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Dongsheng Wen - One of the best experts on this subject based on the ideXlab platform.
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jet impingement heat transfer on a Concave Surface in a wing leading edge experimental study and correlation development
Experimental Thermal and Fluid Science, 2016Co-Authors: Long Peng, Guiping Lin, Lizhan Bai, Dongsheng WenAbstract:Extensive experimental studies of the heat transfer characteristics of jet impingement on a variable-curvature Concave Surface in a wing leading edge were conducted for aircraft anti-icing applications. The experiments were performed using a piccolo tube with three rows of aligned jet holes over a wide range of parameters: the jet Reynolds number (Rej) from 50,000 to 90,000, the relative tube-to-Surface distance (H/d) from 1.74 to 20.0, the jet impingement angle (α) from 66° to 90°, and the relative chordwise arc length in the jet impingement zone (r/d) from 13.2 to 34.8. Experimental results indicated that the heat transfer performance at the stagnation point was enhanced with increasing Rej and α, and an optimal H/d existed to achieve the best heat transfer performance at the stagnation point corresponding to specific operating parameters. It was found that the attenuation coefficient curve of jet impingement heat transfer in the chordwise direction exhibited an approximate bell shape with the peak located at the stagnation point, affected only by r/d in the peak zone. In the non-peak zone, however it was affected significantly by a variety of factors including Rej, H/d and r/d. Experimental data-based correlations of the Nusselt number at the stagnation point and the distribution of the attenuation coefficient in the chordwise direction were developed and validated, which contributes significantly to the future design of a wing anti-icing system with three rows of aligned jet holes.
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experimental study of jet impingement heat transfer on a variable curvature Concave Surface in a wing leading edge
International Journal of Heat and Mass Transfer, 2015Co-Authors: Long Peng, Guiping Lin, Lizhan Bai, Dongsheng WenAbstract:In this paper, extensive experimental investigation of the heat transfer characteristics of jet impingement on a variable-curvature Concave Surface in a wing leading edge was conducted for aircraft anti-icing applications. The experiments were carried out over a wide range of parameters: the jet Reynolds number, Rej, from 51,021 to 85,340, the relative tube-to-Surface distance, H/d, from 1.736 to 19.76, and the circumferential angle of jet holes on the piccolo tube, θ, from −60° to 60°. In addition, jet impingements with single one, two and three rows of aligned jet holes were all investigated. Experimental results revealed the effects of various parameters on the performance and characteristics of jet impingement heat transfer in the specific structure adopted here, and our insufficient understanding on the corresponding physical mechanism was presented. It was found that the jet impingement heat transfer performance was enhanced with the increase of jet Reynolds number. For single one row of jet holes, an optimal H/d of 4.5 was determined under Rej = 51,021 and d = 2 mm, for which the jet impingement achieved the best heat transfer performance. For two and three rows of aligned jet holes, the Nux curves in the chordwise direction exhibited much different shapes due to different intensity of the interference between adjacent air jets. This work contributes to a better understanding of the jet impingement heat transfer on a Concave Surface in a wing leading edge, which can lead to optimal design of the aircraft anti-icing system.
Lizhan Bai - One of the best experts on this subject based on the ideXlab platform.
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jet impingement heat transfer on a Concave Surface in a wing leading edge experimental study and correlation development
Experimental Thermal and Fluid Science, 2016Co-Authors: Long Peng, Guiping Lin, Lizhan Bai, Dongsheng WenAbstract:Extensive experimental studies of the heat transfer characteristics of jet impingement on a variable-curvature Concave Surface in a wing leading edge were conducted for aircraft anti-icing applications. The experiments were performed using a piccolo tube with three rows of aligned jet holes over a wide range of parameters: the jet Reynolds number (Rej) from 50,000 to 90,000, the relative tube-to-Surface distance (H/d) from 1.74 to 20.0, the jet impingement angle (α) from 66° to 90°, and the relative chordwise arc length in the jet impingement zone (r/d) from 13.2 to 34.8. Experimental results indicated that the heat transfer performance at the stagnation point was enhanced with increasing Rej and α, and an optimal H/d existed to achieve the best heat transfer performance at the stagnation point corresponding to specific operating parameters. It was found that the attenuation coefficient curve of jet impingement heat transfer in the chordwise direction exhibited an approximate bell shape with the peak located at the stagnation point, affected only by r/d in the peak zone. In the non-peak zone, however it was affected significantly by a variety of factors including Rej, H/d and r/d. Experimental data-based correlations of the Nusselt number at the stagnation point and the distribution of the attenuation coefficient in the chordwise direction were developed and validated, which contributes significantly to the future design of a wing anti-icing system with three rows of aligned jet holes.
