in Daytona Beach, Florida. ICACC is the most prominent international meeting in the area of advanced structural, functional, and nanoscopic ceramics, composites, and other emerging ceramic materials and technologies. This prestigious conference has been organized by the Engineering Ceramics Division (ECD) of The American Ceramic Society (ACerS) since 1977.

The 41st ICACC hosted more than 1,000 attendees from 41 countries that gave over 850 presentations. The topics ranged from ceramic nanomaterials to structural reliability of ceramic components, which demonstrated the linkage between materials science developments at the atomic level and macro level structural applications. Papers addressed material, model, and component development and investigated the interrelations between the processing, properties, and microstruc-ture of ceramic materials.

The 2017 conference was organized into the following 15 symposia and 3 Focused Sessions and two Special Sessions:

Symposium 1	Mechanical Behavior and Performance of Ceramics and Composites
Symposium 2	Advanced Ceramic Coatings for Structural, Environmental, and Functional Applications
Symposium 3	14th International Symposium on Solid Oxide Fuel Cells (SOFC): Materials, Science, and Technology
Symposium 4	Armor Ceramics: Challenges and New Developments
Symposium 5	Next Generation Bioceramics and Biocomposites
Symposium 6	Advanced Materials and Technologies for Direct Thermal Energy Conversion and Rechargeable Energy Storage
Symposium 7	11th International Symposium on Functional Nanosmaterials and Thin Films for Sustainable Energy Harvesting, Environmental and Health Applications
Symposium 8	11th International Symposium on Advanced Processing & Manufacturing Technologies for Structural & Multifunctional Materials and Systems
Symposium 9	Porous Ceramics: Novel Developments and Applications
Symposium 10	Virtual Materials (Computational) Design and Ceramic Genome
Symposium 11	Advanced Materials and Innovative Processing ideas for the Production Root Technology
Symposium 12	Materials for Extreme Environments: Ultrahigh Temperature Ceramics (UHTCs) and Nano-laminated Ternary Carbides and Nitrides (MAX Phases)
Symposium 13	Advanced Materials for Sustainable Nuclear Fission and Fusion Energy
Symposium 14	Crystalline Materials for Electrical, Optical and Medical Applications
Symposium 15	Additive Manufacturing and 3D Printing Technologies
Focused Session 1	Geopolymers, Chemically Bonded Ceramics, Eco-friendly and Sustainable Materials
Focused Session 2	Advanced Ceramic Materials and Processing for Photonics and Energy
Focused Session 3	Carbon Nanostructures and 2D Materials and Composites
Special Symposium	3rd Pacific Rim Engineering Ceramics Summit
Special Symposium	6th Global Young Investigators Forum (GYIF)

The proceedings papers from this meeting are published in the below two issues of the 2017 Ceramic Engineering and Science Proceedings (CESP):

CESP Volume 38, Issue 2 (includes 23 papers from Symposia 1, 2, 4, 5, and GYIF)
CESP Volume 38, Issue 3 (includes 24 papers from Symposia 3, 8, 11, 12, 13, 14, 15 and FS1)

The organization of the Daytona Beach meeting and the publication of these proceedings were possible thanks to the professional staff of ACerS and the tireless dedication of many ECD members. We would especially like to express our sincere thanks to the symposia organizers, session chairs, presenters and conference attendees, for their efforts and enthusiastic participation in the vibrant and cutting-edge conference.

ACerS and the ECD invite you to attend the 42nd International Conference on Advanced Ceramics and Composites (http://www.ceramics.org/icacc2018) January 21-26, 2018 in Daytona Beach, Florida.

To purchase additional CESP issues as well as other ceramic publications, visit the ACerS-Wiley Publications home page at www.wiley.com/go/ceramics.

Surojit Gupta, University of North Dakota, USA

Jingyang Wang, Institute of Metal Research, Chinese Academy of Sciences, China

Volume Editors

August 2017 ICACC

MITIGATION OF COMPRESSOR STALL/SURGE IN A HYBRID SOLID OXIDE FUEL CELL-GAS TURBINE SYSTEM

M. Azizi^a and J. Brouwer^b

National Fuel Cell Research Center, University of California, Irvine, CA 92697, USA

ABSTRACT

One of the main purposes of an SOFC-GT hybrid system is for distributed power generation applications. This study investigates the possible use of an SOFC-GT hybrid system to power multi-MW dynamic loads. Based upon the integration of commercially available gas turbine technology, control strategies for the SOFC-GT hybrid system are investigated for different stationary power applications. Risk analysis of compressor stall/surge in the hybrid SOFC-GT power system as it is dynamically dispatched to meet demand is assessed in transient pre-load and post-load modes. Optimal control algorithm is proposed and applied to mitigate stall/surge in compressor as a response to sudden power demand change. This study aims to study compressor stall/surge mitigation assuming a connecting pipe that reduces the back pressure on the compressor in order to maintain the compressor mass flow rate at a specific setpoint.

