scholarly journals Discussion: “Heat Transfer by a Square Array of Round Air Jets Impinging Perpendicular to a Flat Surface Including the Effect of Spent Air” (Kercher, D. M., and Tabakoff, W., 1970, ASME J. Eng. Power, 92, pp. 73–82)

1970 ◽  
Vol 92 (1) ◽  
pp. 82-82
Author(s):  
D. E. Metzger
Keyword(s):  
Heat Transfer ◽  
Flat Surface ◽  
Air Jets ◽  
Square Array

Heat Transfer by a Square Array of Round Air Jets Impinging Perpendicular to a Flat Surface Including the Effect of Spent Air

1970 ◽  
Vol 92 (1) ◽  
pp. 73-82 ◽  
Author(s):  
D. M. Kercher ◽  
W. Tabakoff
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Perforated Plate ◽  
Graphical Form ◽  
Surface Distance ◽  
Air Jets ◽  
Degradation Factor ◽  
Spacing Parameter ◽  
Square Array ◽  
The Heat Transfer Coefficient

The results of an experimental investigation on the average surface heat transfer co-efficients under a perforated plate of multiple, square array, round impinging air jets are presented. Correlation of the heat transfer performance in a semi-enclosed environment is presented. The correlation includes the effects of the jet “spent air” flowing perpendicular to the jets; the effects of the jet diameter, jet spacing, and jet-to-surface distance. The data cover a range of jet diameter Reynolds number from 3 × 102 to 3 × 104, jet spacing from 3.1 to 12.5 dia, and plate-to-surface distance of 1.0 to 4.8 dia. The results are compared with previously reported investigations with reasonable agreement. Correlation is in the form NuD,x = φ1φ2ReDm(Zn/D)0.091Pr1/3 where φ1 and m are functions of the jet spacing parameter, Xn/D, and Reynolds number, and φ2 is the heat transfer coefficient degradation factor due to “spent air”. φ1, φ2 and m are presented in graphical form as a function of important dimensionless parameters.

Twin Pulsating Jets Impingement Heat Transfer for Fuel Preheating in Automotives

2014 ◽  
Vol 663 ◽  
pp. 322-328 ◽  
Author(s):  
Ali Ahmed Gitan ◽  
Rozli Zulkifli ◽  
Kamaruzaman Sopian ◽  
Shahrir Abdullah
Keyword(s):  
Heat Transfer ◽  
Ignition Process ◽  
Pulsation Frequency ◽  
Ir Camera ◽  
Copper Target ◽  
Air Jets ◽  
Air Jet ◽  
Impingement Heat Transfer ◽  
Pulsating Jet ◽  
Pulsating Jets

The problem of environmental pollution and depletion of fossil fuel can be reduced in automotives by using an alternative bio-fuel and improve the ignition process in engine. Both solutions need to use the fuel preheating technique. This work presents the idea of fuel preheating by using exhaust impingement on the fuel tank. Heat transfer between twin pulsating hot air jets and flat copper target was investigated as an application for preheating of automotive fuel to improve ignition process in the engine. The nozzle of 20 mm was used to produce air jet of Reynolds number, Re ≃ 5500 and a temperature of 54°C. The impinged target was imposed to still air surrounding at temperature of 24°C. Pulsating frequencies of 10-50 Hz were applied on air jets by using twin pulsating jet mechanism. The effect of pulsation frequency on heat transfer was measured using IR camera and heat flux-temperature micro foil sensor. The results obtained by both of these methods showed well agreement. Also, the results revealed significant influence of flow rate difference between steady and pulsating jet cases. In addition, the highest Nusselt number, Nu ≃ 7.2, was obtained at pulsation frequency of 20 Hz.

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.

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