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experimental study of jet impingement heat transfer on a variable curvature Concave Surface in a wing leading edge
International Journal of Heat and Mass Transfer, 2015Co-Authors: Long Peng, Guiping Lin, Lizhan Bai, Dongsheng WenAbstract:In this paper, extensive experimental investigation of the heat transfer characteristics of jet impingement on a variable-curvature Concave Surface in a wing leading edge was conducted for aircraft anti-icing applications. The experiments were carried out over a wide range of parameters: the jet Reynolds number, Rej, from 51,021 to 85,340, the relative tube-to-Surface distance, H/d, from 1.736 to 19.76, and the circumferential angle of jet holes on the piccolo tube, θ, from −60° to 60°. In addition, jet impingements with single one, two and three rows of aligned jet holes were all investigated. Experimental results revealed the effects of various parameters on the performance and characteristics of jet impingement heat transfer in the specific structure adopted here, and our insufficient understanding on the corresponding physical mechanism was presented. It was found that the jet impingement heat transfer performance was enhanced with the increase of jet Reynolds number. For single one row of jet holes, an optimal H/d of 4.5 was determined under Rej = 51,021 and d = 2 mm, for which the jet impingement achieved the best heat transfer performance. For two and three rows of aligned jet holes, the Nux curves in the chordwise direction exhibited much different shapes due to different intensity of the interference between adjacent air jets. This work contributes to a better understanding of the jet impingement heat transfer on a Concave Surface in a wing leading edge, which can lead to optimal design of the aircraft anti-icing system.
Long Peng - One of the best experts on this subject based on the ideXlab platform.
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jet impingement heat transfer on a Concave Surface in a wing leading edge experimental study and correlation development
Experimental Thermal and Fluid Science, 2016Co-Authors: Long Peng, Guiping Lin, Lizhan Bai, Dongsheng WenAbstract:Extensive experimental studies of the heat transfer characteristics of jet impingement on a variable-curvature Concave Surface in a wing leading edge were conducted for aircraft anti-icing applications. The experiments were performed using a piccolo tube with three rows of aligned jet holes over a wide range of parameters: the jet Reynolds number (Rej) from 50,000 to 90,000, the relative tube-to-Surface distance (H/d) from 1.74 to 20.0, the jet impingement angle (α) from 66° to 90°, and the relative chordwise arc length in the jet impingement zone (r/d) from 13.2 to 34.8. Experimental results indicated that the heat transfer performance at the stagnation point was enhanced with increasing Rej and α, and an optimal H/d existed to achieve the best heat transfer performance at the stagnation point corresponding to specific operating parameters. It was found that the attenuation coefficient curve of jet impingement heat transfer in the chordwise direction exhibited an approximate bell shape with the peak located at the stagnation point, affected only by r/d in the peak zone. In the non-peak zone, however it was affected significantly by a variety of factors including Rej, H/d and r/d. Experimental data-based correlations of the Nusselt number at the stagnation point and the distribution of the attenuation coefficient in the chordwise direction were developed and validated, which contributes significantly to the future design of a wing anti-icing system with three rows of aligned jet holes.
