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Your search keyword '"Nianyong ZHOU"' showing total 6 results
Start Over Author "Nianyong ZHOU" Topic heat transfer
6 results on '"Nianyong ZHOU"'

1. Numerical simulation of the influencing factors of array jet shock cooling.

Author

Nianyong ZHOU, Youxin ZOU, Yingjie ZHAO, Qingguo BAO, Guanghua TANG, and Wenyu LV

Subjects
*JET planes, *HEAT transfer coefficient, *JET impingement, *COOLING, *JET nozzles, *DIVERSION structures (Hydraulic engineering), *HEAT transfer, *HEAT flux
Abstract

Array jet impingement cooling is a significant technology of enhanced heat dissipation which is fit for high heat flux flow with large area. It is gradually applied to the cooling of electronic devices. However, The research on the nozzle array mode and the uniformity of the cooling surface still has deficiencies. Therefore, the influence of heat flux, inlet temperature, jet height, array mode, and diversion structure on jet impingement cooling performance and temperature distribution uniformity is analyzed through numerical calculation. The results show that the heat transfer coefficient of jet impingement cooling increases linearly with the increment of heat flux and inlet temperature. With the increment of the ratio of jet height to nozzle diameter (H/d), the heat transfer coefficient increases first and then decreases, that is, there is an optimal H/d, which makes the heat transfer performance of the array jet impact cooling best. The temperature uniformity of array jet impact cooling is greatly affected by array mode. The improvement effect of nozzle array mode on temperature uniformity is ranked as sequential >staggered >shield >elliptical array. The overall temperature uniformity and heat transfer coefficient are increased by 5.88% and 7.29% compared with the elliptical array. The heat transfer performance can be further improved by adding a flow channel to the in-line array layout, in which the heat transfer coefficient is increased by 6.53% and the overall temperature uniformity is increased by 1.45%. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Heat transfer performance and influences of spray cooling under quenching

Author

Nianyong Zhou, Feng Hao, Enhai Liu, and Muhao Xu

Subjects
Quenching, Materials science, Renewable Energy, Sustainability and the Environment, Spray cooling, Physics::Instrumentation and Detectors, transient spray cooling, Physics::Fluid Dynamics, Chemical engineering, Heat transfer, surface heat transfer, TJ1-1570, cooling rate, Mechanical engineering and machinery, surface temperature drop
Abstract

In this study, a closed-loop spray cooling system using R134a as the working fluid was established. The heat transfer characteristics and influencing mechanism of transient spray cooling were studied. The transient spray cooling curve under quenching was built accurately. The results show that the vapor film suppressed time, tsup, is the main period that the spray cooling must pass through. The flow rate and the sub-cooling of R134a have little effect on the cooling rate but the critical heat flux, which are mainly affected by chamber pressure. The transient Jacob number decreases with the increases of chamber pressure. As Jacob number decreases, the growth of vapor film is inhibited, then the tsup reduces in consequence. The surface temperature drop point and critical heat flux increases with the rise of chamber pressure. The maximum critical heat flux is 70.08 W/cm2 in this experiment.

Published
2021

4. NUMERICAL STUDY ON THE NATURALLY CAPTURED AIR VOLUME OF OUTSIDE CABIN HEAT EXCHANGER FOR WIND POWER GENERATION.

Author

Nianyong ZHOU, Yixing GUO, Wenbo LIU, Hao FENG, Haoping PENG, Yun LEI, Song DENG, and Lei ZHAO

Subjects
*HEAT exchangers, *WIND power, *WIND speed, *HEAT transfer, *POROUS materials
Abstract

