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Effect of heat transfer space non-uniformity of combustion chamber components on in-cylinder heat transfer

Jizu LV, Minli BAI, Long ZHOU, Jian ZHOU,

《能源前沿（英文）》 2010年第4卷第3期页码 392-401 doi: 10.1007/s11708-009-0066-1

摘要： Combustion chamber components (cylinder head-cylinder liner-piston assembly-oil film) were treated as a coupled body. Based on the three-dimensional numerical simulation of the heat transfer of the coupled body, a coupled three-dimensional calculation model for the in-cylinder working process and the combustion chamber components was built with domain decomposition and boundary coupling method, which adopts the coupled three-dimensional simulation of in-cylinder working process and the combustion chamber components. The model was applied in the investigation of the influence of space non-uniformity in heat transfer among combustion chamber components on in-cylinder heat transfer. The results show that the effect of wall temperature space non-uniform distribution of combustion chamber components on heat transfer happens mainly at the end of the compression stroke and expansion stroke. Therefore, it can be concluded that wall temperature space non-uniform distribution of combustion chamber components would influence heat transfer during the intake and exhaust stroke obviously.

关键词： heat transfer space non-uniformity soot emission in-cylinder diesel

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DEVELOPMENT OF AN AUTOMATIC WEIGHING PLATFORM FOR MONITORING BODYWEIGHT OF BROILER CHICKENS IN COMMERCIAL PRODUCTION

《农业科学与工程前沿（英文）》 2023年第10卷第3期页码 363-373 doi: 10.15302/J-FASE-2023510

摘要：

● An automatic weighing system for monitoring bodyweight of broilers was developed.

关键词： automatic weighing weight monitoring floor housing uniformity precision poultry farming

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Knife-edge technique for laser cooling

WANG Zhanshan, MA Shanshan, MA Yan, ZHAO Min, LIU Hengbiao

《机械工程前沿（英文）》 2007年第2卷第4期页码 468-473 doi: 10.1007/s11465-007-0081-z

摘要： The transfer characteristics of an atomic beam and the effect of laser were investigated in this paper. In the application of knife-edge technique, the temperature of atoms through laser cooling was measured. Results indicate that, after atoms are emitted from an atomic oven, the longer the atoms move, the worse the distribution of the atomic beam shows, regardless the laser cooling is taken or not. Laser cooling can reduce the transverse velocity of the atomic beam to several orders of magnitude and also increase the uniformity of an atomic beam. Knife-edge technique can measure the temperature of an atomic beam through laser cooling. The measurement accuracy depends on the pixel size of the charge coupled device (CCD), which is used for the fluorescent imaging of the atomic beam. The results are very important for the future experiments of laser cooling.

关键词： knife-edge technique uniformity coupled transfer fluorescent

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Modeling and optimization of an enhanced battery thermal management system in electric vehicles

Mao LI, Yuanzhi LIU, Xiaobang WANG, Jie ZHANG

《机械工程前沿（英文）》 2019年第14卷第1期页码 65-75 doi: 10.1007/s11465-018-0520-z

摘要： This paper models and optimizes an air-based battery thermal management system (BTMS) in a battery module with 36 battery lithium-ion cells. A design of experiments is performed to study the effects of three key parameters (i.e., mass flow rate of cooling air, heat flux from the battery cell to the cooling air, and passage spacing size) on the battery thermal performance. Three metrics are used to evaluate the BTMS thermal performance, including (i) the maximum temperature in the battery module, (ii) the temperature uniformity in the battery module, and (iii) the pressure drop. It is found that (i) increasing the total mass flow rate may result in a more non-uniform distribution of the passage mass flow rate among passages, and (ii) a large passage spacing size may worsen the temperature uniformity on the battery walls. Optimization is also performed to optimize the passage spacing size. Results show that the maximum temperature difference of the cooling air in passages is reduced from 23.9 to 2.1 K by 91.2%, and the maximum temperature difference among the battery cells is reduced from 25.7 to 6.4 K by 75.1%.

关键词： thermal management electric vehicle lithium-ion battery temperature uniformity design optimization

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Design and analysis of electrothermal metasurfaces

Xiu LIU, Zhuo LI, Zexiao WANG, Hyeong Seok YUN, Sheng SHEN

《能源前沿（英文）》 2023年第17卷第1期页码 134-140 doi: 10.1007/s11708-022-0841-9

摘要： Electrothermal metasurfaces have garnered considerable attention owing to their ability to dynamically control thermal infrared radiation. Although previous studies were mainly focused on metasurfaces with infinite unit cells, in practice, the finite-size effect can be a critical design factor for developing thermal metasurfaces with fast response and broad temperature uniformity. Here, we study the thermal metasurfaces consisting of gold nanorods with a finite array size, which can achieve a resonance close to that of the infinite case with only several periods. More importantly, such a small footprint due to the finite array size yields response time down to a nanosecond level. Furthermore, the number of the unit cells in the direction perpendicular to the axis of nanorods is found to be insensitive to the resonance and response time; thus, providing a tunable aspect ratio that can boost the temperature uniformity in the sub-Kelvin level.

关键词： modulated thermal infrared radiation metasurface nanosecond response time sub-Kelvin temperature uniformity finite size aspect ratio