Impingement Cooling of Concave Surfaces With Lines of Circular Air Jets

1969 ◽  
Vol 91 (3) ◽  
pp. 149-155 ◽  
Author(s):  
D. E. Metzger ◽  
T. Yamashita ◽  
C. W. Jenkins
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Surface ◽  
Important Class ◽  
Two Dimensional ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Air Jets ◽  
Optimum Spacing ◽  
Circular Jets ◽  
Jet Nozzle

An experimental study of the heat transfer characteristics between single lines of circular jets and concave cylindrical surfaces is presented. It is intended to model a practically important class of impingement cooling configurations for which existing heat transfer correlations are not obviously applicable. The results clarify the present uncertain position with regard to the optimum spacing between the jet nozzle and the heat transfer surface and with regard to the center-to-center spacing between the jets. Some limited results for a two-dimensional jet impinging on the concave surfaces are also presented.

Heat Transfer Characteristics for Jet Array Impingement With Initial Crossflow

1983 ◽  
Author(s):  
L. W. Florschuetz ◽  
D. E. Metzger ◽  
C. C. Su
Keyword(s):  
Heat Transfer ◽  
Jet Flow ◽  
Heat Transfer Surface ◽  
Orifice Plate ◽  
Two Dimensional ◽  
Heat Transfer Characteristics ◽  
Adiabatic Wall ◽  
Air Jets ◽  
Nusselt Numbers ◽  
Turbine Airfoils

Two-dimensional arrays of circular air jets impinging on a heat transfer surface parallel to the jet orifice plate are considered. The jet flow, after impingement, is constrained to exit in a single direction along the channel formed by the jet orifice plate and the heat transfer surface. In addition to the crossflow which originates from the jets following impingement, an initial crossflow is present which approaches the array through an upstream extension of the channel. The temperature of the initial crossflow air may differ from the jet air temperature. The configurations considered are intended to model the impingement cooled midchord region of gas turbine airfoils in cases where an initial crossflow is also present. Nusselt numbers and dimensionless adiabatic wall temperatures resolved to one streamwise jet hole spacing were experimentally determined for ratios of the initial crossflow rate to the total jet flow rate ranging from zero to unity. These are presented and discussed relative to the flow and geometric parameters.

scholarly journals Time Averaged and Fluctuating Heat Transfer Measurements in an Atomising Mist Jet Nozzle

2009 ◽  
Author(s):  
Oisn F. P. Lyons ◽  
Darina B. Murray ◽  
Gerard Byrne ◽  
Tim Persoons
Keyword(s):  
Heat Transfer ◽  
Internal Structure ◽  
Research Group ◽  
Single Phase ◽  
Water Mist ◽  
Phase Behaviour ◽  
Heat Transfer Characteristics ◽  
Air Jets ◽  
Mist Flow ◽  
Jet Nozzle

Much is already known about the heat transfer characteristics of impinging air jets, and they are widely used in many engineering applications. There currently exist many correlations describing such characteristics. However, the complex internal structure of many nozzles can lead these to produce results which deviate from those predicted by correlations. One such nozzle is currently used in this research group to produce a water mist flow and this paper describes the experimental characteristics of its single phase behaviour.

Periodic Streamwise Variations of Heat Transfer Coefficients for Inline and Staggered Arrays of Circular Jets with Crossflow of Spent Air

1980 ◽  
Vol 102 (1) ◽  
pp. 132-137 ◽  
Author(s):  
L. W. Florschuetz ◽  
R. A. Berry ◽  
D. E. Metzger
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Transfer Surface ◽  
Test Surface ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Circular Jets ◽  
Impinging Flow

Heat transfer characteristics were measured for inline and staggered arrays of circular jets impinging on a surface parallel to the jet orifice plate. The impinging flow was constrained to exit in a single direction along the channel formed by the jet plate and the heat transfer surface. In this configuration the air discharged from upstream transverse rows of jet holes imposes a crossflow of increasing magnitude on the succeeding downstream jet rows. Streamwise heat transfer coefficient profiles were determined for a streamwise resolution of one-third the streamwise hole spacing, utilizing a specially constructed test surface. These profiles are characterized by significant periodic variations. The downstream amplitudes are diminished by the increasing crossflow magnitude, but can persist for at least ten rows of holes. Results were obtained for streamwise hole spacings of 5, 10, and 15 hole diameters; transverse hole spacings of 4, 6, and 8 diameters; and channel heights of 1, 2, and 3 diameters. The number of transverse hole rows was fixed at ten for all configurations. The characteristics of the periodic variations are presented and discussed as a function of the geometric parameters, including the effect of hole pattern.

