Studies on a heat-recirculating microemitter for a micro thermophotovoltaic system

Lee, K.H.; Kwon, Oh Chae

doi:10.1016/j.combustflame.2008.01.003

Cited by 62 publications

(9 citation statements)

References 14 publications

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“…Since then, several research works have successfully demonstrated combustion in micro and meso-scale [2][3][4]. Research groups build devices with various applications of small scale combustor, such as micro burners have been integrated with thermoelectric [5,6] and thermophotovoltaic [7][8][9] for power and energy applications. Other micro combustion applications include micro propulsion [10,11], calorimetry [12], and carbon-isotopic analysis in biogeography [13,14].…”

Section: Introductionmentioning

confidence: 99%

Vortex combustion and heat transfer in meso-scale with thermal recuperation

Khaleghi

Hosseini

Wahid

2015

International Communications in Heat and Mass Transfer

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Section: Introductionmentioning

confidence: 99%

Vortex combustion and heat transfer in meso-scale with thermal recuperation

Khaleghi

Hosseini

Wahid

2015

International Communications in Heat and Mass Transfer

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“…A group at Sungkyunkwan University also conducted plenty of works on micro TPV systems [35][36][37]. As shown in Figure 1.14, the cylindrical micro-combustor has an annular shield that enables the exhaust gas to preheat the incoming fresh mixture.…”

Section: Previous Work 131 Development Of the Micro-power Devicesmentioning

confidence: 99%

“…The outer surface of the pyrolytic graphite wafer (not facing the flame) was fairly unmarked. As a comparison, experiments using stainless steel plates (SS 316) of the dimension 80 mm × 60 mm × 2 mm which were used as micro-combustor materials in previous works [27,31,35,36] were also conducted. Stainless steel has the thermal conductivity and other properties [155,156] as reported in the table 5.1.…”

Section: Experiments Setupmentioning

confidence: 99%

“…Radiation from the highemissivity (0.8 -0.9 reported in [35]) SiC foams dominates the contribution to the power output. The power output first increases as the inflow velocity increases with more input energy being introduced, until it reaches the highest values of P max = 121.1 mW, at the inflow velocity of U in = 0.49 m/s.…”

Section: Tpv Performancementioning

confidence: 99%

“…Thermophotovoltaic (TPV) system, as an alternative structurally simple direct energy conversion device, has also been extensively studied for its application in both conventional [173][174][175][176][177][178][179][180] and small scale systems [35,36,38,39,167,[181][182][183][184][185][186][187][188]. In a micro-combustion based TPV system, the combustor walls are heated to a high temperature and consequently act as an emitter to radiate photons to the surroundings.…”

Section: Introductionmentioning

confidence: 99%

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Micro/mesoscale combustion based portable power generating system

Kang¹

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Micro/mesoscale combustion-driven power generation is a promising alternative to replace traditional batteries for powering small scale electronics owing to its much higher energy densities. However, the considerable heat losses from the combustor walls due to the dramatically increased surface-tovolume ratio, as well as the short flow residence time at small scales pose a technical challenge in stabilising the flame inside the micro/mesoscale combustor. On the other hand, the significantly enhanced flame-wall thermal coupling at small scales can also lead to some unique flame characteristics.Recently, solid state power conversion of the heat released in the micro/mesoscale combustor such as thermoelectric (TE) and thermophotovoltaic (TPV) has been favoured over traditional power conversion methods such as micro-turbines. This is due to the excessive mechanical and viscous losses that rotating machinery suffers from upon miniaturisation.One of the main aims of this thesis is to perform numerical simulations to investigate the fundamental aspects of micro/mesoscale combustion, such as micro-flame behaviours of propagation and stabilisation, the conditions under which flame dynamics occur and the choices that suppress them. A set of modelling techniques that gives guidelines and practices for performing the time-accurate micro/mesoscale combustion simulations has been developed through investigation. Knowledge on standard and well-accepted numerical methods in literature are collected in a cohesive document. The less well-established modelling choices have been thoroughly evaluated and discussed.Using the developed numerical models, the effects of hydrogen and carbon monoxide addition on premixed methane/air flame dynamics is investigated. Results show that the flame instabilities which exist in pure methane/air flames could be effectively suppressed via a small amount of additives. Deep understanding of the underlying physics and chemistry has been gained. The effects of wall temperature profiles on the simulated micro-flame behaviours are also studied. The role of the combustion heat release and the gas-solid heat transfer in determining the micro-flame propagation speed is identified.Experimental works are also carried out, towards a full system demonstration for micro-power generation. The focus is placed on the "wall thermal engineering" on the improvement of the combustor performance and power output. The thermally-orthotropic pyrolytic graphite for the combustor wall material is explored. Compared to an isotropic material of stainless steel, a widened flame stability limit with pyrolytic graphite is demonstrated. Moreover, a uniform and moderate temperature distribution over the combustor surface is achieved, which is favourable for thermoelectric power conversion applications. Meanwhile, a novel, compact mesoscale thermophotovoltaic power generating system using a combination of porous media combustion and a simple band-pass filtering method is developed. The use of the porous media effectively enh...

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Effects of combustor size and filling condition on stability limits of premixed H₂‐air flames in planar microcombustors

Wang

Chen

et al. 2015

AIChE Journal

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An experimental study on stability limits of premixed hydrogen‐air flames in planar microcombustors (H = 1 mm and 1.5 mm) partially filled with porous medium is carried out, focusing on the effects of combustor sizes and filling conditions. Critical conditions for blow‐off, flashback, and breaking through the porous medium are experimentally measured. The blow‐off limits are nearly independent of combustor sizes and filling conditions, while the flashback limits are strongly influenced by the combustor size and the filling conditions. Critical values for breaking through are identified with two different methods, and it is shown that standing combustion waves are settled over a range of velocities, instead of a fixed value of filtration velocity, which is considered an important characteristic of microcombustion. Most results can be explained by the classic boundary velocity gradient theory by von Elbe and Lewis, and thus the validity of the theory to the present channel spacings is confirmed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2571–2580, 2015

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Studies on a heat-recirculating microemitter for a micro thermophotovoltaic system

Cited by 62 publications

References 14 publications

Vortex combustion and heat transfer in meso-scale with thermal recuperation

Vortex combustion and heat transfer in meso-scale with thermal recuperation

Micro/mesoscale combustion based portable power generating system

Effects of combustor size and filling condition on stability limits of premixed H₂‐air flames in planar microcombustors

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Studies on a heat-recirculating microemitter for a micro thermophotovoltaic system

Cited by 62 publications

References 14 publications

Vortex combustion and heat transfer in meso-scale with thermal recuperation

Vortex combustion and heat transfer in meso-scale with thermal recuperation

Micro/mesoscale combustion based portable power generating system

Effects of combustor size and filling condition on stability limits of premixed H2‐air flames in planar microcombustors

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Effects of combustor size and filling condition on stability limits of premixed H₂‐air flames in planar microcombustors