THE ANALYTICAL DETERMINATION OF THE LOCAL HEAT TRANSFER CHARACTERISTICS OF GASES FLOWING TURBULENTLY IN THE THERMAL ENTRANCE REGION OF A CIRCULAR DUCT WITH LARGE TEMPERATURE DIFFERENCES BETWEENTHE GAS AND THE DUCT WALL
The mathematical description of flow with heat transfer is presented for a fluid flowing through a circular duct of constant area, under laminar and turbulent flow conditions. A review of the published literature is included that summarizes the analytical work pertinent to the calculation of heat transfer in the entrance region. A calculation of the neat transfer characteristics for air and carbon dioxide in the entrance region was made employing the boundary layer equations that were non-dimensionalized. The calculations were performed for the boundary conditions of constant heat flux (heating the gas), and constant wall temperature (cooling the gas); it was assumed that the velocity profile was fully developed and the temperature profile was uniform at the cross section where energy exchange was initiated. Local values of the Nusselt number and friction coefficient were calculated at nominal values of Reynolds number. The results indicate that the intensity of heating or cooling causes a much larger change in the local Nusselt number for air than for carbon dioxide, under similar conditions of flow at a given axial position. The calculated values of the friction coefficient in the presence of heat transfer did not vary appreciably with axial distance. Values of the thermal entrance length were computed as a function of the Reynolds number. Computed results are presented graphically and tabularly. (auth)
- Research Organization:
- Purdue Univ., Lafayette, Ind. Rocket Lab.; and Purdue Research Foundation, Lafayette, Ind.
- NSA Number:
- NSA-14-010576
- OSTI ID:
- 4181901
- Report Number(s):
- NP-8443; RM-57-2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Developing flow and heat transfer in a rectangular duct with a moving wall
Three dimensional laminar non-Newtonian fluid flow and heat transfer in the entrance region of a cross-shaped duct