Cooling of a Finned Cylinder by a Jet Flow of Air

Abstract

A submerged slot jet of air is used to cool an externally finned cylinder, heated by electric current. The cylinder ensemble is made of a stainless steel finned tube and a Teflon bar core inside. Five thermocouples, pressed inside the steel tube by the Teflon bar, measure the wall temperature to determine local and mean convective heat transfer coefficients. The local Nusselt number has the maximum on the impinging point and the minimum on the rear point. The variation of local and mean Nusselt numbers with the distance from the slot exit is investigated. Empirical expressions are proposed to correlate the experimental data. The cooling of a finned cylinder with a jet flow realizes a higher heat transfer as compared to a smooth cylinder.

Passive scalar diffusion in three-dimensional turbulent rectangular free jets with numerical evaluation of turbulent Prandtl/Schmidt number

“…This work extends the 2D approach, employed in [51], showing that with the 3D approach it is possible to define a new theory for the diffusion of the passive scalar in the FDR. which is important to be used as input in the RANS modeling for computing the heat transfer in a jet impinging a single smooth cylinder [56][57][58][59][60][61][62], a finned cylinder [63][64][65][66][67], two [68,69] and three cylinders in a row [70,71].…”

Further results on the mean mass transfer and fluid flow in a turbulent round jet

“…Results presented in this paper need to be taken into account in modelling mean turbulent jet flow in URF and PCR regions, which is very important in the evaluation of heat transfer in a jet which impinges obstacles, e.g. cylinders, [50][51][52][53][54][55][56][57][58][59][60].…”

Experiments and numerical simulations of mass transfer and flow evolution in transient rectangular free jet of air

“…The passive scalar diffusion in 3D turbulent rectangular free jets has been investigated with the numerical evaluation of the turbulent Prandtl/Schmidt number in fluids with laminar Schimdt number equal to 1 [31] and smaller than 1 [32]. The numerical prediction of the transient flow evolution can be of great importance in the heat and mass transfer of a jet impinging on a single smooth cylinder [33][34][35][36][37], a finned cylinder [38][39][40][41][42], two [43] and three cylinders in a row [44].…”