Influence of the nozzle shape on heat transfer uniformity for in-line array of impinging air jets

Attalla, M.; Maghrabie, Hussein M.; Qayyum, Abdul; Al-Hasnawi, Adnan Ghareeb Tuaamah; Specht, Eckehard

doi:10.1016/j.applthermaleng.2017.03.134

Cited by 36 publications

(4 citation statements)

References 30 publications

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“…Their conclusions were in line with the findings of Lytle and Webb [16]and Gao [17]. For both square and round jets, Attallaet al [18] provides empirical correlations to calculate heat transfer uniformity and average Nusselt numbers.They looked at how the geometry of the nozzle affected the heat transfer uniformity when jets impinged perpendiculary on a flat plate. Stagnation Nusselt number correlation was published by Persoons et al [19],taking into account the effects of all pertinent scaling parameters, including the Reynolds number (from 500 to 1500),stroke length (from 2 to 40) and jet surface distance (from 2 to 16).…”

Section: Introductionsupporting

confidence: 75%

Artificial neural networks application on average and stagnation Nusselt number prediction for impingement cooling of flat plate with helically coiled air jet

Fawaz,

Osama,

Maghrabie

2023

Preprint

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Graphical Abstract Abstract In order to estimate the average and stagnation Nusselt numbers for turbulent flow for impingement cooling of a flat plate with a helically coiled air jet, a new artificial neural network (ANN) model is presented in the present study. A new dataset of stagnation and average Nusselt numbers as a function of Reynolds number (Re) varied from 5000 to 30000, nozzle plate spacing ratio changed from 2 to 8, and jet helical angle varied from 0 to 60 degrees was created based on an experimental investigation. The ANN structure composed of three layers with hidden neurons of 14-10-8. The training process comprises feed-forward propagation of the selected input parameters, back-propagation with biases and weight adjustments, and loss function evaluation for the training and validation datasets. The activation function of the output layer is a linear function, and the rectified linear unit activation function is utilized in the hidden layers. The adaptive moment estimation algorithm(ADAM) is employed to minimize the loss function to accelerate the ANN training. To prevent an increase in training time caused by the marked discrepancy in the gradients of loss function considering the values of the weights, the “MinMax” normalization strategy was used. For the ANN model, the mean absolute percent error values were 2.35% for the average Nusselt number and 2.52% for the stagnation Nusselt number. As a result, greater accuracy was obtained as compared to generalized correlations. According to the comparison of projected data with the outcomes of earlier experiments, the derived model’s performance was validated and the findings showed outstanding accuracy.

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Section: Introductionsupporting

confidence: 75%

Artificial neural networks application on average and stagnation Nusselt number prediction for impingement cooling of flat plate with helically coiled air jet

Fawaz,

Osama,

Maghrabie

2023

Preprint

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“…In 2017 Guo et al [16] used digital particle image velocimetry method to analyse jet vertex phenomena for confined flow. In 2017 Attalla [17] used a square jet to study the uniformity of heat transfer on a flat surface and the results show 10.7% better uniformity in heat transfer when compared to the circular jet. In 2017 Muvvala et al [18] carried experimental study to understand the fluid flow and heat distribution on a flat plate by impinging jet from a square nozzle (perforated nozzles).…”

Section: Introductionmentioning

confidence: 99%

Study of Wall Static Pressure Distribution on Flat Surface by Impinging Submerged Jet from Non-circular Orifice

Hanchinal¹,

Patil²,

Katti³

2021

IJAME

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The distribution of wall static and stagnation (CP and CPO) pressure coefficient on a flat rectangular element by impinging air jet from the hexagonal orifice is obtained from experimentation. The past research studies helped to identify key parameters such as orifice geometry, jet exit-to-plate-distance (Z/dj), test section inclination (θ), jet Reynold number (Re), lateral distance-to-jet diameter (X/dj), test surface type and geometry, for better and acceptable results. The experimental outcome helps to know the effect of identified key parameters on wall static and stagnation pressure on a rectangular test plate in a confined flow path. The independent nature of wall static pressure is observed for all jet Reynold number (10000 ≤ Re ≤ 50000). Higher pressure coefficient values were observed at lower Z/dj = 1, X/dj = 0 and θ = 0. A significant drop in CP values are seen with the increase in Z/dj, X/dj and θ. The experimental CP and CPO contribution of confined flow are compared against the unconfined flow, around 48% to 58% enhancement is observed when confinement is used. Experimental pressure drop measurements across orifice were made and pressure loss coefficient (PC) for hexagonal orifice of confined and unconfined condition are reported.

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“…Influence of the nozzle shapes, the heat transfer distribution over the target surface of jet impingement was investigated by testing two in-line jet arrays of square and circular nozzle shape [21], [22]. The impinging circular jet array gained 8% higher heat transfer rate than the square jet array.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of heat transfer and flow characteristics of a double-wall cooling structure: Reverse circular jet impingement

Ahmed

Wright

Abdel-Aziz

et al. 2021

Applied Thermal Engineering

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Influence of the nozzle shape on heat transfer uniformity for in-line array of impinging air jets

Cited by 36 publications

References 30 publications

Artificial neural networks application on average and stagnation Nusselt number prediction for impingement cooling of flat plate with helically coiled air jet

Artificial neural networks application on average and stagnation Nusselt number prediction for impingement cooling of flat plate with helically coiled air jet

Study of Wall Static Pressure Distribution on Flat Surface by Impinging Submerged Jet from Non-circular Orifice

Numerical investigation of heat transfer and flow characteristics of a double-wall cooling structure: Reverse circular jet impingement

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