Plate heat exchangers can achieve heat exchange with cold and hot media. In most cases, convection heat exchange is used. Plate heat exchanger accessories must be selected so that liquid-liquid exchange can be achieved instead of liquid. There is radiation heat transfer.
Convection heat transfer is the basic way of heat transfer. For heat transfer in working conditions, the liquid is always in contact with the wall. Therefore, the transfer of heat is through the continuous movement and mixing of the fluid, which is called convection; the second is the heat conduction caused by the fluid and the wall surface and the temperature difference between the fluid. Such a process in which convection and heat conduction occur simultaneously is called convective heat transfer.
Because the two medium heat exchanger parts have different flow powers, the convection heat exchange conditions will be very different. Convection heat transfer can be divided into two categories. One is natural convection heat transfer, which is the flow heat transfer caused by the difference in the density of each part of the two media; the other is forced convection heat transfer, where the fluid is Heat exchange caused by flow under external forces such as pumps or fans.
In fact, there are many factors that affect the heat transfer of the medium. The heat exchanger accessories manufacturers introduce the physical properties of the medium, such as specific heat, thermal conductivity, density, viscosity, etc., as well as the shape, size, and flow of the fluid. All will affect convective heat transfer, and the situation is usually more complicated.
