2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Ketan Atulkumar Ganatra ◽  
Dushyant Singh

The numerical analysis for the round jet impingement over a circular cylinder has been carried out. The v2f turbulence model is used for the numerical analysis and compared with the two equation turbulence models from the fluid flow and the heat transfer point of view. Further, the numerical results for the heat transfer with original and modified v2f turbulence model are compared with the experimental results. The nozzle is placed orthogonally to the target surface (heated cylindrical surface). The flow is assumed as the steady, incompressible, three-dimensional and turbulent. The spacing between the nozzle exit and the target surface ranges from 4 to 15 times the nozzle diameter. The Reynolds number based on the nozzle diameter ranges from 23,000 to 38,800. From the heat transfer results, the modified v2f turbulence model is better as compared to the other turbulence models. The modified v2f turbulence model has the least error for the numerical Nusselt number at the stagnation point and wall jet region.


2007 ◽  
Vol 129 (4) ◽  
pp. 411-420
Author(s):  
Y. C. Lee ◽  
C. J. Fang ◽  
M. C. Wu ◽  
C. H. Peng ◽  
Y. H. Hung

An effective method for performing the thermal optimization of stationary and rotating multichip module (MCM) disks with an unconfined round-jet impingement under space limitation constraint has been successfully developed. The design variables of stationary and rotating MCM disks with an unconfined round-jet impingement include the ratio of jet separation distance to nozzle diameter, Grashof number, jet Reynolds number, and rotational Reynolds number. The total experimental cases for stationary and rotating MCM disks are statistically designed by the central composite design method. In addition, a sensitivity analysis, the so-called analysis of variance, for the design factors has been performed. Among the influencing parameters, the jet Reynolds number dominates the thermal performance, while the Grashof number is found to have the least effect on heat-transfer performance for both stationary and rotating cases. Furthermore, the comparisons between the predictions by using the quadratic response surface methodology and the experimental data for both stationary and rotating cases are made with a satisfactory agreement. Finally, with the sequential quadratic programming technique, a series of thermal optimizations under multiconstraints—such as space, jet Reynolds number, rotational Reynolds number, nozzle exit velocity, disk rotational speed, and various power consumptions—has been systematically explored and discussed.


Author(s):  
Haibo Ma ◽  
Justina Lee ◽  
Rui Liu ◽  
Michael Lowry ◽  
Armin Silaen ◽  
...  

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