An Experimental Study on Heat Transfer and Pressure Drop of Air-Solids Turbulent Flow inside a Horizontal Tube with Different Entrance Angles.

Document Type : Research Studies

Authors

Mechanical Power Engineering Department., Shoubra Faculty of Engineering., Zagazig University.

Abstract

The present work deals with The effect of turbulent air-sand suspension flow on heat transfer and  pressure drop in horizontal tube with a uniform heat flux at different entrance angles. four different  inlet bend angles in addition to the case of plain tube (θ=oo were studied at different Reynolds  numbers, sand particles of different average-sizes and different mass loading ratios.  
It was obtained for the plain tube flow that the presence of the solid particles in turbulent flow  enhances the heat transfer coefficient giving an enhancement ratio of the Nusselt number of 1.'5 at  M=O.4 and Re=35,000 for particles of 120 microns. Moreover, at higher Reynolds numbers (over  64, 000 slightly enhancement in the heat transfer coefficient was observed. For the flow with different  entrance angles. the heat transfer coefficient enhances in the upstream portion of the fest-section. The  results of clean-air flow show that about 1.18 fold increase in average Nusselt number was  corresponding to about 1.5 fold increase in the pressure drop along the test-section. The presence of  the solid particles in the flowing air enhances the heat transfer coefficient up to mass-loading ratio of  M=O.15 and further addition of solids affects slightly the heal transfer coefficient.  
New correlations for the Nusselt number and its enhancement ratio were obtained for both cases of  plain tube and for the tube with different entrance angles.  

Main Subjects

MEJ- Mansoura Engineering Journal
Volume 20, Issue 2
VOL 20 has Two Issues Issue 2 Consist of Two Parts from ( March to June)
June 1995
Pages 25-37

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