Heat exchanger design

I. 1. Structure； 2. Medium ； 3. Operating parameters: II. The value of the heat transfer coefficient is influenced by various factors such as the properties of the hot and cold fluids, the operating conditions of heat exchange (such as flow rate and temperature), the degree of fouling on the heat transfer surfaces, as well as the structure and size of the heat exchanger. Convective heat transfer is very complex, and the thermal resistance of the fouling layer is difficult to determine; as a result, the calculated values of the heat transfer coefficient often differ significantly from the actual values. When designing heat exchangers, it is best to have measured values or empirical data accumulated from production as a reference. III. The overall heat transfer coefficient of a heat exchanger is primarily related to the film heat transfer coefficients on both sides of the heat transfer tubes as well as the thermal resistance of those tubes. Therefore, the overall heat transfer coefficient of a heat exchanger is dependent on the following parameters: Now you should understand the importance of determining the heat transfer coefficient K

The problem seems simple. It’s hard to answer. I’d better read by myself.

It seems that first an heat transfer coefficient is determined based on experience, and then the design is carried out. The heat transfer coefficient of the resulting heat exchanger is compared with the one initially determined; if there is a significant difference, the design is revised. It means that without a heat transfer coefficient, it is impossible to carry out the design; one must first assume a value and then use trial and error methods.