Heat exchanger is an indispensable and important equipment in industrial production, and its main function is to change the temperature of the fluid through heat transfer. The working principle of heat exchangers is based on the second law of thermodynamics, which states that heat always flows spontaneously from hot objects to low temperatures.
In a heat exchanger, two or more fluids of different temperatures come into contact and exchange heat through the wall. High-temperature fluids transfer heat to low-temperature fluids for the purpose of cooling or heating. This heat transfer process can be either direct contact (e.g. in shell-and-tube heat exchangers) or indirect contact (e.g. in plate heat exchangers).
The design and selection of a heat exchanger requires consideration of several factors, including the nature of the fluid, flow rate, temperature differences, pressure drop, and the cost and maintenance requirements of the heat exchanger. Common types of heat exchangers are shell-and-tube heat exchangers, plate heat exchangers, finned tube heat exchangers, casing heat exchangers, and spiral plate heat exchangers.
In general, heat exchangers are widely used, covering many fields such as chemical industry, energy, food, medicine, and environmental protection. Understanding and mastering the basic principles of heat exchangers is of great significance for optimizing the production process and improving energy efficiency.