Heat-Transfer Optimization for Multichip Module Disks With an Unconfined Round Air Jet Impingement

2007 ◽  
Vol 129 (4) ◽  
pp. 411-420
Author(s):  
Y. C. Lee ◽  
C. J. Fang ◽  
M. C. Wu ◽  
C. H. Peng ◽  
Y. H. Hung
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Design Method ◽  
Jet Impingement ◽  
Separation Distance ◽  
Multichip Module ◽  
Programming Technique ◽  
Grashof Number ◽  
Round Jet ◽  
Air Jet

An effective method for performing the thermal optimization of stationary and rotating multichip module (MCM) disks with an unconfined round-jet impingement under space limitation constraint has been successfully developed. The design variables of stationary and rotating MCM disks with an unconfined round-jet impingement include the ratio of jet separation distance to nozzle diameter, Grashof number, jet Reynolds number, and rotational Reynolds number. The total experimental cases for stationary and rotating MCM disks are statistically designed by the central composite design method. In addition, a sensitivity analysis, the so-called analysis of variance, for the design factors has been performed. Among the influencing parameters, the jet Reynolds number dominates the thermal performance, while the Grashof number is found to have the least effect on heat-transfer performance for both stationary and rotating cases. Furthermore, the comparisons between the predictions by using the quadratic response surface methodology and the experimental data for both stationary and rotating cases are made with a satisfactory agreement. Finally, with the sequential quadratic programming technique, a series of thermal optimizations under multiconstraints—such as space, jet Reynolds number, rotational Reynolds number, nozzle exit velocity, disk rotational speed, and various power consumptions—has been systematically explored and discussed.

Thermal Optimal Design for Multichip Module Disks With an Unconfined Round-Jet Impingement

2005 ◽  
Author(s):  
C. J. Fang ◽  
M. C. Wu ◽  
C. H. Peng ◽  
Y. C. Lee ◽  
Y. H. Hung
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Steady State ◽  
Thermal Performance ◽  
Jet Impingement ◽  
Separation Distance ◽  
Grashof Number ◽  
Round Jet ◽  
Space Limitation

An effective method for performing the thermal optimization of stationary and rotating MCM disks with an unconfined round-jet impingement under space limitation constraint has been successfully developed. The design variables of stationary and rotating MCM disks with an unconfined round-jet impingement include: the ratio of jet separation distance to nozzle diameter (H/d), steady-state Grashof number (Grs), jet Reynolds number (Rej), rotational Reynolds number (Rer). The total experimental cases for stationary and rotating MCM disks are statistically designed by the Central Composite Design (CCD) method. In addition, a sensitivity analysis, the so-called ANOVA, for the design factors has been performed. In the stationary MCM disk with an unconfined round-jet impingement, the contribution percentage of jet Reynolds number on the thermal performance is 95.86%. The effect of jet Reynolds numbers on chip temperature distribution is more significant than that of the H/d ratio and steady-state Grashof number. In rotating MCM disk with an unconfined round-jet impingement, the effect of jet Reynolds number, which has the contribution percentage of 91.81%, dominates the thermal performance. Furthermore, the comparisons between the predictions by using the quadratic Response Surface Methodology (RSM) and the experimental data are made. The maximum deviations for transient stagnation Nusselt number and transient average Nusselt number for the cases of stationary MCM disk are 10.05% and 11.82%, respectively; and 9.41% and 12.44% for the cases of rotating MCM disk, respectively. Finally, with the Sequential Quadratic Programming (SQP) technique, a series of thermal optimal designs under space limitation constraint H/d≤12 has been efficiently performed. Comparisons between the numerical optimization results and the experimental data are made with a satisfactory agreement.

Heat Transfer Characteristics for a Confined Rotating MCM Disk With Round Jet Array Impingement

2007 ◽  
Author(s):  
C. Y. Lee ◽  
C. J. Fang ◽  
C. H. Peng ◽  
T. W. Lin ◽  
Y. H. Hung
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Steady State ◽  
Jet Impingement ◽  
Separation Distance ◽  
Heat Transfer Characteristics ◽  
Round Jet ◽  
Transfer Characteristics ◽  
Disk Rotation ◽  
Jet Array

An effective method of design of experiments combined with Central Composite Design for exploring the heat transfer characteristics for a confined rotating Multi-Chip Module (MCM) disk with round jet array impingement has been successfully developed. The relevant parameters influencing heat transfer performance include the steady-state Grashof number (Grs), ratio of jet separation distance to nozzle diameter (H/d), jet Reynolds number (Rej) and rotational Reynolds number (Rer). Their effects on heat transfer characteristics have been systematically explored. An axisymmetrical temperature distribution is ensured for various Grs, Rej, Rer and H/d ratios. As compared with the mutual effects of jet array impingement and disk rotation cause a more non-uniform distribution of chip temperatures. For heat transfer behavior, a new correlation of stagnation Nusselt number for jet array impingement at r/R = 0 in terms of Rej and H/d is presented. As compared with the experimental steady-state data of single round jet impingement, the average heat transfer enhancement at stagnation point r/R = 0 of jet array impingement is 607%. For the rotating MCM disk cases, the highest chip heat transfer occurs at the MCM disk rim, and decreases sharply along the distance from the surface edge toward the surface center.

