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Numerical study of hydrogen-air combustion characteristics in a novel micro-thermophotovoltaic power generator

Alipoor, A ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1016/j.apenergy.2017.05.027
  3. Publisher: Elsevier Ltd , 2017
  4. Abstract:
  5. In the present work, a micro combustor for thermophotovoltaic (TPV) devices is proposed which is included a U-shaped microtube in a box with a secondary fluid in space between U-shaped microtube and box walls. By utilizing the three-dimensional CFD model, combustion characteristics of the premixed lean hydrogen-air mixture in the present micro combustor are studied numerically with detailed chemistry and transport taking into account heat transfer through the wall. The results show that the establishment of secondary flows and better preheating in the curved tubes is caused the flammability limits to be at least four times in comparison with straight tubes. Combustion characteristics are studied for different parameters, namely inlet velocity, wall thermal conductivity, heat loss conditions, tube curvature and number of U-shaped tubes. By increasing inlet velocity up to 16 m/s, flame front moves toward downstream, the maximum temperature is increased and rate of reactions is intensified. The highest efficiency for thermophotovoltaic devices is calculated at 4 m/s inlet velocity. A wall thermal conductivity of 3 W/m K creates a better condition for flame stability. It is shown that the secondary fluid with higher thermal diffusivity could improve combustion characteristics. Energy conversion efficiency (ηQ), emitter efficiency (ηRad) and total energy conversion efficiency of the TPV (ηtotal) is utilized to investigate the simulated cases for the present geometry. This type of micro combustor is well fitted for thermophotovoltaic applications. © 2017 Elsevier Ltd
  6. Keywords:
  7. Combustion in small scale ; Micro thermophotovoltaic (TPV) devices ; Modular micro combustor ; Numerical simulation ; U-shaped microtube ; Combustion ; Computer simulation ; Conversion efficiency ; Energy conversion ; Heat transfer ; Inlet flow ; Thermal conductivity ; Micro combustor ; Micro-thermophotovoltaic ; Micro-thermophotovoltaic power generators ; Microtube ; Small scale ; Thermophotovoltaic applications ; Thermophotovoltaic devices ; Three-dimensional CFD model ; Combustors ; Computational fluid dynamics ; Efficiency measurement ; Energy efficiency ; Equipment ; Equipment component ; Numerical method ; Photovoltaic system ; Simulation ; Temperature effect ; Thermal conductivity ; Three-dimensional modeling ; Pepper golden mosaic virus - [Mexico]
  8. Source: Applied Energy ; Volume 199 , 2017 , Pages 382-399 ; 03062619 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0306261917305305