Yang Chunxin

Three-dimensional heat transfer analysis for a thermal energy storage canister

High temperature latent thermal storage is one of the critical techniques for a solar dynamic power system. This paper presents results from heat transfer analysis of a phase change salt containment canister. A three-dimensional analysis program is developed to model heat transfer in a PCM canister. Analysis include effects of asymmetric circumference heat flux, conduction in canister walls, liquid PCM and solid PCM, void volume change and void location, and conduction and radiation across PCM vapor void. The PCM phase change process is modeled using the enthalpy method and the simulation results are compared with those of other two-dimensional investigations. It’s shown that there are large difference with two-dimensional analysis, therefore the three-dimensional model is necessary for system design of high temperature latent thermal storage.

Reexamination of correlations for nucleate site distribution on boiling surface by fractal theory

Nucleate site distribution plays an essential role in nucleate boiling process. In this paper, it is pointed out that the size and spatial distribution density of nucleate sites presented on real boiling surface can be described by the normalized fractal distribution function, and the physical meaning of parameters involved in some experimental correlations proposed by early investigations are identified according to fractal distribution function. It is further suggested that the surface micro geometry characteristics such as the shape of cavities should be described and analyzed qualitatively by using fractal theory.

Analysis of heat transfer behaviour of the conduction cold plate system

The heat-transfer behaviour of the conduction cold plate system used for avionics is investigated in this paper. The steady-state temperature profile for the cold plate is derived and the relationship between the coolant mass flowrate, the heat load and the highest cold plate temperature is established. A model is proposed to describe the transient thermal rosponse of the cold plate under thermal shock condition. The analytic solution of the transient heat transfer within the cold plate is provided. The results of this paper agree with those of the finite element method and can be used for the structural design and performance evaluation of cold plate system.The heat-transfer behaviour of the conduction cold plate system used for avionics is investigated in this paper. The steady-state temperature profile for the cold plate is derived and the relationship between the coolant mass flowrate, the heat load and the highest cold plate temperature is established. A model is proposed to describe the transient thermal rosponse of the cold plate under thermal shock condition. The analytic solution of the transient heat transfer within the cold plate is provided. The results of this paper agree with those of the finite element method and can be used for the structural design and performance evaluation of cold plate system.

Determination of a vapor compression refrigeration system refrigerant charge

A physical model is established in this paper to describe the heat transfer and two phase flow of a refrigerant in the evaporator and condenser of a vapor compression refrigeration system. The model is then used to determine the refrigerant charge in vapor compression units. The model is used for a sensitivity analysis to determine the effect that varing design parameters on the refrigerant charge. The model is also used to evaluate the effect of refrigerant charge and the thermal physical properties on the refrigeration cycle. The predicted value of the refrigerant charge and experimental data agree well. The model and the method presented in this paper could be used to design vapour compression units such as domestic refrigerators and air conditioners.A physical model is established in this paper to describe the heat transfer and two phase flow of a refrigerant in the evaporator and condenser of a vapor compression refrigeration system. The model is then used to determine the refrigerant charge in vapor compression units. The model is used for a sensitivity analysis to determine the effect that varing design parameters on the refrigerant charge. The model is also used to evaluate the effect of refrigerant charge and the thermal physical properties on the refrigeration cycle. The predicted value of the refrigerant charge and experimental data agree well. The model and the method presented in this paper could be used to design vapour compression units such as domestic refrigerators and air conditioners.