Numerical Investigation of a Tubular Heat Exchanger Fitted with Triangular Ribs

Abstract

In the present work we numerically study the effect of the presence of triangular shaped promoters on the efficiency of a tubular heat exchanger. When we talk about efficiency, we are generally faced with problems of dynamic and thermal behavior within the latter. The main objective is to optimize the geometric parameters of the triangular-shaped promoters in order to collect the maximum energy at a minimum cost. Indeed, in the case of a two-dimensional simplified geometry, we considered the flow of an incompressible fluid (air) in a cylindrical heat exchanger tube equipped with baffles placed perpendicular to the direction of flow. Several baffle arrangements are considered according to the angle of inclination β, the space between the two successive baffles (space ratio PR: P/Dh) and the length of the baffle (blocking ratio BR: e/Dh) . The calculations are carried out by means of the fluent computer code using the k-ε turbulence model, RNG, with a Reynolds number Re varying from 3000 up to 13000. The results found indicated that the best thermal performance obtained corresponds to β=30°;BR=0.2; PR=1 and Re=4000.

Keywords

• Turbulence ribs
• Nusselt number Nu
• Friction number Fr
• Turbulence model K-ε RNG
• Thermalhy