Archive | 2021
Experimental Study of The Augmentation of Convection Heat Transfer in Horizontal Circular Tube Using Tripping Wires Inserts.(Dept.M)
Abstract
The\xa0work summarizes\xa0the results of the exp erimental investigation of convective\xa0heat\xa0transfer\xa0and\xa0pressure loss characteristics\xa0of air flow in horizontal circular copper tube of diameters 133/22 mm. The coil wire (with diameter of 1.4 mm) was inserted in the\xa0tested tube.\xa0The helix angle changed from\xa04.26oc to 30.78°. The outer\xa0surface of the tube was\xa0heated\xa0by a\xa0little superheated steam (2-3°C)\xa0at\xa0one atmosphere. During the\xa0experimental work, Reynolds number changed from 60\xa0to 4000 and Prandtl number\xa0was about 0.7. The enhancement of\xa0heat\xa0transfer for the tested tube\xa0with internal coils was higher\xa0than that of the bare tube\xa0by about\xa057%. However,\xa0a\xa0quantitevely increase in hydrodynamic\xa0resistance was noticed. Correlation of Nusslet number and friction coefficient has been made. It was found that the Nusslet number was strongly dependent nn Reynolds number,\xa0wherase the friction coefficient is dependant on helix angle as\xa0well as Reynolds number.