Influence of Mach and Reynolds numbers on heat transfer to the leeward surface of a half-cone at hypersonic speed

1977 ◽  
Vol 11 (5) ◽  
pp. 736-739 ◽  
Author(s):  
M. M. Ardasheva ◽  
V. Ya. Borovoi ◽  
P. I. Gorenbukh ◽  
M. V. Ryzhkova
Keyword(s):  
Heat Transfer ◽  
Reynolds Numbers ◽  
Hypersonic Speed ◽  
Half Cone ◽  
Mach And Reynolds Numbers

The Application of Convective Cooling Enhancement of Span-Wise Cooling Holes in a Typical First Stage Turbine Blade

1991 ◽  
Author(s):  
D. J. Stankiewicz ◽  
T. R. Kirkham
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
Test Rig ◽  
Heated Oil ◽  
Cooling Enhancement ◽  
Mach And Reynolds Numbers

A technique of heat transfer enhancement is investigated whereby the internal span-wise cooling passages of a typical first stage gas turbine blade are modified by the introduction of circumferential ribs. The technique is verified by the use of a test rig incorporating a heated internally ribbed tube operating at the same range of Mach and Reynolds numbers as the turbine blade as well as by a test rig incorporating actual production blades immersed in a heated oil bath.

Blunt-Body Heat Transfer at Hypersonic Speed and Low Reynolds Numbers

1961 ◽  
Vol 28 (12) ◽  
pp. 962-971 ◽  
Author(s):  
ANTONIO FERRI ◽  
VICTOR ZAKKAY ◽  
LU TING
Keyword(s):  
Heat Transfer ◽  
Blunt Body ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Hypersonic Speed ◽  
Low Reynolds ◽  
Body Heat

On Blunt-Body Heat Transfer at Hypersonic Speed and Low Reynolds Numbers

1962 ◽  
Vol 29 (7) ◽  
pp. 882-883 ◽  
Author(s):  
Antonio Ferri ◽  
Victor Zakkay ◽  
Lu Ting
Keyword(s):  
Heat Transfer ◽  
Blunt Body ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Hypersonic Speed ◽  
Low Reynolds ◽  
Body Heat

The VKI Compression Tube Annular Cascade Facility CT3

1992 ◽  
Author(s):  
C. H. Sieverding ◽  
T. Arts
Keyword(s):  
Heat Transfer ◽  
Measurement Techniques ◽  
Reynolds Numbers ◽  
Operating Conditions ◽  
Wind Tunnels ◽  
Coolant Temperature ◽  
Real Size ◽  
Flow Quality ◽  
Annular Cascade ◽  
Mach And Reynolds Numbers

The purpose of this paper is to present the new transonic, annular facility developed at the von Karman Institute to investigate the aerodynamic heat transfer performances of real size advanced aero-engine and gas turbine components at correctly simulated operating conditions. The facility operates under the principle of an Isentropic Light Piston Compression Tube. Its definite advantage over classical blowdown wind tunnels is to independently model the freestream Mach and Reynolds numbers as well as the gas/wall/coolant temperature ratios. Its running time ranges between 0.1 and 1 s. The first part of the paper describes the design, the manufacturing and the installation of the different components of the wind tunnel and the test section. The second part deals with the different measurement techniques applied for aerodynamic and heat transfer measurements; it also describes some examples of the flow quality obtained in this new facility.

scholarly journals Experimental Determination of Stator Endwall Heat Transfer

1989 ◽  
Author(s):  
Robert J. Boyle ◽  
Louis M. Russell
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Test Section ◽  
Electrical Power ◽  
Exhaust System ◽  
Ambient Air ◽  
Reynolds Numbers ◽  
Inlet Velocity ◽  
Turbine Vane

Local Stanton numbers were experimentally determined for the endwall surface of a turbine vane passage. A six vane linear cascade having vanes with an axial chord of 13.81 cm was used. Results were obtained for Reynolds numbers based on inlet velocity and axial chord between 73,000 and 495,000. The test section was connected to a low pressure exhaust system. Ambient air was drawn into the test section, inlet velocity was controlled up to a maximum of 59.4 m/sec. The effect of the inlet boundary layer thickness on the endwall heat transfer was determined for a range of test section flow rates. The liquid crystal measurement technique was used to measure heat transfer. Endwall heat transfer was determined by applying electrical power to a foil heater attached to the cascade endwall. The temperature at which the liquid crystal exhibited a specific color was known from a calibration test. Lines showing this specific color were isotherms, and because of uniform heat generation they were also lines of nearly constant heat transfer. Endwall static pressures were measured, along with surveys of total pressure and flow angles at the inlet and exit of the cascade.

