Enhancing Thermal Performance Investigations of a Methane-Fueled Planar Micro-Combustor with a Counter-Flow Flame Configuration
To enhance the performance of combustors in micro thermophotovoltaic systems, this study employs numerical simulations to investigate a planar microscale combustor featuring a counter-flow flame configuration. The analysis begins with an evaluation of the effects of (1) equivalence ratio <i>Φ&...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Energies |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1073/18/1/195 |
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| Summary: | To enhance the performance of combustors in micro thermophotovoltaic systems, this study employs numerical simulations to investigate a planar microscale combustor featuring a counter-flow flame configuration. The analysis begins with an evaluation of the effects of (1) equivalence ratio <i>Φ</i> and (2) inlet flow rate <i>V<sub>i</sub></i> on key thermal and combustion parameters, including the average temperature of the combustor main wall (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mover accent="true"><mrow><mi>T</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>w</mi></mrow></msub></mrow></semantics></math></inline-formula>), wall temperature non-uniformity (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mover accent="true"><mrow><mi>R</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>T</mi><mi>w</mi></mrow></msub></mrow></semantics></math></inline-formula>) and radiation efficiency (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>η</mi></mrow><mrow><mi>r</mi></mrow></msub></mrow></semantics></math></inline-formula>). The findings indicate that increasing <i>Φ</i> causes these parameters to initially increase and subsequently decrease. Similarly, increasing the inlet flow rate leads to a monotonic decline in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>η</mi></mrow><mrow><mi>r</mi></mrow></msub></mrow></semantics></math></inline-formula>, while the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mover accent="true"><mrow><mi>T</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>w</mi></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mover accent="true"><mrow><mi>R</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>T</mi><mi>w</mi></mrow></msub></mrow></semantics></math></inline-formula> exhibit a rise-then-fall trend. A comparative study between the proposed combustor and a conventional planar combustor reveals that, under identical inlet flow rate and equivalence ratio conditions, the use of the counterflow flame configuration can increase the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mover accent="true"><mrow><mi>T</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>w</mi></mrow></msub></mrow></semantics></math></inline-formula> while reducing the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mover accent="true"><mrow><mi>R</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>T</mi><mi>w</mi></mrow></msub></mrow></semantics></math></inline-formula>. The Nusselt number analysis shows that the counter-flow flame configuration micro-combustor achieves a larger area with positive Nusselt numbers and higher average Nusselt numbers, which highlights improved heat transfer from the fluid to the solid. Furthermore, the comparison of blow-off limits shows that the combustor with counter-flow flame configuration exhibits superior flame stability and a broader flammability range. Overall, this study provides a preliminary investigation into the use of counter-flow flame configurations in microscale combustors. |
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| ISSN: | 1996-1073 |