Hofmann (Beijing) Engineering Technology Co.,Ltd
Add:6F, East International Building, No.2 DongZhiMen Outside Street, DongCheng District, Beijing
The plate heat exchanger is an efficient and compact heat exchange device. Although its development has been nearly a hundred years old, and it has a wide range of applications in the national economy (such as food, pharmaceutical), but due to temperature, pressure, corrosion resistance, its comprehensive promotion and application in various departments . Since the 1980s, due to the continuous advancement of manufacturing technology, gasket materials and the continuous improvement of heat transfer theory, the application of plate heat exchangers has received more and more attention from the industrial production department.
To determine whether a new enhanced heat transfer technology is advanced, it must be evaluated. However, in actual use, a variety of methods and evaluation indicators for evaluating heat transfer have emerged. Some people advocate the use of the ratio of the heat exchange amount Q to the power N of the pump (or fan) consumed, that is, the energy coefficient is used as an evaluation index, and similarly, K/ΔP and non-differentiated Nu/ζ are widely used for evaluation. More accurately reflecting the performance of heat transfer enhancement, K/ΔP1/3 and Nu/ζ1/3 can be used as indicators. With the development of heat transfer technology, heat exchangers are increasingly moving toward small size and light weight, and at the same time, operating costs are reduced on the premise of improving efficiency. On the basis of comprehensive analysis, a set of relatively complete performance evaluation data is proposed, that is, the two factors of maintaining the transmission power, heat transfer area and heat transfer load are unchanged, and the size of the third factor is compared to evaluate the heat transfer performance. Good or bad.
These evaluations only analyze the quantity, transfer, utilization and loss of the energy of the heat exchanger, that is, based on the first law of thermodynamics. In order to more accurately reflect the loss of energy in the heat exchange process, many evaluation methods based on the second law of thermodynamics are also proposed in the theoretical research, that is, the analysis of the conversion, transmission, utilization and loss of the fire in the heat exchanger. . When the technology is promoted and applied, it should also consider the increase of the price of the pipe and the change of the operating cost after the heat transfer enhancement technology, and use the economic accounting method to evaluate, that is, the evaluation method of thermal economics.
In the actual use process, the research on new heat transfer technology and new method is carried out by using simple and easy-to-use single parameter K, ΔP and single parameter K/ΔP, K/ΔP1/3 for evaluation. [9~11]. The method based on the second law of thermodynamics can be used to judge the performance of the heat exchanger in the design process as a basis for further improvement, but it lacks practicality in engineering.