Effects of heat recirculation on combustion characteristics of n-heptane in micro combustors

Li, Junwei; Huang, Jinghuai; Chen, Xinjian; Zhao, Dan; Shi, Baolu; Wei, Zhijun; Wang, Ningfei

doi:10.1016/j.applthermaleng.2016.08.085

Cited by 63 publications

(6 citation statements)

References 35 publications

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“…It has great potential to be implemented in combustioninvolved engines. [103][104][105][106][107][108][109][110][111][112][113][114] The acoustic damping performance of such coupled Helmholtz resonators is also related to the structures. [115][116][117][118][119] The conventional theoretical model 120,121 may not be applicable like the experimental 122,123 and numerical approaches 124,125 as discussed in the present work.…”

Section: Model Validationmentioning

confidence: 99%

Case studies on aeroacoustics damping performances of Coupled Helmholtz Resonators over low frequency ranges

Zhang

Win

2022

Journal of Low Frequency Noise, Vibration and Active Control

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Helmholtz resonators are widely applied in industries to reduce the transmission of unwanted noise and passively attenuate tonal noise in pipes/ducts. For example, internal combustion engines take advantage of Helmholtz resonators by combining air box, subwoofers and perforated pipes/plates to reduce engine noise emission nowadays. However, the main drawback of the conventional Helmholtz resonators includes a very narrow bandwidth. To broaden the effective noise damping frequency range of Helmholtz resonators, a number of different improved designs are reported and tested recently in the literature such as applying an array of separated resonators or implementing mechanical-coupled Helmholtz resonators. In this work, we conduct a brief review on the aeroacoustics damping performance of coupled Helmholtz resonators over low frequency range. The noise damping performances could be characterized and quantified in terms of transmission loss and sound absorption coefficient. Both definitions are discussed. Comparison is then made between the separately working resonators and the mechanical-coupled ones. This is achieved by replacing the sharable flexible sidewall with a rigid sidewall. The effect of the mean grazing flow is also discussed and examined on the noise damping performances. An experimental case study of the present authors is included. Additionally, to improve the noise damping performance further, an overview of the resonators neck with different noise damping materials inserted is conducted. Finally, 3D numerical approaches in simulating the aeroacoustics damping performances of coupled Helmholtz resonators are reviewed. This case study and brief overview provides a guidance on improving the design of coupled Helmholtz resonators and an array of Helmholtz resonators.

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Section: Model Validationmentioning

confidence: 99%

Case studies on aeroacoustics damping performances of Coupled Helmholtz Resonators over low frequency ranges

Zhang

Win

2022

Journal of Low Frequency Noise, Vibration and Active Control

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“…Swiss-roll combustor and combustor with a vacuum regenerator were designed to reduce large heat loss through the wall due to high surface to volume ratio and to stabilize combustion [6,7]. The effect of the calorific value of fuel on the flammability limit was investigated and the flammability limit was improved by adding H2 with the high calorific value to the hydrocarbon/air mixture [8,9].…”

Section: Introductionmentioning

confidence: 99%

Structure Optimization of Guide Vane on Combustion Performance of Premixed H2/Air in Micro Cavity-Combustor

Kim

Pak³

et al. 2022

SSRN Journal

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“…Alipoor and Saidi 15 proposed a U‐shaped micro‐combustor, and they found that the establishment of secondary flows could have better preheating capacity. Li et al 16 constructed a micro‐combustor with a vacuum regenerator and found that the heat loss is reduced by 25%, and the combustion stability is improved compared with the single‐layer regenerator. The increase in the residence time of the fuel in the combustor means that the fuel has more opportunity to participate in the combustion reaction.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of combustion and radiation performances in a counterflow double‐channel combustor with pin fins for micro‐thermophotovoltaic system

Gao

Yan

Zhang

et al. 2021

Intl J of Energy Research

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Summary As one vital role component of micro‐thermophotovoltaic (MTPV) system, the combustion characteristics of the micro‐combustor directly affect the wall temperature distribution and the MTPV system efficiency. Combined with the advantages of counterflow and pin rib arrangement, a counterflow double‐channel micro‐combustor with pin fins (combustor C) was built to enhance the heat transfer and improve the wall temperature. The combustion performances and radiation performances of single‐channel micro‐combustor (combustor A), counterflow double‐channel micro‐combustor (combustor B), and combustor C were investigated and compared under different mass flow rates (4~12 × 10−5 kg/s) and equivalence ratios (0.6~1.4). Results show that the pin fin is of positive significance for the fixation of flame root to improve the combustion stability, combustion efficiency, and radiation energy when the total mass flow rate is high, especially. When the mass flow rate is low, the combustion efficiency of combustor C is the lowest due to the limitation of combustion space. However, with the increase of the mass flow rate, the combustion characteristics of combustor C are the best due to the flame front area is larger among the three combustors and the flame root position is closer to the inlet area. The radiation energy, radiation efficiency, and mean temperature of the upper wall of the combustor C are significantly higher than other combustors under the same conditions. When the total mass flow rate is 12 × 10−5 kg/s, the radiation energy of combustor C is 0.51 times and 0.36 times that of combustor A and B, respectively. When the equivalence ratio is 1.0, the mean upper wall temperature of combustor C is 175.87 and 128.904 K higher than of combustor A and B, respectively. The counterflow double‐channels combustors have better wall temperature uniformity than single‐channel combustor under a wide range of working conditions.

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Effects of heat recirculation on combustion characteristics of n-heptane in micro combustors

Cited by 63 publications

References 35 publications

Case studies on aeroacoustics damping performances of Coupled Helmholtz Resonators over low frequency ranges

Case studies on aeroacoustics damping performances of Coupled Helmholtz Resonators over low frequency ranges

Structure Optimization of Guide Vane on Combustion Performance of Premixed H2/Air in Micro Cavity-Combustor

Enhancement of combustion and radiation performances in a counterflow double‐channel combustor with pin fins for micro‐thermophotovoltaic system

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