Investigation Of The Exergy Transfer Characteristics In The Plate Heat Exchanger

In recent years, the excessive exploitation and utilization of resources cause serious pollution of environment. It is a serious problem in our country. To use resources and improve the utilization rate of resources is an important topic all over the world. As a kind of important equipment for the efficient use of energy, heat exchanger is widely used in industrial production and food processing field. Although many scholars have a lot of research on heat transfer performance of plate heat exchanger, using the exergy transfer theory study of plate heat exchanger is less. In this paper, the exergy transfer theory is used to compare heat transfer and exergy transfer for two kinds of evaluation method in plate heat exchanger.First, the mainsream of the plate heat exchanger is determined in GAMBIT. A three-dimensional numerical model of plate hrat trsnsfer elements has been set up and meshed in FLUENT, obtaining the element's internal flow field and temperature field distribution. By numerical simulations on models of different corrugated angle and corrugated pitch, the regulation that hest transfer performance Nu number and heat transfer coefficient of response element changed with inclination angle and pitch of corrugations have been obtained. Then, becaused of deriving the exergy effectiveness and exergy transfer coefficient calculation formula of corrugated calculated with different angel and different corrugating pitch, the exergy effectiveness and exergy transfer coefficient have been calculated. The differences and similarities between the two criteria of heat transfer and exergy transfer are compared. Finally, the water and oil have been carried on the numerical simulation and compared by using the theory of exergy transfer.Research results show that:(1) For different corrugated angle in hot plate, the nusselt number and the heat transfer coefficient increases with the increasing corrugated angle; When corrugated angle is about 70 °, the nusselt number achieves maximum value;With corrugated angle continuing to increase, the nusselt number and the heat transfer coefficient decrease gradually.(2)For the different corrugating pitch in hot plate, with the increasing of corrugating pitch, nusselt number and the heat transfer coefficient decrease.(3)According to different corrugated and different corrugated pitch angle, the exergy effectiveness,the change trend of exergy transfer coefficient,nusselt number and thechange trend of heat transfer coefficient are consistent. But the average exergy transfer coefficient is smaller than the heat transfer coefficient.(4)The change trend of exergy effectiveness and exergy transfer coefficient for oil are consistented with the change trend of water, but the value is smaller than that of the water.