Experimental Investigation On Flow And Heat Transfer Feature Of Tube-fin Heat Exchanger

As a device of transferring heat energy, heat exchangers can be of many types.according to the structural forms can be divided into plate heat exchanger, tube heatexchanger, extended surface heat exchanger and regenerator, etc.With its large heatexchange area and small volume, the tube-fin heat exchanger has been widely used inthe many fields of modern science, such as refrigeration, air conditioning, automotiveand air cooling, computer schedule etc. The heat exchanger performance of tube-finheat exchanger is influenced by many factors, such as fin structure, fin pitch, pipediameter size row of tubes and fouling, etc, and the fin structure has the mostsignificant impact on the heat exchanger performance.According to the model test method which is based on the similar principles, twokinds of tube-fin heat exchangers with wavy fin and new type slotted fin weredesigned, experiment system was established, and studied the two kinds of heatexchangers’ performance by means of temperature test and heat transfer calculation,while the influence of fin structure on heat transfer efficiency was analyzed.The experiment use water and air for two kinds of heat exchanger to heattransfer,experiment proceeded under21st different condition. The followingconclusions can be reached:(1) With the water flow is constant, the average heattransfer capacity and overall heat transfer coefficient of the two kinds of heatexchangers increase linearly with airflow increasing, and the heat transfer coefficientof wavy fin-and-tube heat exchanger is higher than41.25%of the slotted fin-and-tubeheat exchanger（;2）Comparison structures of two fin-tube, the smaller diameter of thecorrugated fins, the fewer number of tube rows, in the same conditions, the heattransfer coefficient in water phase of the corrugated fin tube heat exchanger is20%more then the slotted fintube heat exchanger;(3) Under the minimum water flow rateand maximum air flow conditions, the heat transfer coefficient in air phase of the newslotted fin and tube heat exchanger is9.7%higher than the corrugated fin and tubeheat exchanger;(4) The drag coefficient in air phase of two heat exchangers decreasewith increases of Re, but the drag coefficient of the slotted fin and tube heatexchanger is7.7%to3.4%higher than the corrugated fin and tube heat exchangerunder the air flow rate within the0.011m3/s~0.044m3/s occasion.In conclusion thenew type slotted fin-and-tube heat exchanger can effectively enhance the heat transfercoefficient of air part., From the comprehensive said the overall performance of thecorrugated fin and tube heat exchanger is superior to the open seam finned tube heatexchanger.