INTRODUCTION

A better understanding of turbulent unsteady flows in compressor and gas turbine systems is a necessary step toward a breakthrough in compressor applications for hybrid fuel cell-gas turbine (FC-GT) systems transient operation. Hybrid fuel cell-gas turbines are among the many low emission power generation systems. In the previous studies at National Fuel Cell Research Center (NFCRC) at University of California, Irvine, compressor stall/surge analysis for a 4 MW locomotive hybrid solid oxide fuel cell-gas turbine (SOFC-GT) engine has been performed based on the 1.7 MW multi-stage air compressor similar to available commercial compressors¹. Controls methods have been previously developed for these types of systems in order to avoid stall/surge in the compressor². Computational fluid dynamics (CFD) tools can provide a better understanding of flow distribution and instabilities near the stall/surge line. In this study a mechanism is presented in order to mitigate stall/surge in the compressor assuming a connecting pipe between the compressor inlet and outlet that maintains constant air mass flow rate at the design condition of the compressor. This mechanism will avoid secondary stall/surge occurance in the compressor while the hybrid system is exposed to a sudden increase in power demand change from 3 MW to 3.5 MW.

TURBOMACHINERY MODELING

Shear stress transport (SST k-co) fluid model is used for faster convergence in the turbomachinery problem. The pressure dynamics of the compressor outlet has been solved in the MATLAB/Simulink platform that was previously developed at NFCRC. Computational fluid dynamics analysis of the compressor is accomplieshed using ANSYS CFX software³. Power demand variation in the hybrid SOFC-GT system causes pressure change at the compressor outlet. The pressure variation is set as a boundary condition for the turbomachinery analysis. The results show that by using a pipe guiding the exit air flow rate to the compressor inlet, the compressor mass flow rate could be maintained at the design condition of 7 kg/s. 1.7 MW compressor is an appropriate choice among the industrial compressors to be used in a 4 MW hybrid locomotive SOFC-GT system with topping cycle design due to the enhanced ability to maintain air flow rate through the compressor during the sudden transient step-load change.

RESULTS AND DISCUSSION

Figure 1 shows the pressure variation contour on the compressor front and rear impellers post stall/surge. The pressure on the compressor outlet is reduced while the compressor mass flow converges to the design condition at a constant value.

**Figure 1:** Pressure reduction and stall/surge mitigation of 1.7 MW multi-stage compressor based on controlled stall/surge assuming a connecting pipe between the compressor outlet and inlet that keeps the compressor mass flow rate at a constant rate.

Figure 2. shows the air mass flow rate increase post stall/surge on the rear impeller blades due to the controlled air flow rate to meet the mass flow rate at set point.

**Figure 2:** Air mass flow rae incease at the front impeller inlet due to the reduced back pressure on the compressor.

Figure 3. shows that it takes 10 rotor revolutions post stall/surge so that the air mass flow rate can be reached to the steady normal operating condition of the hybrid SOFC-GT system. Control algorithms are topics of future research in order to reduce the delay time between the stall/surge and the normal operating condition.

**Figure 3:** Compressor air mass flow rate increase post stall/surge to the normal design value of 7 kg/s.

CONCLUSION

In this study, analysis of post stall/surge of a 1.7 MW multi-stage compressor is investigated assuming a connecting pipe between the inlet and outlet of the compressor maintaining the compressor air mass flow rate at the 7 kg/s design condition. The reduced back pressure significantly reduces the risk of flow reversal in the 4 MW hybrid SOFC-GT system. As a result, a second stall/surge is less likely to occur after a sudden increase in the power demand is applied to the hybrid system. The response time of the air mass flow rate variation could help in future design of control systems for faster mitigation of compressor stall/surge.

ACKNOWLEDGEMENTS

The authors would like to thank Federal Railroad Administration (FRA) for its support during this research.

REFERENCES

Azizi, Mohammad Ali, and Jacob Brouwer. “Transient Analysis of 220 kW Solid Oxide Fuel Cell-Gas Turbine Hybrid System Using Computational Fluid Dynamics Results.” ECS Transactions 71.1 (2016): 289-301.
McLarty, Dustin Fogle. Thermodynamic Modeling and Dispatch of Distributed Energy Technologies including Fuel Cell-Gas Turbine Hybrids. 2013.
ANSYS® Academic Research, Release 16.0