Heat transfer of multi-slot nozzle air jet impingement with different Reynolds number

2020 ◽  
pp. 116470
Author(s):  
Jinqi Zhu ◽  
Ruifeng Dou ◽  
Ye Hu ◽  
Shixing Zhang ◽  
Xuyun Wang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Jet Impingement ◽  
Slot Nozzle ◽  
Air Jet

Experimental Investigation of Air–Water Mist Jet Impingement Cooling Over a Heated Cylinder

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Chunkyraj Khangembam ◽  
Dushyant Singh
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Stagnation Point ◽  
Jet Impingement ◽  
Water Mist ◽  
Heated Cylinder ◽  
Air Jet ◽  
The Heat Transfer Coefficient

Experimental investigation on heat transfer mechanism of air–water mist jet impingement cooling on a heated cylinder is presented. The target cylinder was electrically heated and was maintained under the boiling temperature of water. Parametric studies were carried out for four different values of mist loading fractions, Reynolds numbers, and nozzle-to-surface spacings. Reynolds number, Rehyd, defined based on the hydraulic diameter, was varied from 8820 to 17,106; mist loading fraction, f ranges from 0.25% to 1.0%; and nozzle-to-surface spacing, H/d was varied from 30 to 60. The increment in the heat transfer coefficient with respect to air-jet impingement is presented along with variation in the heat transfer coefficient along the axial and circumferential direction. It is observed that the increase in mist loading greatly increases the heat transfer rate. Increment in the heat transfer coefficient at the stagnation point is found to be 185%, 234%, 272%, and 312% for mist loading fraction 0.25%, 0.50%, 0.75%, and 1.0%, respectively. Experimental study shows identical increment in stagnation point heat transfer coefficient with increasing Reynolds number, with lowest Reynolds number yielding highest increment. Stagnation point heat transfer coefficient increased 263%, 259%, 241%, and 241% as compared to air-jet impingement for Reynolds number 8820, 11,493, 14,166, and 17,106, respectively. The increment in the heat transfer coefficient is observed with a decrease in nozzle-to-surface spacing. Stagnation point heat transfer coefficient increased 282%, 248%, 239%, and 232% as compared to air-jet impingement for nozzle-to-surface spacing of 30, 40, 50, and 60, respectively, is obtained from the experimental analysis. Based on the experimental results, a correlation for stagnation point heat transfer coefficient increment is also proposed.

Effect of Film Extraction on Impingement Heat Transfer Characteristics of Jet Arrays on Spherical-Dimpled Surfaces

2015 ◽  
Author(s):  
Xing Yang ◽  
Zhao Liu ◽  
Zhenping Feng
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Coupling Effect ◽  
Jet Impingement ◽  
Local Heat Transfer ◽  
Target Surface ◽  
Local Heat ◽  
Separation Distance ◽  
Plate Spacing

Detailed heat transfer distributions are numerically investigated on a multiple jet impingement target surface with staggered arrays of spherical dimples where coolant can be extracted through film holes for external film cooling. The three dimensional Reynolds-averaged Navier-Stokes analysis with SST k-ω turbulence model is conducted at jet Reynolds number from 15,000 to 35,000. The separation distance between the jet plate and the target surface varies from 3 to 5 jet diameters and two jet-induced crossflow schemes are included to be referred as large and small crossflow at one and two opposite exit openings correspondingly. Flow and heat transfer results for the dimpled target plate with three suction ratios of 2.5%, 5.0% and 12.0% are compared with those on dimpled surfaces without film holes. The results indicate the presence of film holes could alter the local heat transfer distributions, especially near the channel outlets where the crossflow level is the highest. The heat transfer enhancements by applying film holes to the dimpled surfaces is improved to different degrees at various suction ratios, and the enhancements depend on the coupling effect of impingement and channel flow, which is relevant to jet Reynolds number, jet-to-plate spacing and crossflow scheme.

