Study of fully-developed turbulent flow and heat transfer in a rotating wavy-walled duct

Author(s):  
Abhishek G. Ramgadia ◽  
Arun K. Saha
Author(s):  
Sassan Etemad ◽  
Bengt Sunde´n

The turbulent flow and the heat transfer in a unitary cell of a cross corrugated plate pattern heat exchanger has been studied using Chen’s high-Re k-ε model, Suga’s low-Re k-ε model, the RSM and the V2F model at a Reynolds number of 4930. The ability of these models in predicting the mean Nusselt number and Fanning friction factor has been investigated. The V2F model predicted higher heat transfer and friction factors than the other models. It was observed that the upper and lower flow in the unitary cell interact throw a shear process. This in turn initiates a complex secondary flow pattern which promotes the heat transfer. The V2F model predicted the strongest shear process. This may explain the fact that it also predicted the highest values of heat transfer and friction factor compared to the other models. The shear flow also caused high levels of turbulent kinetic energy in the centre of the unitary cell. The observed secondary motion is believed to be an efficient means of increasing the heat transfer coefficient with limited pressure drop penalty. It is also demonstrated that despite the geometrical complexity, high quality computational grids can be created and thereby details of the flow and heat transfer phenomena can be studied. The RSM appeared to be instable and gave results similar to Chen’s k-ε model. Therefore, its use is not motivated for such applications.


1979 ◽  
Vol 101 (1) ◽  
pp. 29-37 ◽  
Author(s):  
S. V. Patankar ◽  
M. Ivanovic´ ◽  
E. M. Sparrow

The fully developed turbulent flow and heat transfer characteristics for tubes and annuli with longitudinal internal fins were analyzed via a mixing length model. The model takes account of the proximity of both the fin surfaces and the tube wall as well as of the gradients in the radial and circumferential directions. Application was made to air flows, and a single adjustable constant in the model was fixed by comparisons with experimental data for the friction factor and the circumferential-average Nusselt number for internally finned tubes. The local heat transfer coefficients exhibited a substantial variation along the fin height, with the smallest value (essentially zero) at the base and the largest value at the tip. Lesser and more gradual variations were exhibited by the local heat transfer coefficients on the wall of the tube or annulus. In general, the fins were found to be as effective a heat transfer surface as the wall (per unit area). Average Nusselt numbers and friction factors are presented for both the tube and the annulus.


1988 ◽  
Vol 74 (1) ◽  
pp. 95-110 ◽  
Author(s):  
HIDEOMI FUJITA ◽  
HAJIME YOKOSAWA ◽  
MASAFUM HIROTA ◽  
CHIKAYUKI NAGATA

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