Theoretical And Experimental Research On The Surface Performance Of Wavy Fin Of Plate Fin Heat Exchanger In Air Separation Plants

Due to its advantages of high compactness, large heat transfer area per volume and light-weight, compact heat exchangers (CHE) were greatly employed in petroleum, chemistry, vehicle, fuel cell and cryogen industries. It was gradually replacing the tube and shell heat exchangers in recent decades. Plate fin heat exchanger (PFHE) is one form of compact heat exchangers. By adopting extended heat transfer areas, the plate fin heat exchanger showed favorable heat transfer ability. The accuracy and validity of plate fin heat exchanger thermal design process depended highly on the precise heat transfer and pressure drop performance data of the extended heat transfer area. Numerical and experimental research has been conducted on the wavy fin performance in this essay.Firstly, experiment research of two types of wavy fins is conducted in a wind channel test rig. Three test elements are manufactured to test the Colburn and Fanning factor under laminar, transitional and turbulent flow conditions for each different type of wavy fin. It was shown that the relative variation of three different elements test results was minimal. Further investigation of the test results imply the test results are of high accuracy and reliability.Secondly, the effect of geometric parameters on wavy fin pressure drop performance had been analyzed. The values of wavy amplitude and per unit flow length were combined based on the orthogonal design method to form different computational geometric models.CFD technology was applied to study the influence of the geometry on the wavy fin drag characteristic at specific flow pattern.Finally, based on the above conclusion, the influence of the wavy fin amplitude on the wavy fin overall performance factor was investigated at specified transitional flow pattern. By analyzing the temperature field and pressure distribution field of the models with same per unit flow length and different wavy amplitude structures, effect of the waviness on the heat transfer and pressure drop performance was respectively discussed. It could be concluded from the results that the wavy amplitude variation had large influence on the heat transfer and pressure drop performance of the wavy fin. Larger wavy amplitude led to higher Colburn factor as well as Fanning factor. However, as the wavy amplitude increased, the overall heat transfer performance factor grew smaller.In a word, experimental research on two types of wavy fins was conducted and theoretical research of the effect of the wavy severity and per unit flow length on the performance was performed. The work in this paper is of great engineering meaning for providing valuable guidance for developing new form of high performance wavy fins, prompting the efficiency of heat exchanger and reducing energy consumption.