An Experimental and Numerical Study of Heat Transfer and Pressure Loss in a Rectangular Channel With V-Shaped Ribs

2006 ◽  
Author(s):  
Michael Maurer ◽  
Jens von Wolfersdorf ◽  
Michael Gritsch
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Thermal Performance ◽  
Pressure Loss ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
High Reynolds Numbers ◽  
High Reynolds

An experimental and numerical study was conducted to determine the thermal performance of V-shaped ribs in a rectangular channel with an aspect ratio of 2:1. Local heat transfer coefficients were measured using the steady state thermochromic liquid crystal technique. Periodic pressure losses were obtained with pressure taps along the smooth channel sidewall. Reynolds numbers from 95,000 to 500,000 were investigated with V-shaped ribs located on one side or on both sides of the test channel. The rib height-to-hydraulic diameter ratios (e/Dh) were 0.0625 and 0.02, and the rib pitch-to-height ratio (P/e) was 10. In addition, all test cases were investigated numerically. The commercial software FLUENT™ was used with a two-layer k-ε turbulence model. Numerically and experimentally obtained data were compared. It was determined that the heat transfer enhancement based on the heat transfer of a smooth wall levels off for Reynolds numbers over 200,000. The introduction of a second ribbed sidewall slightly increased the heat transfer enhancement whereas the pressure penalty was approximately doubled. Diminishing the rib height at high Reynolds numbers had the disadvantage of a slightly decreased heat transfer enhancement, but benefits in a significantly reduced pressure loss. At high Reynolds numbers small-scale ribs in a one-sided ribbed channel were shown to have the best thermal performance.

scholarly journals Parametric optimization of a stamped longitudinal vortex generator inside a circular tube of a solar water heater at low Reynolds numbers

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Felipe A. S. Silva ◽  
Luis Júnior ◽  
José Silva ◽  
Sandilya Kambampati ◽  
Leandro Salviano
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Reynolds Numbers ◽  
Geometric Parameters ◽  
Vortex Generators ◽  
Longitudinal Vortex ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water

AbstractSolar Water Heater (SWH) has low efficiency and the performance of this type of device needs to be improved to provide useful and ecological sources of energy. The passive techniques of augmentation heat transfer are an effective strategy to increase the convective heat transfer coefficient without external equipment. In this way, recent investigations have been done to study the potential applications of different inserts including wire coils, vortex generators, and twisted tapes for several solar thermal applications. However, few researchers have investigated inserts in SWH which is useful in many sectors where the working fluid operates at moderate temperatures. The longitudinal vortex generators (LVG) have been applied to promote heat transfer enhancement with a low/moderate pressure drop penalty. Therefore, the present work investigated optimal geometric parameters of LVG to enhance the heat transfer for a SWH at low Reynolds number and laminar flow, using a 3D periodical numerical simulation based on the Finite Volume Method coupled to the Genetic Algorithm optimization method (NSGA-II). The LVG was stamped over a flat plate inserted inside a smooth tube operating under a typical residential application corresponding to Reynolds numbers of 300, 600, and 900. The geometric parameters of LGV were submitted to the optimization procedure which can find traditional LVG such as rectangular-winglet and delta-winglet or a mix of them. The results showed that the application of LGVs to enhance heat transfer is an effective passive technique. The different optimal shapes of the LVG for all Reynolds numbers evaluated improved more than 50% of heat transfer. The highest augmentation heat transfer of 62% is found for the Reynolds number 900. However, the best thermo-hydraulic efficiency value is found for the Reynolds number of 600 in which the heat transfer intensification represents 55% of the pressure drop penalty.

Experimental and Analytical Investigation of Compact Liquid Cooled Heat Sinks

2004 ◽  
Author(s):  
M. Zugic ◽  
J. R. Culham ◽  
P. Teertstra ◽  
Y. Muzychka ◽  
K. Horne ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Tests ◽  
Reynolds Numbers ◽  
High Heat ◽  
Analytical Investigation ◽  
Boundary Resistance ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Air Cooling ◽  
Design Tools

Compact, liquid cooled heat sinks are used in applications where high heat fluxes and boundary resistance preclude the use of more traditional air cooling techniques. Four different liquid cooled heat sink designs, whose core geometry is formed by overlapped ribbed plates, are examined. The objective of this analysis is to develop models that can be used as design tools for the prediction of overall heat transfer and pressure drop of heat sinks. Models are validated for Reynolds numbers between 300 and 5000 using experimental tests. The agreement between the experiments and the models ranges from 2.35% to 15.3% RMS.

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