Flow Distribution Characteristics In The Tubes Of Tube And Fin Heat Exchanger

Tube-and fin heat exchanger as the core equipment of power system and industrial process.Due to its unique advantages and practicality,it is widely used in many fields With the large use of tube and fin heat exchangers,their ability and realiability issues are getting more and more attention.Among them,the flow distribution problem of the tube and fin heat exchanger is particularly prominent because it is directly related to the heat exchange,efficiency,safety and economic problems of the equipment.This paper takes a tube and fin heat exchanger as the research object,study the flow characteristics of fluids in heat exchangers and the factors affecting flow characteristics through experimental methods.The heat exchanger studied is a heat exchanger with a double-flow channel structure,the flow distribution in two flow channels(high temperature channel and low temperature channel)was measured under the same heat exchanger water cap structure size and inlet conditions analyze experimental data,change the diameter and number of holes in the cap of the heat exchanger orifice,and discuss the influence of the diameter and number of the opened in water cap on flow distribution.The experimental data is sorted,compared,and analyzed,and then the following results are obtained(1)When the flow rate is small,the flow rate of the fluid in the tube decreases continuously along the direction of the average flow of the fluid inside the water cover of the heat exchanger.When the flow rate is large,there is a backflow phenomenon at the end of the average flow direction of the fluid inside the water capr of the heat exchanger water cover,which causes the flow rate rising in the tube at the end of the water cap of the heat exchanger to rise.Under the same structure,as the inlet flow rate increases,the maximum flow deviation coefficient increases,indicating that the flow distribution uniformity is deteriorated,and the inlet pressure of the heat exchanger is continuously increased.(2)After analyzing and comparing the experimental date of the flow distribution at condition without changing the structure and the data of changing the diameter of the holes of the water cap of the heat exchanger,it is found that the experimental maximum flow deviation coefficient after changing the diameter is lower than that before the d diameter unchange,so the heat exchanger flow distribution after the variable diameter is more uniform,indicating that the orifice water outlet diameter is an important factor affecting the heat exchanger flow distribution.(3)Keeping the pore diameter unchanged,increase the number of the holes in the water cap plate of the heat exchanger,comparing the experimental data,it is found that the maximum flow deviation coefficient after changing of the number of the holes is furtherreduced,therefore,the number of the holes in the heat exchanger water cap is also an important factor in the flow distribution of the heat exchanger.At the same inlet flow rate,the inlet pressure of the heat exchanger is larger than that before the number of the holes and the diameter of the holes are changed.(4)For heat exchanger by using the method of numerical analysis to simulate the internal flow characteristics of discovery: for distribution header,fluid on the header axis flow direction,fluid velocity,decrease of static pressure rising,the convergence of for the header,fluid on the header axis flow direction,fluid flow rate rising,static pressure and decreases.