Heat Transfer Characteristics of Impinging Two-Dimensional Air Jets

1966 ◽  
Vol 88 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Robert Gardon ◽  
J. Cahit Akfirat
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Two Dimensional ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Average Heat ◽  
Heat Transfer Coefficients ◽  
Transfer Characteristics ◽  
Air Jets

Local as well as average heat transfer coefficients between an isothermal flat plate and impinging two-dimensional jets were measured for both single jets and arrays of jets. For a large and technologically important range of variables the results have been correlated in relatively simple terms, and their application to design is briefly considered.

Heat Transfer Characteristics for Inline and Staggered Arrays of Circular Jets with Crossflow of Spent Air

1979 ◽  
Vol 101 (3) ◽  
pp. 526-531 ◽  
Author(s):  
D. E. Metzger ◽  
L. W. Florschuetz ◽  
D. I. Takeuchi ◽  
R. D. Behee ◽  
R. A. Berry
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Transfer Surface ◽  
Geometric Parameters ◽  
Channel Height ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Nusselt Numbers ◽  
Circular Jets ◽  
Impinging Flow

Heat transfer characteristics were measured for two-dimensional arrays of jets impinging on a surface parallel to the jet orifice plate. The impinging flow was constrained to exit in a single direction along the channel formed by the jet plate and the heat transfer surface. Both mean Nusselt numbers and streamwise Nusselt number profiles are presented as a function of Reynolds number and geometric parameters. The results show that significant periodic variations occur in the streamwise Nusselt number profiles, persisting downstream for at least ten rows of jet holes. Both channel height and hole spacing can have a significant effect on the streamwise profiles, smoothed across the periodic variations. Where significant differences exist, inline hole patterns provide better heat transfer than staggered ones, particularly downstream. These and other effects of the geometric parameters are presented and discussed.

Time Averaged and Fluctuating Heat Transfer Measurements in an Atomizing Mist Impinging Jet Nozzle

2010 ◽  
Author(s):  
Oisn Fergal Peter Lyons ◽  
Tim Persoons ◽  
Darina B. Murray
Keyword(s):  
Heat Transfer ◽  
Internal Structure ◽  
Research Group ◽  
Water Mist ◽  
Phase Behaviour ◽  
Heat Transfer Characteristics ◽  
Two Phase ◽  
Air Jets ◽  
Mist Flow ◽  
Jet Nozzle

Much is already known about the heat transfer characteristics of impinging air jets, and they are widely used in many engineering applications. There currently exist many correlations describing such characteristics. However, the complex internal structure of many nozzles can lead these to produce results which deviate from those predicted by correlations. One such nozzle is currently used in this research group to produce a water mist flow and this paper describes the experimental characteristics of its two phase behaviour.

Effects of Crossflow on Impingement Heat Transfer

1972 ◽  
Vol 94 (1) ◽  
pp. 35-41 ◽  
Author(s):  
D. E. Metzger ◽  
R. J. Korstad
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Important Class ◽  
Heat Transfer Characteristics ◽  
Transfer Rates ◽  
Opposite Wall ◽  
Transfer Characteristics ◽  
Air Jets ◽  
Impingement Heat Transfer ◽  
Air Stream

An experimental study of the effects of a cross-flowing air stream on the heat transfer characteristics of single lines of circular air jets impinging on plane surfaces is presented. The study models a practically important class of cooling configurations where jets issuing from one wall of a channel and impinging on the opposite wall are deflected by the exhausting flow of upstream jets. The upstream and downstream changes in heat transfer are evaluated separately and compared with heat transfer rates obtained in the absence of crossflow.

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