Abstract
Micro-combustor can provide the required thermal energy of micro-thermal photovoltaic (MTPV) systems. The performance of MTPV is greatly affected by the effectiveness of a micro-combustor. In this study, a numerical simulation was conducted to explore the benefits of annular rectangular rib for enhancing the thermal performance of a nonpremixed micro-combustor. Based on the investigations under various rib heights, rib positions, and inlet mass flow rates, it is found that the addition of annular rectangular ribs in the micro-combustor creates a turbulent zone in the combustion chamber, thereby enhancing the heat transfer efficiency between the inner wall of the combustion chamber and the burned gas. The micro-combustor with annular rectangular rib shows a higher and more uniform wall temperature. When the H2 mass flow is 7.438 × 10−8 kg/s and the air mass flow is 2.576 × 10−6 kg/s, the optimum dimensionless rib position is at l = 6/9 and r = 0.4. At this condition, the micro-combustor has the most effective and uniform heat transfer performance and shows significant decreases in entropy generation and exergy destruction. However, the optimum l and r significantly depend on the inlet mass flow of H2/air mixture.
Highlights
micro-thermal photovoltaic (MTPV) system has the problem of low total energy conversion efficiency [24,25,26,27]
It can be observed that the change in rib positions and rib heights of the annular rectangular ribs in the micro-combustor is proportional to the temperature distribution of flow field
It can be seen from the figure that when the l of the microcombustor is a fixed constant, the temperature at outer wall increases as the r increases. is can be explained by the fact that, by the raise of the dimensionless rib heights, the turbulence zone becomes wider, and the turbulence area at the rear of the annular rectangular rib expands in proportion to the dimensionless rib heights, effectively improving the heat transmission capability of the micro-combustor
Summary
E H2 and air mass flow rates are both considered as the inlet boundary conditions, while the outlet pressure was used as the outlet boundary condition. Both convective and radiative heat transfer of the environment are considered in the outer wall of the combustion chamber. In both boundaries the gauge pressure is set to 0 MPa. A unified 2D grid is built to calculate the heat transfer and the combustion in the micro-combustor. Note: Ak is the preexponential factor of reaction rate, βk is the temperature exponent, and Ek is the activation energy of the reaction
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
