Turbulent boundary layer heat transfer for a constant property particle-laden gas flow

The paper presents the results of experimental studies of heat transfer in a cylindrical tube, which is a simulation model of a fire tube. The experiments were performed on a gas-dynamic pipe of open type. The starting mode during operation of the gas turbine engine is one of the main modes in which failures sometimes occur. The failure may occur due to external heat transfer mode, when the thermal parameters of the gas flow exceed the calculated values and there takes place intense local heating of the streamlined surface of the structural element(s) of the engine. Experimental studies were carried out at different intensity of the increasing temperature of the working fluid, which allowed to fix the phenomenon of laminarization of the thermal turbulent boundary layer at the heat flow directed from the gas flow to the channel wall. In the event of laminarization phenomenon, the values of local heat transfer coefficients are reduced by 2.5-3 times. Since the discovery of this phenomenon, it has also been observed in various situations of accelerating the gas flow and even at high degrees of heating of the cylindrical pipe wall under stationary flow conditions. This phenomenon has been recorded for the first time in the non-stationary mode and the specified direction of the heat flow. The temperature head or temperature factor is proposed as a laminarization parameter of a turbulent boundary layer, and the boundary of the laminarization area of a turbulent boundary layer is Δ T ≥ 700 K.

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HEAT TRANSFER ACROSS THE CONSTANT PROPERTY TURBULENT BOUNDARY LAYER

Proceeding of International Heat Transfer Conference 8 ◽

10.1615/ihtc8.590 ◽

1986 ◽

Author(s):

James Sucec

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Turbulent Boundary Layer ◽

Constant Property

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A SEMI-EMPIRICAL DERIVATION OF FRICTION, HEAT-TRANSFER, AND MASS-TRANSFER COEFFICIENTS FOR THE CONSTANT PROPERTY TURBULENT BOUNDARY LAYER ON A FLAT PLATE

10.21236/ad0422359 ◽

1963 ◽

Author(s):

Neal Tetervin

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Mass Transfer ◽

Turbulent Boundary Layer ◽

Flat Plate ◽

Transfer Coefficients ◽

Constant Property ◽

Mass Transfer Coefficients ◽

Friction Heat ◽

Semi Empirical

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Laminar, Transition, and Turbulent Boundary-Layer Heat-Transfer Measurements With Wall Cooling in Turbulent Airflow Through a Tube

Journal of Heat Transfer ◽

10.1115/1.3580231 ◽

1969 ◽

Vol 91 (4) ◽

pp. 477-487 ◽

Cited By ~ 6

Author(s):

L. H. Back ◽

R. F. Cuffel ◽

P. F. Massier

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Turbulent Boundary Layer ◽

Flat Plate ◽

Reynolds Numbers ◽

Boundary Layer Transition ◽

Gas Temperature ◽

Layer Transition ◽

Constant Property ◽

Turbulent Airflow

Heat-transfer measurements were made along the wall in the thermal entrance region of a high-temperature turbulent airflow through a cooled tube 8.6 dia long. There was simultaneous development of the velocity and temperature profiles along the tube, the boundary-layer thickness at the inlet being small, compared to the tube radius. The measurements, made over a range of Reynolds numbers based on the tube diameter ReD from 7 × 104 to 106 and wall-to-gas temperature ratio Tw/Tt from 1/3 to 2/3, included natural boundary-layer transition data in the laminar, transition, and turbulent boundary-layer regions, and forced transition data obtained with a trip at the tube inlet. Although the inability to predict boundary-layer transition precludes a general correlation of the data, a fair correlation of the transitional data was obtained by accounting for the effective origin of the boundary layer. Transition Reynolds numbers, on the order of those found for flow over a flat plate, increased with ReD and decreased with wall cooling; i e., decreasing Tw/Tv In the turbulent boundary-layer region, both the natural transition data and tripped data were in general correspondence with the trend of a constant-property flat-plate prediction. However, the turbulent boundary-layer heat-transfer group with properties evaluated at the core flow temperature increased with wall cooling. Other investigations in the turbulent flow region are discussed in light of these measurements.

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