Experimental investigation of heat transfer and flow friction in a circular tube fitted with regularly spaced twisted tape elements

Abstract Experimental investigation of heat transfer and friction factor characteristics in a double pipe heat exchanger fitted with regularly spaced twisted tape elements, were studied. The inner and outer diameters of the inner tube are 50.6 and 25.8 mm, respectively and cold and hot water were used as working fluids in shell side and tube side. The twisted tapes were made of the stainless steel strip with thickness of 1 mm and the length of 1500 mm. They were inserted in the test tube section in two different cases: (1) full-length typical twisted tape at different twisted ratios (y = 6.0 and 8.0), and (2) twisted tape with various free space ratios (S = 1.0, 2.0, and 3.0). The results, obtained from the tube with twisted tape insert, were compared with those without twisted tape. The results show that the heat transfer coefficient increased with twist ratio (y). Whereas the increase in the free space ratio (S) would improve both the heat transfer coefficient and friction factor. The results from each case were correlated for Nusselt number and friction factor. Subsequently, the predicted Nusselt number and friction factor from the correlations were plotted to compare with the experimental data. It was found that Nusselt number was within ± 15% and ± 10% for friction factor.

[1]  V. Zimparov,et al.  Enhancement of heat transfer by a combination of three-start spirally corrugated tubes with a twisted tape , 2001 .

[2]  A. Date,et al.  Development of correlations for predicting characteristics of laminar flow in a tube fitted with regularly spaced twisted-tape elements , 1990 .

[3]  O. Klepper.  HEAT TRANSFER PERFORMANCE OF SHORT TWISTED TAPES. , 1972 .

[4]  Abhijit Date,et al.  Friction and heat transfer characteristics of flow through square duct with twisted tape insert , 2003 .

[5]  Paisarn Naphon,et al.  Heat transfer and pressure drop in the horizontal double pipes with and without twisted tape insert , 2006 .

[6]  R. M. Manglik,et al.  Heat Transfer and Pressure Drop Correlations for Twisted-Tape Inserts in Isothermal Tubes: Part I—Laminar Flows , 1993 .

[7]  J. P. D. Plessis,et al.  Friction factor prediction for fully developed laminar twisted-tape flow , 1984 .

[8]  J. P. D. Plessis,et al.  Heat transfer correlation for thermally developing laminar flow in a smooth tube with a twisted-tape insert , 1987 .

[9]  David B. Graves.  Plasma processing in microelectronics manufacturing , 1989 .

[10]  Anupam Dewan,et al.  Review of passive heat transfer augmentation techniques , 2004 .

[11]  Ventsislav D. Zimparov,et al.  Enhancement of heat transfer by a combination of a single-start spirally corrugated tubes with a twisted tape , 2002 .

[12]  S. F. Al-Fahed,et al.  Pressure drop and heat transfer comparison for both microfin tube and twisted-tape inserts in laminar flow , 1998 .

[13]  B. N. Prasad,et al.  Investigation of twisted tape inserted solar water heaters—heat transfer, friction factor and thermal performance results , 2000 .

[14]  Heat transfer and pressure drop for nitrogen flowing in tubes containing twisted tapes , 1969 .

[15]  R. M. Manglik,et al.  Heat Transfer and Pressure Drop Correlations for Twisted-Tape Inserts in Isothermal Tubes: Part II—Transition and Turbulent Flows , 1993 .

[16]  U. N. Gaitonde,et al.  Heat transfer and pressure drop characteristics of turbulent flow in a circular tube fitted with regularly spaced twisted-tape elements , 1990 .