INVESTIGATION OF TWISTED TAPE TURBULATOR FOR FIRE TUBE BOILER Part I. Heat Transfer
محتوى المقالة الرئيسي
الملخص
The present work presents a new experimental study of the enhancement of turbulent
convection heat transfer inside tubes for combined thermal and hydrodynamic entry length of one
popular “turbulator” (twisted tape with width slightly less than internal tube diameter) inserted for
fire tube boilers. Cylindrical combustion chamber was used to burn (1.6 to 7kg/h) fuel oil #2 to
deliver hot gases with ranges of Reynolds number (10500 to 21700), and (11400 to 24150) for both
empty and inserted tube respectively.A uniform wall temperature technique was used by keeping
approximately constant water temperature difference (25ºC) between inlet and exit cooling water in
parallel flow shell and tube heat exchanger. The test tube consisted of smooth carbon steel tube of
(2400mm) long and (52mm) internal diameter. This test tube instrumented to derive local heat
transfer coefficient and local flue gasses static pressure.The experimental results show that for the
same fuel consumption, twisted tape insert with (H/D = 11.15) enhanced the mean Nusselt number
in (75.2%), (68.8%), (49.8%), (40.3%), and (16.7%) for fuel consumption (7kg/h), (6.16kg/h),
(4.5kg/h), (3.24kg/h), and (1.6kg/h) respectively.A set of empirical correlations that permit the
evaluation of the mean Nusselt number (for developing and fully developed region), and average
Nusselt number (for developed region) for empty and inserted tube are generated for engineering
applications.
تفاصيل المقالة
كيفية الاقتباس
تواريخ المنشور
المراجع
Advanced Boiler Technology Group, 2002. ”Advanced fire-tube boiler project”.
Ayhan, B. and Demirtas. 2001. “Investigation of turbulators for fire-tube boilers using exergy analysis”. Turk J. Engin. Environ Sci.pp.249-258.
British Standard, European Standard ISO 5167-1. 2003. “Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full”- Part 1 : General principles and requirements .
British Standard, European Standard ISO 5167-2.2003. “Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full” - Part 2. British Standard, 2790. 1989. ”British
standard specification for design and manufacture of shell boiler of welded construction”. Chattopadhyay, P. 1998. “Boiler Operation Engineering”. Tata Mc Graw – Hill, New Delhi.
Gnielinski, V. 1976. “New equations for heat and mass transfer in turbulent pipe and channel flow”. International Chemical Engineering. Vol. 16, No. 2, pp. 359-368.
Insayif, R. K. 2008. “An investigation of thermal behavior of fire tube boiler utilizing unconventional tubes”. M.Sc. thesis, College of Engineering, Baghdad University.
Junkhan, G.H. ; Bergles, A.E. ; Nirmalan, V.; and Ravigururajan, T. 1985.“Investigation of turbulators for fire-tube boilers”.Journal of Heat Transfer, Vol. 107, pp. 354-360.
Junkhan, G.H. ; Bergles, A.E. ; Nirmalan, V.; and Hanno, W. (1988).“Performance evaluation of the effects of a group of
turbulater in inserts on heat transfer from gases in tubes”. ASHRAE Transactions. pp. 1195-1212.
Kays, W.M. and Crawford, M.E. 1980.“Convective heat and mass transfer ”. McGraw- Hill, New York.
Kays, W.M. and London, A.L. 1964. “Compact heat exchangers”, McGraw- Hill, New York.
Kays, W.M. and Perkins, H. C. 1973. “Forced convection ,internal flow in ducts”. In “ Handbook of heat transfer”,
Rohsenow,W. M. and Hartnett,J. P. (eds.). McGraw- Hill, New York.
Klaczak, A. 1973. “Heat transfer in tube with spiral and helical turbulators”. Journal of Heat Transfer, pp. 557-559.
Kline, S. J. 1985. “The purposes of uncertainty analysis”. Journal of Fluids Engineering. Vol. 107, pp. 153-160.
McAdams, W.H. 1954. “Heat transmission”. McGraw- Hill, New York.
Moffat, R. J. 1985. “Using uncertainty analysis in the planning of an experiment”. Journal of Fluids Engineering. Vol. 107, pp. 173-178.
Neshumayev, D.; Ots, A. ; Laid, J.; and Tiikma, T. 2004. “Experimental investigation of various turbulator inserts in gas-heated channels”. Experimental Thermal and Fluid Science, vol. 28, pp. 877-886.
Nirmalan, V.; Junkhan, G.H. ; and Bergles, A.E. (1986a). “Investigation of the effect of turbulence –producing insrts on heat
transfer in tubes with application to fire- tube boilers”. ASHRAE Transaction, Vol. 92, part 1B, pp. 791-809.
Nirmalan,V. ; Junkhan, G.H. ; and Bergles, A.E. (1986b). “Mechanisms of enhancement with turbulators for fire-tube boilers”. ASHRAE Transactions ,Vol. 92, part 2B, pp. 496-505.
Riello S.p.A. 2001. “Forced Draught Burner handbook”. Legnago – Italy.
Standards of the tubular exchanger manufacturers association (TEMA). 1988.
Seventh edition. New York. The American Society of Mechanical Engineers. 1989. (ASME) boiler and pressure
vessel code. Section I, Power boilers. NewYork.