Laminarization of a Turbulent Boundary Layer in Nozzle Flow—Boundary Layer and Heat Transfer Measurements With Wall Cooling

1970 ◽  
Vol 92 (3) ◽  
pp. 333-344 ◽  
Author(s):  
L. H. Back ◽  
R. F. Cuffel ◽  
P. F. Massier
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Nozzle Flow ◽  
Conical Nozzle ◽  
Gas Temperature ◽  
Temperature Ratio ◽  
Half Angle ◽  
Flow Through ◽  
Complicated Nature

Boundary layer and heat transfer measurements are presented for flow through a cooled, conical nozzle with a convergent and divergent half-angle of 10 deg for a wall-to-total-gas temperature ratio of about 0.5. A reduction in heat transfer below values typical of a turbulent boundary layer was found when values of the parameter K = (μe/ρeue2) (due/dx) exceeded about 2 to 3 × 10−6. The boundary layer measurements, when viewed in conjunction with the heat transfer measurements, reveal the complicated nature of the flow and thermal behavior and their interrelationship when laminarization occurs.

Paradoxes of Heat Transfer on a Permeable Wall

2010 ◽  
Author(s):  
A. I. Leontiev ◽  
V. G. Lushchik ◽  
A. E. Yakubenko
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Numerical Modeling ◽  
Turbulent Boundary Layer ◽  
Prandtl Number ◽  
Wall Temperature ◽  
Gas Injection ◽  
Gas Mixtures ◽  
Permeable Wall ◽  
Gas Temperature

Numerical modeling of a turbulent boundary layer on a permeable wall with gas injection is performed. New effects are discovered. It is shown in particular that the wall temperature in the region of the gas film may be lower than the injected gas temperature. This effect is especially essential for gas mixtures with low values of the Prandtl number.

Effect of Uncooled Inlet Length and Nozzle Convergence Angle on the Turbulent Boundary Layer and Heat Transfer in Conical Nozzles Operating With Air

1967 ◽  
Vol 89 (4) ◽  
pp. 341-350 ◽  
Author(s):  
D. R. Boldman ◽  
J. F. Schmidt ◽  
R. C. Ehlers
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Theory ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Half Angle ◽  
Inlet Length ◽  
Pipe Inlet ◽  
Peak Value

Nozzle boundary layer and heat transfer measurements are presented for nozzles having half angles of convergence of 30 and 60 deg, each operating in conjunction with a short and long uncooled pipe inlet. The long inlet, which produced a fully developed turbulent boundary layer at the nozzle entrance, did not significantly alter the nozzle heat transfer distribution relative to values obtained with the short pipe inlet. Peak heat transfer coefficients for the high convergence nozzle were nearly 40 percent higher than the peak value for the 30 deg half angle of convergence nozzle. Measured heat transfer coefficients were compared to predictions based on a boundary layer theory and a pipe flow type correlation.

Turbulent Boundary Layer and Heat Transfer Measurements Along a Convergent-Divergent Nozzle

1971 ◽  
Vol 93 (4) ◽  
pp. 397-407 ◽  
Author(s):  
L. H. Back ◽  
R. F. Cuffel
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Reynolds Number ◽  
Friction Coefficient ◽  
Energy Equation ◽  
Integral Form ◽  
Conical Nozzle ◽  
Half Angle ◽  
Semi Empirical ◽  
The Relationship

Boundary layer and heat transfer measurements are presented along a cooled, conical nozzle with a convergent and a divergent half-angle of 10 deg. Semi-empirical analyses are considered in conjunction with the measurements. The heat transfer is found to be describable by using the integral form of the energy equation once the relationship between the Stanton number and energy thickness Reynolds number has been established from the measurements. The friction coefficient, however, is not described accurately along the entire nozzle by existing formulations considered.

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

1969 ◽  
Vol 91 (4) ◽  
pp. 477-487 ◽  
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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