In this paper, the outside cabin heat exchanger based on the porous media approach was established. The effects of altitude, viscous resistance coefficient, inertial resistance coefficient, and core thickness on the naturally captured air volume of the heat exchanger were investigated by numerical simulation. Results showed that the naturally captured air volume of the heat exchanger tends to be larger on both sides and smaller in the middle, and there is a quasi-linear increase proportional to the incoming wind velocity. With the increment of altitude, viscous resistance coefficient, and inertial resistance coefficient, the average naturally captured air volume of the heat exchangers shows a downward trend. The trend would be clear with the increment of the incoming wind velocity, nevertheless, the effect of core thickness is weak. In addition, the design values of the viscous resistance coefficient and the inertial resistance coefficient should be restricted in the order of 106 and below 500, respectively. Based on the weak effect of the naturally captured air volume of the heat exchanger, the thickness of the core can be appropriately increased to ensure the heat transfer area of the heat exchanger. [ABSTRACT FROM AUTHOR]

Published
2022
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5. Influence of the Refrigerant Charge on the Heat Transfer Performance for a Closed-Loop Spray Cooling System

Author

Nianyong Zhou, Lei Yun, Yixing Guo, Deng Song, Yu Wang, Haoping Peng, Hao Feng, and Wenbo Liu

Subjects
Technology, Control and Optimization, Materials science, spray cooling, Convective heat transfer, Renewable Energy, Sustainability and the Environment, Critical heat flux, Energy Engineering and Power Technology, refrigerant charge, Mechanics, Heat transfer coefficient, Thermal conduction, Physics::Fluid Dynamics, surface temperature drop point, heat transfer performance, Refrigerant, Heat flux, Heat transfer, Electrical and Electronic Engineering, Engineering (miscellaneous), Nucleate boiling, Energy (miscellaneous)
Abstract

With the rapid increase of heat flux and demand for miniaturization of electronic equipment, the traditional heat conduction and convective heat transfer methods could not meet the needs. Therefore, the spray cooling experiment was carried out to obtain the basic heat transfer and cooling process. In this experiment, the spray cooling system was set up to investigate the influence of refrigerant charge on heat transfer performance in steady-state, dynamic heating, and dissipating processes. In a steady-state, the heat transfer coefficient increased with the rise of the refrigerant charge. In the dynamic dissipating process, both heat flux and heat transfer coefficient decreased rapidly after the critical heat flux, and the surface temperature drop point of each refrigerant charge was presented. The optimum refrigerant charge was provided considering the cooling parameters and the system operating performance. When the refrigerant operating pressure was 0.5 MPa, the spray cooling process presented with the higher heat flux, heat transfer coefficient, and cooling efficiency in this experiment. Meanwhile, the suitable surface temperature drop point and more gentle heat flux curves in the nucleate boiling region were obtained. The research results will contribute to the spray cooling system design, which should be operated before departure from the nucleate boiling point for avoiding cooling failure.

Published
2021

6. Experimental investigation of aircraft spray cooling system with different heating surfaces and different additives

Author

Zhang Yang, Nianyong Zhou, Yanlong Jiang, and Yu Wang

Subjects
Materials science, Critical heat flux, 020209 energy, Energy Engineering and Power Technology, Thermodynamics, 02 engineering and technology, Heat transfer coefficient, 01 natural sciences, Industrial and Manufacturing Engineering, 010305 fluids & plasmas, Corrosion, chemistry.chemical_compound, Flux (metallurgy), chemistry, Experimental system, 0103 physical sciences, Heat transfer, 0202 electrical engineering, electronic engineering, information engineering, Water cooling, Composite material, Ethylene glycol
Abstract

As an efficient cooling method for high heat flux, spray cooling has a great application potential on aircraft directed energy weapon cooling. Based on the analysis of previous research results, an experimental system of open loop spray cooling was established. Four different surfaces and two additives were applied and spray cooling performance including surface heat flux, surface temperature and heat transfer coefficient was experimentally investigated with water as the cooling medium. The experimental results indicate that among the four surfaces, drilling surface has the highest heat transfer coefficient and combined surface has the highest cooling efficiency. Meanwhile heat transfer can be enhanced by adding potassium chloride to a certain concentration and then deteriorated with higher concentration; heat transfer is deteriorated with the increase of ethylene glycol concentration. Therefore for aircraft spray cooling system combined surface should be applied for its advantages of low surface temperature and high cooling efficiency while ethylene glycol is preferred to improve the application range of the system in consideration of the corrosion of salt solution.

Published
2016

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