Influence of the number of reynolds on the convective coefficient in heat exchangers type concentric tubes

Abstract

Objective. Determine the influence of the flow rates, both hot and cold, in the Global Coefficient of Heat Transfer and in the effectiveness of heat exchangers of concentric tubes and tube -shell, in a test bench brand GUNT model WL 110.

Material and methods.The test bench records the temperatures of cold and hot flows, as well as the heat fluxes through the walls. In addition, the flow rates (liters / min) of both flows can be modified. The present investigation is of experimental character in the pre experimental category, because during the investigation the study variables will be altered to criterion, in addition it is of the quantitative type because the tests will be carried out with a series of data to be processed.

Results.We can see that as the Reynolds number increases, and changes from laminar to turbulent, the convective coefficient of the hot flow increases by a smaller percentage, but the cold flow, the increase is more noticeable from 0.264 to 2.19 kW / mK, if the flow is parallel. For the countercurrent flow the behavior has the same tendency, but in this case the increase in the cold flow is of lower percentage.

Conclusion: We can say then that the Reynolds number has a significant influence on the convective coefficient, operating the exchanger in parallel or countercurrent.