Investigation on premixed H2/C3H8/air combustion in porous medium combustor for the micro thermophotovoltaic application

Peng, Qingguo; Yang, Wenming; Jiaqiang, E; Xu, Hongpeng; Li, Zhenwei; Tay, Kunlin; Zeng, Guang; Yu, Wenbin

doi:10.1016/j.apenergy.2019.114352

Cited by 73 publications

(10 citation statements)

References 63 publications

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“…MTPV system, which converts thermal energy into electricity via special materials based on microcombustion, owns lots of advantages, including high energy density, simple structure and without moving components. 3,4 Based on high energy density of hydrocarbon or hydrogen fuel, micro-and mesoscale combustion has a wide range of potential applications. [5][6][7] However, due to tiny size and large surface-to-volume, the micro-combustor faces the challenges of large heat loss and flame instability.…”

Section: Introductionmentioning

confidence: 99%

“…Micro‐thermoelectric system has low energy conversion efficiency due to the large heat loss and flame instability of micro‐combustor and needs additionally cooling system to dissipate heat. MTPV system, which converts thermal energy into electricity via special materials based on micro–combustion, owns lots of advantages, including high energy density, simple structure and without moving components 3,4 . Based on high energy density of hydrocarbon or hydrogen fuel, micro‐and mesoscale combustion has a wide range of potential applications 5‐7 .…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigations on the emitter power and energy conversion efficiency improvement of micro‐cylindrical combustor by an internal spiral fin for micro‐thermophotovoltaic systems

Zhao

Yan

et al. 2021

Int J Energy Res

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Aiming at improving the energy output and energy conversion efficiency of thermophotovoltaic systems, a micro-combustor with high and uniform outer wall temperature is desirable. Therefore, the micro-cylindrical combustor with a novel micro-spiral fin is proposed to improve the thermal performance. The effect of inlet velocities of premixed hydrogen/air, the critical design parameters of the spiral fin length (L) and the spiral fin pitch (W) on the thermal performance of the micro-cylindrical combustor are numerically investigated.Results show that micro-spiral fin is beneficial to improve the outer wall temperature value and uniformity, which can significantly increase the emitter power and energy conversion efficiency of micro-cylindrical combustor. However, the improvement of thermal performance is at the cost of higher pressure loss. Furthermore, compared with all the investigated geometrical models, the micro-cylindrical combustor with spiral fin length at the size of 14 mm and spiral fin pitch at the size of 2.355 mm obtains the best comprehensive heat transfer performance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical investigations on the emitter power and energy conversion efficiency improvement of micro‐cylindrical combustor by an internal spiral fin for micro‐thermophotovoltaic systems

Zhao

Yan

et al. 2021

Int J Energy Res

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“…Therefore, the flame anchors in the recirculation zones especially in the inner recirculation zone. Peng et al 27 demonstrated that porous medium causes to enhance heat transfer to the wall. Therefore, wall has higher temperature distribution, as the porous medium is installed in a stepped micro tube after the step.…”

Section: Introductionmentioning

confidence: 99%

Combustion characteristics of hydrogen‐air mixture in a radial micro combustor for using in thermophotovoltaic devices

