A note on the heat transfer characteristics of circular impinging jet

Pamadi, Bandu N.; Белов, И. А.

doi:10.1016/0017-9310(80)90032-0

Cited by 25 publications

(4 citation statements)

References 5 publications

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“…Pamadi and Belov [1] observed two prominent secondary peaks for the lower nozzle-target (Z/d) spacing. The first peak was concluded due to the transition in flow regime and the second due to non-uniform turbulence.…”

Section: Literature Overview and Scope Of Present Workmentioning

confidence: 99%

On numerical investigation of heat transfer augmentation of flat target surface under impingement of steady air jet for varying heat flux boundary condition

Siddique

Ashfaq²,

Khan

et al. 2021

J Therm Anal Calorim

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The prediction of flow pattern for the proposed range of Reynolds number and nozzle-target spacing is carried out using SST + Gamma-Theta turbulence model. The simulations of the flow field in a computational domain are carried out using CFX as a base solver with 10 −6 being the converging criteria. The present work aims to determine the local Nusselt number magnitude for varying heat flux input boundary conditions. Not only this, the impinging Reynolds numbers and nozzle-target spacing are also varied to record sufficient data, enough to predict a semi-empirical correlation. The proposed correlation for calculating the cooling characteristic (Nusselt number magnitude) under the impingement of air jet is presented in terms of profile heat flux parameter, impinging Reynolds number, and target to nozzle exit spacing. The corresponding mathematical parameter representing the profile heat flux boundary condition is the slope in heat flux magnitude versus the target surface's radial distance. The Nusselt number profile, which describes the cooling characteristic under different impinging Reynolds numbers and nozzle-target spacing, initially increases, takes a peek, and decreases. The rise in the cooling rate near the stagnation region is due to the turbulence palpitation, resulting from imbalance adverse pressure gradient and onset transition of Reynolds number. The local heat transfer under such boundary conditions increases with nozzle-target spacing and least depends on Reynolds number. However, the Nusselt profile for a constant heat flux magnitude but varying slope (non-uniform) shows an enhancement with a decrease in the slope from unit value.

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Section: Literature Overview and Scope Of Present Workmentioning

confidence: 99%

On numerical investigation of heat transfer augmentation of flat target surface under impingement of steady air jet for varying heat flux boundary condition

Siddique

Ashfaq²,

Khan

et al. 2021

J Therm Anal Calorim

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show abstract

“…The implication is that the mixing-induced turbulence has not penetrated the potential core of the jet at this small plate spacing. Pamadi et al (1980) investigated theoretically the effect on heat transfer of the ring of high turbulence from the jet boundary shear layer. They computed a circle of elevated heat transfer at about 0.5d from the stagnation point for z/d = 4 for an unconfined, fully developed jet.…”

Section: Jet Radial Heat Transfer Profilesmentioning

confidence: 99%

Local Heat Transfer Coefficient and Adiabatic Wall Temperature Measurement Beneath Arrays of Staggered and Inline Impinging Jets

Treuren

Wang

Ireland

et al. 1994

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration

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Recent work, Van Treuren et al. (1993), has shown the transient method of measuring heat transfer under an array of impinging jets allows the determination of local values of adiabatic wall temperature and heat transfer coefficient over the complete surface of the target plate. Using this technique, an inline array of impinging jets has been tested over a range of average jet Reynolds numbers (10,000–40,000) and for three channel height to jet hole diameter ratios (1, 2, and 4). The array is confined on three sides and spent flow is allowed to exit in one direction. Local values are averaged and compared with previously published data in related geometries. The current data for a staggered array is compared to those from an inline array with the same hole diameter and pitch for an average jet Reynolds number of 10,000 and channel height to diameter ratio of one. A comparison is made between intensity and hue techniques for measuring stagnation point and local distributions of heat transfer. The influence of the temperature of the impingement plate through which the coolant gas flows on the target plate heat transfer has been quantified.

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“…Many workers (Obot et at, 1982, Gardon andAfrikat, 1965) have observed a local peak in heat transfer on the target surface in the range 0.5-1d from the stagnation point. While some workers (Koopman andSparrow, 1976, Obot et at, 1979) have attributed this to a local thinning of the boundary layer, Pamadi and Belov (1980) showed that a peak at this position could be caused by the turbulence profile of the impinging jet. In region 4, the wall jet, the initial acceleration can no longer be sustained, since the flow must slow down to satisfy continuity A second peak in heat transfer where this acceleration reduces, measured at 1.5 -2.5d from the stagnation point (for example by Obot et at, 1979, Van Treuren, 1994, Lucas, 1992, is thought to be a result of transition to a turbulent boundary layer.…”

Section: Introductionmentioning

confidence: 97%

A Comparison of Full Surface Local Heat Transfer Coefficient and Flow Field Studies Beneath Sharp-Edged and Radiused Entry Impinging Jets

Gillespie

Guo

Wang

et al. 1996

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration

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Full heat transfer coefficient and static pressure distributions have been measured on the target surface under impinging jets formed by sharp-edged and large entry radius holes. These geometries are representative of impingement holes in a gas turbine blade manufactured by laser cutting and by casting, respectively. Target surface heat transfer has been measured in a large scale perspex rig using both the transient liquid crystal technique and hot thin film gauges. A range of jet Reynolds numbers, representative of engine conditions, has been investigated. The velocity variation has been calculated from static pressure measurements on the impingement target surface. The heat transfer to the target surface is discussed in terms of the interpreted flow field.

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A note on the heat transfer characteristics of circular impinging jet

Cited by 25 publications

References 5 publications

On numerical investigation of heat transfer augmentation of flat target surface under impingement of steady air jet for varying heat flux boundary condition

On numerical investigation of heat transfer augmentation of flat target surface under impingement of steady air jet for varying heat flux boundary condition

Local Heat Transfer Coefficient and Adiabatic Wall Temperature Measurement Beneath Arrays of Staggered and Inline Impinging Jets

A Comparison of Full Surface Local Heat Transfer Coefficient and Flow Field Studies Beneath Sharp-Edged and Radiused Entry Impinging Jets

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