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

Khaleghi, Mostafa; Hosseini, Seyed Ehsan; Wahid, Mazlan Abdul

doi:10.1016/j.icheatmasstransfer.2015.06.005

Cited by 8 publications

(4 citation statements)

References 25 publications

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“…To recover the heat from small-scale combustor, Khaleghi et al 2 presented a non-premixed mesoscale vortex combustion with thermal recuperator in lean, stoichiometry and rich conditions based on the concept of asymmetric whirl combustion which was developed by Gabler et al 78 The effects of equivalence ratio on the wall temperature and emitter efficiency was considered by the authors (Figure 5(b)). The authors reported that the position of the flame has great impact on the emitter efficiency.…”

Section: Combustion-based Micro-power Generationmentioning

confidence: 99%

“…Nevertheless, improvements in thermal and chemical management and proper diagnostic and control of the system would illustrate significant progress in the development of miniaturized combustion. 2 Due to significant interest in producing small-scale mechanical devices (micro-pumps/motors/airplanes/rovers), new opportunities have been opened for combustion research society because of the requests for highefficiently power supply systems with long duration, low weight, and small size.…”

Section: Introductionmentioning

confidence: 99%

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Micro-power generation using micro-turbine (moving) and thermophotovoltaic (non-moving) systems

Hosseini

2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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Combustion-based micro-power generation is a serious candidate for substitution of traditional batteries. As the volume of combustion system decreases to small-scale combustors, ignition and combustion stability are becoming considerable challenges due to short residence time and large heat loss. To overcome these shortages, several experimental investigations have been implemented to generate micro-power using both moving (micro-turbines) and non-moving (thermophotovoltaic) systems. Although the goal of both systems is to generate micro-power via combustion phenomenon, the approaches to the goal is different. Nevertheless, combustion instability and various shortages in burner and combustor have been noticed by several researchers regardless of the micro-power generation method. In this paper, a review about recent development in application of small-scale combustion in micro-power generation and micro-thruster systems using micro-turbine and thermophotovoltaic systems is presented. The special focus of this paper is on flame regimes, fuel/oxidizer mixing, flame stability conditions, heat recirculation, non-equilibrium transport, flame-wall thermal and kinetic couplings, and improvement of energy conversion efficiency.

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Section: Combustion-based Micro-power Generationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Micro-power generation using micro-turbine (moving) and thermophotovoltaic (non-moving) systems

Hosseini

2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…The vortices inside a micro combustor [4][5][6][7][8][9][10] is divided into two patterns near the combustor center and the chamber wall. In many combustors, the recirculations near the chamber wall contribute to the increase the wall heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Effects of blade angle on combustion characteristics in a micro combustor with a swirler of micro fan type

Kim

Park

2019

JMST Adv.

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In a micro combustor, various vortices can enhance the wall heat transfer rate and get the best combustion. For an efficient combustion, the swirler of micro fan type is introduced for a micro combustor. In general, the swirling flows can change significantly the wall heat fluxes and this feature is sensitively varied by the fan configuration. So, to examine the geometric effect of fan swirler on the combustion characteristics, reacting flows depending on six blade angles are numerically investigated. The highest efficiency and heat loss related to vortical flows are observed for the specific blade angles. Keywords Micro combustor • Blade angle • Fan swirler • Heat loss • Combustion efficiency • Swirl flow List of symbols A i Surface area of combustion chamber, m 2 D Combustor diameter, m D f Fuel hole diameter, m D o Outer wall diameter, m q i Wall heat flux, W/m 2 m inlet CH 4 CH4 mass flow rate of inlet, kg/s LHV Lower heating value of methane, kJ/kg T Temperature U Streamwise velocity, m/s U c Streamwise velocity at center axis, m/s Z Mixture fraction Z st Stoichiometric mixture fraction ν t Kinematic viscosity ϕ G Global equivalence ratio θ Blade angle, degree

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“…The functionality of portable micro-electro-mechanic-systems (MEMS) will be significantly improved by availability of high-performance small-scale power generators. Nevertheless, improvements in thermal and chemical management and proper diagnostic and control of the system would illustrate significant progress in the development of miniaturized combustion [2]. The increasing requests to reduce system weight, mitigate system cost and enhance unit operational lifetimes have encouraged MEMS investigators to study about various concepts behind of this new field [3].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation into the Effects of Thermal Recuperation on the Combustion Characteristics of a Non-Premixed Meso-Scale Vortex Combustor

et al. 2018

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In small-scale combustors, the ratio of area to the combustor volume increases and hence heat loss from the combustor’s wall is significantly enhanced and flame quenching occurs. To solve this problem, non-premixed vortex flow is employed to stabilize flames in a meso-scale combustion chamber to generate small-scale power or thrust for propulsion systems. In this experimental investigation, the effects of thermal recuperation on the characteristics of asymmetric non-premixed vortex combustion are studied. The exhaust gases temperature, emissions and the combustor wall temperature are measured to evaluate thermal and emitter efficiencies. The results illustrate that in both combustors (with/without thermal recuperator), by increasing the combustion air mass flowrate, the wall temperature increases while the wall temperature of combustor with thermal recuperator is higher. The emitter efficiency calculated based on the combustor wall temperature is significantly increased by using thermal recuperator. Thermal efficiency of the combustion system increases up to 10% when thermal recuperator is employed especially in moderate Reynolds numbers (combustion air flow rate is 120 mg/s).

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

Cited by 8 publications

References 25 publications

Micro-power generation using micro-turbine (moving) and thermophotovoltaic (non-moving) systems

Micro-power generation using micro-turbine (moving) and thermophotovoltaic (non-moving) systems

Effects of blade angle on combustion characteristics in a micro combustor with a swirler of micro fan type

Experimental Investigation into the Effects of Thermal Recuperation on the Combustion Characteristics of a Non-Premixed Meso-Scale Vortex Combustor

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