HEAT TRANSFER CHARACTERISTICS OF A HORIZONTAL CYLINDER UNDER IMPINGMENT OF LAMINAR UPWARD-DIRECTED SLOT JET FLOW

Author(s):  
Shahin Amiri ◽  
Kaveh Habibi ◽  
Mehdi Ashjaee
1999 ◽  
Vol 121 (2) ◽  
pp. 341-348 ◽  
Author(s):  
H. S. Sheriff ◽  
D. A. Zumbrunnen

Recent investigations have revealed that pulsations in an incident jet flow can be an effective technique for modifying convective heat transfer characteristics. While these studies focused on single impinging jets, industrial applications of impinging jets usually involve arrays of jets. To explore the effects of flow pulsations on the heat transfer performance of jet arrays, an experimental investigation has been performed of instantaneous and time-averaged convective heat transfer to a square, in-line array of circular air jets within an unit cell of the array. Hot-film anemometry was used to document the jet flow field. Instantaneous and time-averaged convective heat transfer rates were measured using a heat flux microsensor. An ensemble averaging technique was used to separate the pulsating component of flow velocity and heat transfer from the turbulent components and thereby assess the effect of flow pulsation on turbulence intensity and heat transfer. For the ranges of parameters considered, results indicate convective heat transfer distributions become more uniform in response to pulsations but heat transfer is not enhanced. Improved uniformity can be a useful aspect in many jet applications.


Author(s):  
Sushil Kumar Rathore ◽  
Manab Kumar Das

The numerical simulation of turbulent offset jet flow has been carried out using k–ω shear stress transport (SST) model. The simulations have been done for the offset jet flow in the quiescent medium and also in the presence of an external stream. The effect of freestream velocity on the flow and heat transfer characteristics of turbulent offset jet has been reported. The offset ratio and Reynolds number of flow considered are 5.7 and 16,000, respectively. The presence of coflow stream has been found to reduce the entrainment of surrounding fluid into the jet which in turn reduces the heat transfer from the jet to the surrounding medium. The effect of freestream velocity on the important parameters like decay of the local maximum streamwise velocity, jet spread, reattachment length, velocity logarithmic profile, velocity defect law profile, decay of the local maximum streamwise temperature, variation of wall temperature, temperature similarity profile, and Nusselt number distribution has been discussed.


Sign in / Sign up

Export Citation Format

Share Document