Wei Zhong

Bio: Wei Zhong is an academic researcher from Southwest Jiaotong University. The author has contributed to research in topics: Thermal energy storage & Heat transfer. The author has an hindex of 1, co-authored 1 publications receiving 2 citations.

The thermal performance of an ethanol solar still with fin plate to increase productivity

Abstract: This article presented an indoor experiment on developing a mathematical model for predicting the productivity of an ethanol solar still of basin type. The test still contained a horizontal evaporating surface and a condensing surface inclined 14° to a horizontal. Various concentrations of ethanol–water solution were employed for this experiment. The distillation temperature range included boiling point. The collected data were used to estimate the mass-transfer coefficient and mass transfer conductance of the solar still. Accordingly, a mathematical model was developed based on the Spalding theory of convection and the Fick's law of diffusion. In order to increase the performance at the outdoor conditions, a basin solar still was integrated with a set of fin-plate fitting in the still basin for distillation of a 10%v/v alcohol solution. It was found that the productivity of the modified solar still was increased by 15.5%, compared to that of a conventional still. Moreover, the predicted still efficiency by the model could increase to 46% when a number of fins that raised an effective absorptance were increased. Condition of high concentration output and high productivity was investigated. Monthly mean productivity and efficiency of the still were found to increase with daily mean insolation.

Heat transfer performance of a finned shell-and-tube latent heat thermal energy storage unit in the presence of thermal radiation

Abstract: • Uncovered the influence mechanism of thermal radiation on melting process. • Radiation increases the interface length and enhances the melting of the lower part. • A maximum enhancement in liquid fraction by radiation is 7.9% for the base case. • Enhanced melting rate by reducing fin angle or rising fin length and fin number. • The role of thermal radiation weakens with an increase of fin length or fin number. Phase change materials can emit and absorb radiation, so the role of thermal radiation on melting process becomes prominent with the recovery of medium-high temperature waste heat and the development of concentrating solar power. In the study, a numerical analysis on the heat transfer performance of finned shell-and-tube latent heat thermal energy storage (LHTES) units was conducted where the influence characteristics and mechanism of thermal radiation were particularly emphasized. Also the effect of three fin parameters was examined. Results show that the radiation heat transfer rate is nearly one order of magnitude smaller than total heat transfer rate. However, thermal radiation lengthens the phase interface length and enhances the heat transfer of the lower part, accelerating the melting process considerably, with the liquid fraction enhanced by 7.9% and melting time shortened by 23.3% for the base case. The increase of fin length or fin number weakens the role of thermal radiation. As fin number increases from 4 to 48, the maximum radiation enhancement factor reduces from 7.3% to 1.2%. A fin structure with the angle of 0°, dimensionless length of 1.0 and number of 48 is recommended for improving the heat transfer performance of shell-and-tube LHTES units.

Experimental investigation on thermosyphon aid phase change material heat exchanger for electronic cooling applications

Abstract: In this work, cooling of electronic modules is experimentally investigated using a thermosyphon aid phase change material (PCM) heat exchanger with different thermic fluids such as n-hexane, benzene and DI water respectively. The experiments are conducted simultaneously by evaluating the thermal performance of thermic fluids and heat power stored by PCM for various heat inputs ranging from 70 to 110 W. At high heat input conditions, the value of low thermal resistance, maximum convective heat transfer coefficient (CHTC) and percentage of heat extraction of n-hexane are 0.350 K/W, 185.53 W/m2K and 99.2% respectively. Low enthalpy of vapourization and a high degree of superheat is the criteria for the obtained results. Also, temperature variation in PCM during melting is analysed by the influence of vapourized thermic fluids for different heat inputs. The maximum heat power stored by PCM is found as 7.78 W for vapourized n-hexane at 110 W due to high mass flow rate and less time for reaching steady-state temperature (SST) of PCM. The solidification of PCM is noted using cold water at regular time intervals during power-off conditions and observed that n-hexane influenced molten PCM takes 25 min for complete solidification.