Browsing by Author "Wei, S. -S."

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Investigation of Dual-Vortical-Flow Hybrid Rocket Engine without Flame Holding Mechanism
(2018-01-01)
Lai, A.
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Chou, T. -H.
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Wei, S. -S.
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Lin, J. -W.
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Wu, J. -S.
A 250 kgf thrust hybrid rocket engine was designed, tested, and verified in this work. Due to the injection and flow pattern of this engine, this engine was named dual-vortical-flow engine. This propulsion system uses N2O as oxidizer and HDPE as fuel. This engine was numerically investigated using a CFD tool that can handle reacting flow with finite-rate chemistry and coupled with the real-fluid model. The engine was further verified via a hot-fire test for 12 s. The ground I-sp of the engine was 232 s and 221 s for numerical and hot-fire tests, respectively. An oscillation frequency with an order of 100 Hz was observed in both numerical and hot-fire tests with less than 5% of pressure oscillation. Swirling pattern on the fuel surface was also observed in both numerical and hot-fire test, which proves that this swirling dual-vortical-flow engine works exactly as designed. The averaged regression rate of the fuel surface was found to be 0.6 similar to 0.8 mm/s at the surface of disk walls and 1.5 similar to 1.7 mm/s at the surface of central core of the fuel grain.
Numerical modeling of interconnect flow channel design and thermal stress analysis of a planar anode-supported solid oxide fuel cell stack
(2014-05-01)
Wei, S. -S.
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Wang, T. -H.
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Wu, J. -S.
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機械工程學系
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Department of Mechanical Engineering
In this paper, we propose a new design of flow channel and stack arrangement based on the numerical study considering the effect of the flow channel design on the stack performance and analyze the thermal stress of a planar anode-supported solid oxide fuel cell stack. We also attempt to simplify the cell stack design without affecting its performance and propose an easier sealing method of cell stacks through the study of the thermal stress distribution. The results indicate that the new design, created by changing the cathode flow channel to a porous current collector, with a 6.3% increase in power density. an 8.6% increase in electrical efficiency. Both more uniform flow and current density distribution can be obtained as compared with a conventional counter-flow design. In addition, we propose a new design direction of cell stack, which could be simpler and easier to fabricate, in which material can easily undertake the resulting stress based on the thermal stress analysis. (C) 2014 Elsevier Ltd. All rights reserved.