Effect of Rarefied Atmosphere on Blunt Body Stagnation Region Flow and Heat Transfer

2016 ◽  
Author(s):  
Johnson C. Wang ◽  
Mary Vojtek ◽  
Charles Griffice
Keyword(s):  
Heat Transfer ◽  
Blunt Body ◽  
Stagnation Region ◽  
Flow And Heat Transfer ◽  
Region Flow

scholarly journals Heat Transfer and Fluid Dynamics Measurements in the Expansion Space of a Stirling Cycle Engine

2006 ◽  
Author(s):  
Nan Jiang ◽  
Terrence W. Simon
Keyword(s):  
Heat Transfer ◽  
High Efficiency ◽  
Stirling Engine ◽  
Transfer Coefficients ◽  
Head Region ◽  
Heat Transfer Coefficients ◽  
Flow And Heat Transfer ◽  
Engine Design ◽  
Region Flow ◽  
Design Calculations

The heater (or acceptor) of a Stirling engine, where most of the thermal energy is accepted into the engine by heat transfer, is the hottest part of the engine. Almost as hot is the adjacent expansion space of the engine. In the expansion space, the flow is oscillatory, impinging on a two-dimensional concavely-curved surface. Knowing the heat transfer on the inside surface of the engine head is critical to the engine design for efficiency and reliability. However, the flow in this region is not well understood and support is required to develop the CFD codes needed to design modern Stirling engines of high efficiency and power output. The present project is to experimentally investigate the flow and heat transfer in the heater head region. Flow fields and heat transfer coefficients are measured to characterize the oscillatory flow as well as to supply experimental validation for the CFD Stirling engine design codes. Presented also is a discussion of how these results might be used for heater head and acceptor region design calculations.

scholarly journals Radiative MHD Sutterby Nanofluid Flow Past a Moving Sheet: Scaling Group Analysis

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1430
Author(s):  
Mohammed M. Fayyadh ◽  
Kohilavani Naganthran ◽  
Md Faisal Md Basir ◽  
Ishak Hashim ◽  
Rozaini Roslan
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Numerical Solutions ◽  
Transfer Problem ◽  
Group Analysis ◽  
Shrinking Sheet ◽  
Nanofluid Flow ◽  
Stagnation Region ◽  
Flow And Heat Transfer ◽  
Scaling Group

The present theoretical work endeavors to solve the Sutterby nanofluid flow and heat transfer problem over a permeable moving sheet, together with the presence of thermal radiation and magnetohydrodynamics (MHD). The fluid flow and heat transfer features near the stagnation region are considered. A new form of similarity transformations is introduced through scaling group analysis to simplify the governing boundary layer equations, which then eases the computational process in the MATLAB bvp4c function. The variation in the values of the governing parameters yields two different numerical solutions. One of the solutions is stable and physically reliable, while the other solution is unstable and is associated with flow separation. An increased effect of the thermal radiation improves the rate of convective heat transfer past the permeable shrinking sheet.

Characteristics of Heat Transfer in Impinging Jets by Control of Vortex Pairing

1998 ◽  
Author(s):  
H. H. Cho ◽  
C. H. Lee ◽  
Y. S. Kim
Keyword(s):  
Heat Transfer ◽  
Flow Instability ◽  
Reynolds Numbers ◽  
Impinging Jets ◽  
Secondary Peak ◽  
Stagnation Region ◽  
Potential Core ◽  
Vortex Pairing ◽  
Flow And Heat Transfer ◽  
Impingement Surface

The present study is conducted experimentally to obtain heat transfer characteristics on the impingement surface for controlled jets. Counterflowing or coflowing stream around the jet periphery is used to control the jet at the nozzle lip. The characteristics of flow and heat transfer are studied on two different jet nozzle exit flow conditions, including a fully developed turbulent tube flow and an uniform velocity distribution flow. The experiments are carried out for nozzle-to-plate distances of 2 to 8 nozzle diameters, jet Reynolds numbers in the range of 10,000 to 70,000, and main and secondary flow velocity ratios, R = ΔU/2Ū, of 0.45 to 1.86. The secondary counter- and co-flows change the flow instability conditions in the shear layers resulting in changes of heat transfer on the impingement surface. For secondary counterflows, heat transfer on the impingement surface is changed little for the small nozzle-to-plate distance of H/D = 2, but is enhanced on the stagnation region with reduction on the secondary peak region for H/D = 4. Augmentation of heat transfer on the stagnation region increases with increasing jet Reynolds numbers. For secondary coflows, the jet potential core extends far downstream due to inhibited development of the vortices, but the heat transfer is reduced significantly and the secondary peak appears downstream with increasing blowing rates.

Stagnation-Point Heat Transfer: The Effect of the First Damko¨hler Similarity Parameter

1972 ◽  
Vol 94 (4) ◽  
pp. 410-414 ◽  
Author(s):  
A. Alkidas ◽  
P. Durbetaki
Keyword(s):  
Heat Transfer ◽  
Blunt Body ◽  
Combustible Mixture ◽  
Surface Heat ◽  
Arrhenius Law ◽  
Governing Equations ◽  
Similarity Parameter ◽  
Stagnation Region ◽  
Kinetics Of ◽  
Temperature Surface

The present study considers the heat interaction between a combustible mixture and a constant-temperature surface near the stagnation region of a blunt body. The steady-state governing equations have been solved numerically for the case of Le = 1. A second-order Arrhenius law is assumed to describe the chemical kinetics of the mixture. The first Damko¨hler similarity parameter is shown to critically influence the surface heat transfer. The parameter represents a measure of the convective time to the chemical time.

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