2021

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Requirement of a fast rechargeable and powerful energy source for micro scale devices leads to increase attentions to various micro combustors for usage as heat source in micro thermophotovoltaic devices. Meanwhile, extracting as much thermal energy as possible from chemical energy of fuel by testing a variety of shapes of micro combustion chambers is at the heart of micro combustion subject. Present research has been purposed to find out performance and feasibility of a radial micro combustion chamber by numerical study of combustion characteristics of H 2 -air pre-mixture and calculation of emitter and total efficiency of the system. Governing equations are considered three-dimensional, incompressible, and steady state for turbulent combustion. In addition, detailed kinetics of H 2 -air combustion is chosen for the combustion mechanism. Inlet velocity, equivalence ratio, and wall material properties consisting of emissivity and thermal conductivity with external thermal convection coefficient are parameters, which have been chosen for investigations. Results indicated drastic effect of inlet velocity on the location of combustion zone. In fact, increasement of the inlet velocity causes to transfer combustion zone to the wall, which leads to increase wall temperature and consequently, emitter and total efficiency of the system. Equivalence ratio has more impact on the combustion temperature. While wall thermal conductivity and wall radiation emissivity play a decisive role in the total efficiency of the system. It was founded as the wall radiation emissivity decreases, heat recirculation increases. It causes to expand high temperature zone through the fluid and wall so that the total efficiency increases.By considering the present radial micro combustion chamber as a heat source for a micro thermophotovoltaic device, it was founded that maximum total efficiency of 3.14% is accessible for the condition in which the outer wall surface has maximum average temperature. Highlights• The inlet velocity has drastic impact on the radiation heat transfer rate.• Existence of the vortexes is suitable for intensifying the reactions.• Wall thermal conductivity has maximum effect on the emitter and total efficiency.

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“…It is found that the porous media embedding improves the temperature uniformity of the outer wall, meanwhile improves the energy conversion efficiency of the overall system. Peng et al [44] experimentally studied the heat transfer characteristics of the embedded porous medium combustor, and analyzed the influence of the porous medium material and the porosity. It was found that the pore ratio of 0.9 showed the highest average outer wall temperature and maintained excellent temperature uniformity.…”

Section: Introductionmentioning

confidence: 99%

Influence of Porous Media Aperture Arrangement on CH4/Air Combustion Characteristics in Micro Combustor

Wang

Feng

et al. 2021

Processes

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Micro-electro-mechanical systems (MEMS) occupy an important position in the national economy and military fields, and have attracted great attention from a large number of scholars. As an important part of the micro-electromechanical system, the micro-combustor has serious heat loss due to its small size, unstable combustion and low combustion efficiency. Aiming at enhancing the heat transfer of the micro-combustor, improving the combustion stability and high-efficiency combustion, this paper embedded porous media in the combustor, and the effects of different parameters on the combustion characteristics were numerically studied. The research results showed that the layout of porous media should be reasonable, and the small and large pore porous media embedded in the inner and outer layers, respectively, can bring better combustion performance. Meanwhile, A: 10–30 has a high and uniform temperature distribution, and its methane conversion rate reached 97.4%. However, the diameter ratio of the inner layer to the outer layer (d/D) of the porous medium should be maintained at 0.4–0.6, which brings a longer gas residence time, and further enables the pre-mixed gas to preheat and burn completely. At a d/D of 0.5, the combustor has the highest outer wall temperature and CH4 conversion efficiency. Besides, compared with the pore size increasing rate of Δn = 10 PPI and Δn = 10 PPI, the radial temperature distribution of the Δn = 10 PPI combustor is more uniform, meanwhile avoids the occurrence of local high temperature. Under the condition of Δn = 10 PPI, A: 20–30 layout maintains excellent thermal and combustion performance. In addition, the lean flammable limits of MC-U20, MC-10/30-0.8, and MC-20/30-0.5 were compared, at an inlet velocity of 0.5 m/s, the corresponding lean flammable limits are 0.5, 0.4, and 0.3, respectively, among them MC-20/30-0.5 has a wider flammable limit range, showing excellent combustion stability. This research has guiding significance for the combustion stability of the micro combustor.

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Investigation on premixed H2/C3H8/air combustion in porous medium combustor for the micro thermophotovoltaic application

Cited by 73 publications

References 63 publications

Numerical investigations on the emitter power and energy conversion efficiency improvement of micro‐cylindrical combustor by an internal spiral fin for micro‐thermophotovoltaic systems

Numerical investigations on the emitter power and energy conversion efficiency improvement of micro‐cylindrical combustor by an internal spiral fin for micro‐thermophotovoltaic systems

Combustion characteristics of hydrogen‐air mixture in a radial micro combustor for using in thermophotovoltaic devices

Influence of Porous Media Aperture Arrangement on CH4/Air Combustion Characteristics in Micro Combustor

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