Turbulent heat transfer internal flow

JACKSON, J.D. and LI, J., Buoyancy-influenced variable property turbulent heat transfer to air flowing in a uniformly heated vertical tube , (Proc. 2 EF International Conference on Turbulent Heat Transfer, Manchester), Vol. 1, 2.31-2.49, June (1998). 

GASFLOW models geometrically complex containments, buildings, and ventilation systems with multiple compartments and internal structures. It calculates gas and aerosol behavior of low-speed buoyancy driven flows, diffusion-dominated flows, and turbulent flows dunng deflagrations. It models condensation in the bulk fluid regions heat transfer to wall and internal stmetures by convection, radiation, and condensation chemical kinetics of combustion of hydrogen or hydrocarbon.s fluid turbulence and the transport, deposition, and entrainment of discrete particles. 

Withers, J. G., Tube-Side Heat Transfer and Pressure Drop for Tubes Having Helical Internal Ridging and Turbulent/Tran-sitional Flow of Single-Phase Fluid Part 1 and Part 2 Single Helix Ridging, Heat Trans. Eng, V. 2, Jufy-Sept., Oct.-Dec. (1980) p. 49. 

Operated in this manner, the shell-and-tube type is a flooded evaporator (see Figure 7.3) and has oil drainage pots if using ammonia, or a mixture bleed system if the refrigerant is one of the halocarbons. The speed of the liquid within the tubes should be about 1 m/ s or more, to promote internal turbulence for good heat transfer. End cover baffles will constrain the flow to a number of passes, as with the shell-and-tube condenser. (See Section 6.4.)... 

Derive an expression relating the pressure drop for the turbulent flow of a fluid in a pipe to the heat transfer coefficient at the walls on the basis of the simple Reynolds analogy. Indicate the assumptions which are made and the conditions under which you would expect it to apply closely. Air at 320 K and atmospheric pressure is flowing through a smooth pipe of 50 mm internal diameter, and the pressure drop over a 4 m length is found to be 150 mm water gauge. By how much would you expect the air temperature to fall over the first metre if the. wall temperature there is 290 K ... 

Cooper, D., D. C. Jackson, and B. E. Launder (1993a). Impinging jet studies for turbulence model assessment - I. Flow-field experiments. International Journal of Heat and Mass Transfer 36, 2675-2684. 

Aldredge, R. G. 1996. A novel flow reactor for the study of heat-loss effects on turbulent flame propagation. International Communications Heat Mass Transfer 22 1173-79. 

Internal flows of the type here being considered occur in heat exchangers, for example, where the fluid may flow through pipes or between closely spaced plates that effectively form a duct Although laminar duct flows do not occur as extensively as turbulent duct flows, they do occur in a number of important situations in which the size of the duct involved is small or in which the fluid involved has a relatively high viscosity. For example, in an oil cooler the flow is usually laminar. Conventionally, it is usual to assume that a higher heat transfer rate is achieved with turbulent flow than with laminar flow. However, when the restraints on possible solutions to a particular problem are carefully considered, it often turns out that a design that involves laminar flow is the most efficient from a heat transfer viewpoint. 

This chapter has been concerned with flows in wb ch the buoyancy forces that arise due to the temperature difference have an influence on the flow and heat transfer values despite the presence of a forced velocity. In extemai flows it was shown that the deviation of the heat transfer rate from that which would exist in purely forced convection was dependent on the ratio of the Grashof number to the square of the Reynolds number. It was also shown that in such flows the Nusselt number can often be expressed in terms of the Nusselt numbers that would exist under the same conditions in purely forced and purely free convective flows. It was also shown that in turbulent flows, the buoyancy forces can affect the turbulence structure as well as the momentum balance and that in turbulent flows the heat transfer rate can be decreased by the buoyancy forces in assisting flows whereas in laminar flows the buoyancy forces essentially always increase the heat transfer rate in assisting flow. Some consideration was also given to the effect of buoyancy forces on internal flows. 

Equipment designs based on indirect conduction usually transfer the heat from the primary heat transfer fluid to the intermediate wall within some kind of internal duct or channel. Transfer coefficients for these cases depend on the nature of the flow (laminar or turbulent) and the geometry of the duct or channel (short or long). Expressions for evaluating the transfer coefficients for these cases are available in standard texts. An expression for the convective thermal resistance can be generated similar to that derived for the conductive resistance ... 

T. Wang, Z.Y. Luo, C.H. Shou, S.B. Zhang and K.F. Cen (2007). Experimental study on convection heat transfer of nanocolloidal dispersion in a turbulent flow, in Proceedings of the International Conference on Power Engineering 2007, 993-998 (2007). 

T. C. Camavos, Heat Transfer Performance of Internally Finned Tubes in Turbulent Flow, in Advances in Enhanced Heat Transfer, pp. 61-67, ASME, New York, 1979. 

S. V. Patankar, M. Ivanovic, and E. M. Sparrow, Analysis of Turbulent Flow and Heat Transfer in Internally Finned Tube and Annuli, J. Heat Transfer (101) 29-37,1979. 

T. C. Carnavos, Cooling Air in Turbulent Flow With Internally Finned Tubes, Heat Transfer Eng. (1/2) 4W6,1979. 

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