Experimental investigation of the inlet condition on jet impingement heat transfer using liquid crystal thermography

Ansu, U.; Godi, Sangamesh C.; Pattamatta, Arvind; Balaji, C.

doi:10.1016/j.expthermflusci.2016.08.028

Cited by 21 publications

(3 citation statements)

References 20 publications

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“…However, In the case of orifice nozzle, the heat transfer is somewhat less but they are the easiest to manufacture and consequently are commonly used. This observation correlates with the finding of Ansu et al (2016).…”

Section: Effect On Heat Transfersupporting

confidence: 92%

Numerical Simulation of Large Arrays of Impinging Jets on a Flat Surface

Chitsazan¹,

Klepp²,

Glasmacher³

2022

Front. Heat Mass Transf.

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The objective of the present research is the prediction of large arrays of impingement jets using a computational model. The heat transfer and the force coefficient from single and multiple jet rows (1, 2, 4, 8, and infinity rows) for two different nozzle shapes as either orifice or straight pipe on a fixed flat surface were numerically investigated for drying applications to understand the physical mechanisms which affect the uniformity of the local heat transfer and pressure force coefficient as well as average heat transfer coefficient. The pipe has always a higher averaged Nu and pressure force coefficient compared to the orifice nozzle. Increasing the nozzle to surface distance and decreasing the jet impingement angle reduces the heat transfer and pressure force coefficient. The local Nu number curves for multiple jet rows exhibited many different shapes because of different interference intensities between adjacent jets and also the magnitude of cross-flow. The impact of multiple jet rows on averaged Nu number and jet force coefficient was negligible compared to the single jet row.

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Section: Effect On Heat Transfersupporting

confidence: 92%

Numerical Simulation of Large Arrays of Impinging Jets on a Flat Surface

Chitsazan¹,

Klepp²,

Glasmacher³

2022

Front. Heat Mass Transf.

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“…An impinging jet is a common way to enhance heat and mass transfer in heating, cooling, and drying process [1,2]; it is encountered in many industrial processes such as gas turbine cooling, metal annealing, cooling the blades of aeroengines, and cooling electronic equipment [3,4]. In a freezer, this technology directs high-velocity air jets to break the insulating boundary layer that surrounds the products to be frozen, thereby enhancing the heat transfer and greatly reducing the freezing time to ensure food safety and quality [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Effect of Inclined Orifice in Air Impingement Freezer on Heat Transfer Characteristics of Steel Strip Surface

et al. 2023

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In order to improve the heat transfer characteristics of the air impingement freezer, an impingement freezer experimental table was designed as the research object in this paper. Numerical simulation technology was used to simulate the impingement freezer experimental table on the basis of test verification. When the other structural parameters in the impingement freezer experimental table were constant, the effect of the inclination angle of the orifice plate (θ = 60°, 65°, 70°, 75°, 80°, 85°, and 90°) on the heat transfer characteristics of a steel strip surface was analyzed by two aspects, the average Nusselt number and the heat transfer uniformity. The results showed that with the increase in the inclination angle of the orifice plate (60° ≤ θ ≤ 90°), the average Nusselt number of the steel strip surface was increased by 19.39%, and the heat transfer uniformity index was decreased by 33.69%. When θ = 90°, the average Nusselt number on steel strip was the maximum, which was 263.68, and the heat transfer uniformity index was the minimum, which was 0.2039. Therefore, the heat transfer intensity and heat transfer uniformity in the air impingement freezer could be improved when the inclination angle of the orifice plates was 90°. This helps to improve the output of the air impingement freezer, reduce energy consumption, and improve the quality of frozen food.

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“…They found that the round jet number required for the uniform cooling increased as the curvature ratio increased. Ansu et al [28] studied the inlet condition on the jet impingement heat transfer using liquid crystal thermography and developed correlations for the Nusselt number as a function of the Reynolds number and separation distance. A smaller separation distance and less crossflow resulted in a better heat transfer performance.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Heat Transfer on the Internal Surfaces of a Double-Wall Structure with Pin Fin Array

Zhang

Zhu

2020

Energies

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The double-wall structure is one of the most effective cooling techniques used in many engineering applications, such as turbine vane/blade, heat exchangers, etc. Heat transfer on the internal surfaces of a double-wall structure was studied at impinging Reynolds numbers ranging from 1 × 104 to 6 × 104 using the transient thermochromic liquid crystal (TLC) technique. The two-dimensional distributions of Nusselt numbers and their averaged values were obtained on the impingement surface, target surface and the pin fin surface. The Nusselt number correlations on the surfaces mentioned above were determined as a function of Reynolds number. The results show that the second peak values of the Nusselt number distribution appear on the target surface at all Reynolds numbers studied in this paper for a short distance of the target surface to impingement surface. This phenomenon becomes significant with the further increase of the Reynolds number. The difference between the Nusselt number at the second peak and the stagnation point decreases with the increasing Reynolds number. The maximal Nusselt number regions on the impingement surface appear at the left and right sides of the pin fins between the two impingement holes. The Nusselt numbers of the pin fin surfaces are highly dependent on their various locations in the double-wall structures. The contributions of the impingement surface, pin fin surface and target surface to the overall heat transfer rate are analyzed. The target surface contributed the largest amount of heat transfer rate with a value of about 62%. The heat transfer contribution is from 18% to 21% for the impingement surface and 16% to 18% for the pin fin surfaces within the studied Reynolds numbers.

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Experimental investigation of the inlet condition on jet impingement heat transfer using liquid crystal thermography

Cited by 21 publications

References 20 publications

Numerical Simulation of Large Arrays of Impinging Jets on a Flat Surface

Numerical Simulation of Large Arrays of Impinging Jets on a Flat Surface

Effect of Inclined Orifice in Air Impingement Freezer on Heat Transfer Characteristics of Steel Strip Surface

Experimental Study of Heat Transfer on the Internal Surfaces of a Double-Wall Structure with Pin Fin Array

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