Study On Structure And Performance Of Heat Exchanger With Helical Baffles

The heat exchanger is a basic process equipment which has been widely used in a variety of industrial field including petrochemical engineering, energy and power, metallurgy, refrigeration and so on. Besides the important effects on the trouble-free operation and product quality control, its performance has been influenced by its energy consume and reliability. The shell-and-tube heat exchanger has been the most comprehensive heat transfer equipment because of its simple structure, fine heat transfer preference, sophisticated processing technique and excellent adaptability. But this kind of heat exchanger also has some disadvantages restricted by the configuration itself, especially for heat exchanger with segmental baffles, which accommodate: (1) the conventional baffles exhibit stagnated flow region that reduces heat transfer efficiency;(2) there has rather high pressure difference in shell side which increasing the pumping power requirement;(3) deposition of fouling cuts down the active time of exchanger;(4) bypass and leakage flow decrease the effective heat transfer ratio and (5) existing flow-induced vibration cause the exchanger to fail. Therefore, it has great benefit to develop a new design to eliminate these defects that will improve the operational lifetime of heat exchanger easily and have no destructiveness for the existing process conditions. The helical baffles offer a possible alternative to the segmental baffles by either circumventing or suppressing many of the aforementioned problems common to segmental baffles. The objective of this work is to study the helical baffles heat exchanger and compare its performance of heat transfer and pressure drop to the segmental baffles heat exchanger by numerical simulation and experiment test methods. The main contributions of the paper are as follows: (1) Helical baffles structure, complement and ensemble construction have been observed to gain the geometric design relationship for different helical baffles and its machining process, which can be used in plant-scale manufacture. In addition, there also have a preliminary research for design of double-shell-side heat exchanger with helical baffles. (2) A comparative work has been done between helical and segmental baffles heat exchanger to investigate its performance under different structure and operating parameters, which with a commercial CFD scheme. The result indicates that the helical baffles heat exchanger has a more favorable combined performance to the segmental baffles heat exchanger. (3) Design an experimental system for the performance test of heat exchanger with helical baffles. (4) The flow pattern, heat transfer and pressure drop characteristics for the shell side flow were studied to compare its work efficiency for helical and segmental baffles heat exchanger with alterable structure and operating parameters. (5) As an example, a sample heat exchanger with helical baffles was applied to Sinopec YANGZI Petrochemical Corporation to check the performance and reliability of helical baffles heat exchanger.