Numerical study of forced convection in wavy and diverged-converged ducts

Abstract EN

A three-dimensional study of developing fluid flow and heat transfer through wavy and diverged-converged ducts were studied numerically for a Prandlt number 0.7 and 5.85 and compared with flow through corresponding straight duct.

The Navier- Stokes and energy equations are solved by using control finite volume method.

Development of the Nusselt number in wavy and diverged-converged ducts are presented for different flow rates (50 < Re < 300), height ratio (Hmin / Hmax = 0.46, 0.39 and 0.33) for diverged-converged duct and length ratio (L / 2a = 10, 6.67 and 5) for wavy duct.

In the two types of ducts, the local Nusselt number increases with increasing of Reynolds number but decreases with decreasing height ratio or length ratio.

In the diverged-converged duct at Pr = 0.7 the maximum average Nusselt number takes place at height ratio (Hmin / Hmax = 1) but it becomes minimum at Pr = 5.85.

The results shown that the best of heat transfer takes place at wavy duct compared to the diverged-converged duct when air heat exchanger is used.

The water heat exchanger performance was found to be approximately similar for both ducts.

There is good agreement between the results of this work with the corresponding numerical results presented by Bahaidarah et.

al [9].