内螺旋肋管流动与传热特性的实验研究

对六种内螺旋肋管进行了流动与传热的实验研究,实验管内径为16．25-16．69 mm,内螺旋肋高为0．28-0．44 mm,螺旋肋牙数为40-45,螺旋角为43°-45°．研究表明,内螺旋肋管可以有效地强化传热,本文所研究的管型的传热强化倍率为1．67-2．99．比较了两种评价内螺旋肋管性能的方法．用Webb模型及Ravigururajan模型对内螺旋肋管进行了性能预测并与实验值进行了比较．两个模型的预测值与本试验结果有较大偏差,相对而言,传热模型稍优．

EXPERIMENTAL STUDY OF FLUID FLOW AND HEAT TRANSFER IN INTERNAL HELICAL-RIB TUBES

Experimental study of fluid flow and heat transfer characteristics in six tubes with internal helical-rib has been conducted. The inside diameters of the studied tubes are 16.25 to 16.69 mm, rib heights 0.28 to 0.44 mm, number of rib 40 to 45, helix angles 43 to 45 deg. It is found that the internal helical-rib tube can effectively enhance heat transfer. The inner heat transfer coefficients of the studied tubes are 1.67 to 2.99 times more than that of smooth tube. A comparison of two methods for evaluating characteristics of internal helical-rib tube is conducted. The fluid flow and heat transfer characteristics are predicted by Webb model and Ravigururajan model, and compared with experimental data of internal helical-rib tube. It is found that the predicted results from the two models deviate appreciably from the present experimental data, with the heat transfer model being relatively better.