HYBRID SYNTHETIC JET INTENDED FOR ENHANCED JET IMPINGEMENT HEAT/MASS TRANSFER

Equipment ◽  
2006 ◽  
Author(s):  
Zdenek Travnicek ◽  
Tomas Vit
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Jet Impingement ◽  
Synthetic Jet

Characterization of Impingement Heat/Mass Transfer to the Synthetic Jet Generated by a Biomimetic Actuator

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Zdeněk Trávníček ◽  
Zuzana Broučková
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Mass Transfer Rate ◽  
Jet Impingement ◽  
Flux Measurement ◽  
Impinging Jets ◽  
Synthetic Jet ◽  
Working Fluid ◽  
Naphthalene Sublimation Technique ◽  
Flexible Diaphragm

Two biomimetic synthetic jet (SJ) actuators were designed, manufactured, and tested under conditions of a jet impingement onto a wall. Nozzles of the actuators were formed by a flexible diaphragm rim, the working fluid was air, and the operating frequencies were chosen near the resonance at 65 Hz and 69 Hz. Four experimental methods were used: phase-locked visualization of the oscillating nozzle lips, jet momentum flux measurement using a precision scale, hot-wire anemometry, and mass transfer measurement using the naphthalene sublimation technique. The results demonstrated possibilities of the proposed actuators to cause a desired heat/mass transfer distribution on the exposed wall. It was concluded that the heat/mass transfer rate was commensurable with a conventional continuous impinging jets (IJs) at the same Reynolds numbers.

Local heat/mass transfer of array jet impingement cooling with pin-fin heat sinks

2021 ◽  
pp. 1-1
Author(s):  
Taehyun Kim ◽  
Eui Yeop Jung ◽  
Seungyeong Choi ◽  
Hee Seung Park ◽  
Changyong Lee ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Jet Impingement ◽  
Local Heat ◽  
Heat Sinks ◽  
Impingement Cooling ◽  
Pin Fin

Heat (Mass) Transfer for Circular Jet Impingement on a Confined Disk With Annular Collection of the Spent Air

1987 ◽  
Vol 109 (2) ◽  
pp. 329-335 ◽  
Author(s):  
E. M. Sparrow ◽  
Z. X. Xu ◽  
L. F. A. Azevedo
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat Mass Transfer ◽  
Jet Impingement ◽  
Separation Distance ◽  
Complete Collection ◽  
Precise Control ◽  
Maximum Value ◽  
Optimum Separation

Heat (mass) transfer experiments have been performed for a single circular jet impinging perpendicular to a confined disk, with the spent air being collected in an annulus which surrounds the jet delivery tube. This configuration provides precise control of the surface area affected by the impinging jet and also assures complete collection of the spent air. During the course of the experiments, parametric variations were made of the dimensionless separation distance between the jet origin and the impingement disk, of the ratio of disk diameter to the jet diameter, and of the Reynolds number. It was found that the heat (mass) transfer coefficient at the impingement surface increased substantially with a decrease in the jet diameter. Furthermore, for the smaller diameter jet, there was an optimum separation distance at which a maximum value of the heat (mass) transfer coefficient was achieved. For a jet of larger diameter, the transfer coefficient decreased monotonically as the separation distance increased.

Flow and Heat (Mass) Transfer Characteristics in an Impingement/Effusion Cooling System With Crossflow

2003 ◽  
Vol 125 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Dong Ho Rhee ◽  
Jong Hyun Choi ◽  
Hyung Hee Cho
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Cooling System ◽  
Jet Impingement ◽  
Impinging Jets ◽  
Hole Diameter ◽  
Jet Flows ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Transfer Characteristics

The present study is conducted to investigate flow and heat/mass transfer characteristics in an impingement/effusion cooling system with crossflow. To simulate the impingement/effusion cooling system, two perforated plates are placed in parallel and staggered arrangements with a gap distance of two times of the hole diameter, and initial crossflow passes between the plates. Both the injection and effusion hole diameters are 10 mm, and the Reynolds number based on the hole diameter and hole-to-hole pitch are fixed to 10,000 and six times of the hole diameter, respectively. To investigate the effect of crossflow, the flow rate of crossflow is changed from 0.5 to 2 times of that of the impinging jet, and the results of impingement/effusion cooling with crossflow are compared with those of the crossflow in the channel and of an array of impingement jets and the effusion cooling system. A naphthalene sublimation method is used to determine the local heat/mass transfer coefficients on the upward facing surface of the effusion plate. The flow patterns are calculated numerically using a commercial package. With the initial crossflow, the flow and heat/mass transfer characteristics are changed significantly from the results without the crossflow. Jet flows ejected from the injection plate are deflected by the crossflow, so that the stagnation points of the impinging jets move downstream. The heat/mass transfer rates on the effusion (target) plate decrease as the velocity of crossflow increases, since the crossflow induces the locally low transfer regions formed at the mid-way between the effusion holes. However, the impingement/effusion cooling with crossflow presents higher heat/mass transfer rates than the array jet impingement cooling with the same initial crossflow.

Flow and Heat (Mass) Transfer Characteristics in an Impingement/Effusion Cooling System With Crossflow

2002 ◽  
Author(s):  
Dong Ho Rhee ◽  
Jong Hyun Choi ◽  
Hyung Hee Cho
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Cooling System ◽  
Jet Impingement ◽  
Impinging Jets ◽  
Hole Diameter ◽  
Jet Flows ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Transfer Characteristics

The present study is conducted to investigate flow and heat/mass transfer characteristics in an impingement/effusion cooling system with crossflow. To simulate the impingement/effusion cooling system, two perforated plates are placed in parallel and staggered arrangements with a gap distance of 2 times of the hole diameter, and initial crossflow passes between the plates. Both the injection and effusion hole diameters are 10 mm, and the Reynolds number based on the hole diameter and hole-to-hole pitch are fixed to 10,000 and 6 times of the hole diameter, respectively. To investigate the effect of crossflow, the flow rate of crossflow is changed from 0.5 to 2 times of that of the impinging jet, and the results of impingement/effusion cooling with crossflow are compared with those of the crossflow in the channel and of an array of impingement jets and the effusion cooling system. A naphthalene sublimation method is used to determine the local heat/mass transfer coefficients on the upward facing surface of the effusion plate. The flow patterns are calculated numerically using a commercial package. With the initial crossflow, the flow and heat/mass transfer characteristics are changed significantly from the results without the crossflow. Jet flows ejected from the injection plate are deflected by the crossflow, so that the stagnation points of the impinging jets move downstream. The heat/mass transfer rates on the effusion (target) plate decrease as the velocity of crossflow increases, since the crossflow induces the locally low transfer regions formed at the mid-way between the effusion holes. However, the impingement/effusion cooling with crossflow presents higher heat/mass transfer rates than the array jet impingement cooling with the same initial crossflow.

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