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experimental study of jet impingement heat transfer on a variable curvature Concave Surface in a wing leading edge
International Journal of Heat and Mass Transfer, 2015Co-Authors: Long Peng, Guiping Lin, Lizhan Bai, Dongsheng WenAbstract:In this paper, extensive experimental investigation of the heat transfer characteristics of jet impingement on a variable-curvature Concave Surface in a wing leading edge was conducted for aircraft anti-icing applications. The experiments were carried out over a wide range of parameters: the jet Reynolds number, Rej, from 51,021 to 85,340, the relative tube-to-Surface distance, H/d, from 1.736 to 19.76, and the circumferential angle of jet holes on the piccolo tube, θ, from −60° to 60°. In addition, jet impingements with single one, two and three rows of aligned jet holes were all investigated. Experimental results revealed the effects of various parameters on the performance and characteristics of jet impingement heat transfer in the specific structure adopted here, and our insufficient understanding on the corresponding physical mechanism was presented. It was found that the jet impingement heat transfer performance was enhanced with the increase of jet Reynolds number. For single one row of jet holes, an optimal H/d of 4.5 was determined under Rej = 51,021 and d = 2 mm, for which the jet impingement achieved the best heat transfer performance. For two and three rows of aligned jet holes, the Nux curves in the chordwise direction exhibited much different shapes due to different intensity of the interference between adjacent air jets. This work contributes to a better understanding of the jet impingement heat transfer on a Concave Surface in a wing leading edge, which can lead to optimal design of the aircraft anti-icing system.
Hadi Ahmadi - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation of semi confined turbulent slot jet impingement on a Concave Surface using an al2o3 water nanofluid
Applied Mathematical Modelling, 2016Co-Authors: Hadi Ahmadi, Kazem Esmailpour, Mokhtari R Moghari, Arun S. MujumdarAbstract:Abstract This paper presents and discusses results of a computational study of the flow field and heat transfer characteristics for a turbulent slot jet of an Al2O3–water nanofluid impinging normally on to a semi-circular Concave Surface. A wide range of various flow and geometrical parameters, including the nanoparticle volume fraction (Φ), jet Reynolds number (Re), and jet-to-target distance (h/B) have been considered. The results are presented in terms of the streamline patterns, local and average Nusselt numbers, stagnation Nusselt number, shear stress distribution, and pumping power. The results show a significant improvement of heat transfer rate due to the presence of the nanoparticles in water. Moreover, for ratios of h/B greater than three, the maximum average heat transfer rate from the Concave Surface occurs at h/B = 5. An increase in the jet Reynolds number and nanoparticle concentration leads to an improved cooling performance of jet impingement on the Concave Surface. However, the elevated viscosity of the nanofluid has the adverse effect of increasing the pumping power needed per unit of heat transferred.
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Numerical investigation of semi-confined turbulent slot jet impingement on a Concave Surface using an Al2O3–water nanofluid
Applied Mathematical Modelling, 2016Co-Authors: Hadi Ahmadi, R. Mokhtari Moghari, Kazem Esmailpour, Arun S. MujumdarAbstract:Abstract This paper presents and discusses results of a computational study of the flow field and heat transfer characteristics for a turbulent slot jet of an Al2O3–water nanofluid impinging normally on to a semi-circular Concave Surface. A wide range of various flow and geometrical parameters, including the nanoparticle volume fraction (Φ), jet Reynolds number (Re), and jet-to-target distance (h/B) have been considered. The results are presented in terms of the streamline patterns, local and average Nusselt numbers, stagnation Nusselt number, shear stress distribution, and pumping power. The results show a significant improvement of heat transfer rate due to the presence of the nanoparticles in water. Moreover, for ratios of h/B greater than three, the maximum average heat transfer rate from the Concave Surface occurs at h/B = 5. An increase in the jet Reynolds number and nanoparticle concentration leads to an improved cooling performance of jet impingement on the Concave Surface. However, the elevated viscosity of the nanofluid has the adverse effect of increasing the pumping power needed per unit of heat transferred.
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effect of intermittent and sinusoidal pulsed flows on impingement heat transfer from a Concave Surface
International Journal of Thermal Sciences, 2014Co-Authors: Javad Mohammadpour, Arun S. Mujumdar, Mehran Rajabizargarabadi, Hadi AhmadiAbstract:Abstract The effects of square waveform (intermittent) and sinusoidal waveform pulsation are investigated on the heat transfer rate from a slot jet impinging to a Concave Surface. In this respect, a numerical analysis of turbulent flow and heat transfer in a two-dimensional jet is performed using the RNG k–ɛ model. The effects of jet Reynolds number, pulsation frequency, nozzle to target Surface spacing in both types of waves and the effect of the amplitude of sinusoidal waves on distribution of the Surface time-averaged local Nusselt number are studied. Results show that in the pulsed jets, the increase of frequency in the range of 20–80 Hz and the Reynolds number in the range of 4740–7200 cause the increase of the time-averaged Nusselt number compared to steady jet cases. In the pulsed jets, reducing the nozzle-to-Surface distance causes the increase of heat transfer from the target Surface. Moreover, the increase of pulse amplitude from 0.2 to 1.0 in the sinusoidal waves increases the time-averaged Nusselt number. Finally, the comparison of results indicates a considerable increase of the heat transfer rate for the square form waves than sinusoidal waves compared to the steady state data.
Mansoo Choi - One of the best experts on this subject based on the ideXlab platform.
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Measurements of impinging jet flow and heat transfer on a semi-circular Concave Surface
International Journal of Heat and Mass Transfer, 2000Co-Authors: Mansoo Choi, Han Seoung Yoo, Geunyoung Yang, Joon Sik Lee, Dong Kee SohnAbstract:Abstract An experimental study of fluid flow and heat transfer has been carried out for jet impingement cooling on a semi-circular Concave Surface. The distributions of mean velocity and velocity fluctuation on the Concave Surface have been measured in free, impinging and wall jet flow regions by using a Laser Doppler Anemometer. Local Nusselt numbers have also been measured. Variations of jet Reynolds numbers, the spacing between the nozzle and the target and the distance from the stagnation point in the circumferential direction have been considered. Emphasis has been placed on measuring turbulent jet flow characteristics including impinging and evolving wall jets and interpreting heat transfer data, particularly, the occurrence and its location of secondary peak in connection with data of measured mean velocity and velocity fluctuations on the Concave Surface.
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an experimental study of slot jet impingement cooling on Concave Surface effects of nozzle configuration and curvature
International Journal of Heat and Mass Transfer, 1999Co-Authors: Geunyoung Yang, Mansoo ChoiAbstract:Abstract An experimental study has been carried out for jet impingement cooling on a semi-circular Concave Surface when jet flows were ejected from three different slot nozzles—round shaped nozzle, rectangular shaped nozzle and 2D contoured nozzle. Experiments have been conducted with variations of nozzle exit Reynolds number (Re2B) in the range of 5920 ⩽ Re2B ⩽ 25500 and nozzle-to-Surface distance (zn) in the range of 1/2 ⩽ zn/B ⩽ 20 to determine the heat transfer coefficients under a constant heat flux condition. The developing structures of free jets were measured by hot-wire anemometer to understand the characteristics of heat transfer in conjunction with measured jet flows. Markedly different flow and heat transfer characteristics have been observed depending on different nozzle shapes. Average heat transfer rates for impingement on the Concave Surface are found to be more enhanced than the flat plate results due to the effect of curvature. Comparisons between the present results and the existing experimental results have also been made.
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A study of jet impingement cooling on the semi-circular Concave Surface: Effects of two different nozzle configurations
1995Co-Authors: Geunyoung Yang, Mansoo Choi, Joon Sik LeeAbstract:An experimental study has been carried out for jet impingement cooling on the semi-circular Concave Surface. Two different two-dimensional slot nozzles (round shaped nozzle and rectangular shaped nozzle) have been used and heat transfer coefficients on the Concave Surface have been measured under a constant heat flux condition. The characteristics of heat transfer have been discussed in conjunction with measured jet flows. Velocity and absolute magnitude of the velocity fluctuations of free jets issuing from two different nozzles have been measured by Laser Doppler Anemometry. The effects of the nozzle shape, the spacing between the nozzle exit and the stagnation point of the Surface and the nozzle exit Reynolds number on heat transfer were determined.