Convective Heat Transfer From Heated Extended Surfaces With a Confined Slot Jet Impingement

2004 ◽  
Author(s):  
L. K. Liu ◽  
M. C. Wu ◽  
C. J. Fang ◽  
Y. H. Hung
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Reynolds Number ◽  
Mixed Convection ◽  
Average Nusselt Number ◽  
Jet Impingement ◽  
Separation Distance ◽  
Nusselt Numbers ◽  
Transfer Behavior ◽  
Extended Surfaces

A series of experimental investigations with stringent measurement methods on the studies related to mixed convection from the horizontally confined extended surfaces with a slot jet impingement have been successfully conducted. The relevant parameters influencing mixed convection performance due to jet impingement and buoyancy include the Grashof number, ratio of jet separation distance to nozzle width, ratio of extended surfaces height to nozzle width and jet Reynolds number. The range of these parameters studied are Grs = 3.77 × 105 – 1.84 × 106, H/W = 1–10, Hs/W = 0.74–3.40 and Re = 63–1383. In the study, the heat transfer behavior on the extended surfaces with confined slot jet impingement such as the temperature distribution, local and average Nusselt numbers on the extended surfaces has been systematically explored. The results manifest that the effect of steady-state Grashof number on heat transfer behavior such as stagnation, local and average Nusselt number is not significant; while the heat transfer performance increases with decreasing jet separation distance or with increasing extended surface height and jet Reynolds number. Besides, two new correlations of local and average Nusselt numbers in terms of H/W, Hs/W and Re are proposed for the cases of extended surfaces. A satisfactory agreement is achieved between the results predicted by these correlations and the experimental data. Finally, a complete composite correlation of steady-state average Nusselt number for mixed convection due to jet impingement and buoyancy is proposed. The comparison of the predictions evaluated by this correlation with all the present experimental data is made. The maximum and average deviations of the predictions from the experimental data are 7.46% and 2.87%, respectively.

Convective Heat Transfer From a Stationary or Rotating MCM Disk With a Unconfined Round Jet Impingement

2005 ◽  
Author(s):  
Y. M. Kuo ◽  
C. J. Fang ◽  
M. C. Wu ◽  
C. H. Peng ◽  
Y. H. Hung
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Steady State ◽  
Mixed Convection ◽  
Jet Impingement ◽  
Disk Surface ◽  
Separation Distance ◽  
Heat Flux Distribution ◽  
Disk Rotation ◽  
Nusselt Numbers

A series of experimental investigations with stringent measurement methods on the studies related to fluid flow and transient mixed convection from a horizontally unconfined stationary or rotating ceramic-based MCM disk with unconfined jet impingement have been successfully conducted. The relevant parameters influencing fluid flow and heat transfer performance are (1) mixed convection due to jet impingement and buoyancy: steady-state Grashof number, jet Reynolds number, and ratio of jet separation distance to nozzle diameter; and (2) mixed convection due to jet impingement, disk rotation and buoyancy: steady-state Grashof number, jet Reynolds number (Rej), rotational Reynolds number (Rer), ratio of jet separation distance to nozzle diameter (H/d). The thermal behavior explored includes the transient temperature distribution on the MCM disk surface, transient heat flux distribution of input power, transient convective heat flux distribution of chips, and transient chip and average heat transfer characteristics on the MCM disk surface. Besides, two new correlations of transient stagnation and average Nusselt numbers in terms of Rej, H/d and t are presented for the cases of stationary MCM disk. For the cases of rotating MCM disk, a new empirical correlation to classify two regimes of heat transfer modes such as disk rotation mode and jet impingement mode is presented; and a complete composite correlation of steady-state average Nusselt number for mixed convection due to jet impingement, disk rotation and buoyancy is proposed. As compared with the steady-state results, if the transient chip and average heat transfer behaviors may be considered as a superposition of a series of quasi-steady states, the transient chip and average Nusselt numbers in all the present transient experiments can be properly predicted by the existing steady-state correlations when t > 6 min in the power-on transient period.

Transient Convective Heat Transfer of Air Jet Impinging Onto a Confined Ceramic-Based MCM Disk

2001 ◽  
Author(s):  
W. S. Su ◽  
L. K. Liu ◽  
Y. H. Hung
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Jet Impingement ◽  
Disk Surface ◽  
Separation Distance ◽  
Transient Time ◽  
Nusselt Numbers ◽  
Air Jet ◽  
Transient Experiments ◽  
Transfer Behavior

Abstract Transient heat transfer behavior from a horizontally confined ceramic-based MCM disk with jet impingement has been systematically explored. The relevant parameters influencing heat transfer performance are the steady-state Grashof number, jet Reynolds number, and ratio of jet separation distance to nozzle diameter. In addition, an effective time, ton, representing a certain transient time when the mixed convection effect due to jet impingement and buoyancy becomes significant relative to heat conduction, is introduced. Both the transient chip and average Nusselt numbers on the MCM disk surface decrease with time in a very beginning period of 0 ≤ t < ton, whereas it gradually increases or keeps constant with time and finally approaches the steady-state value in the period of ton ≤ t < ts. As compared with the steady-state results, if the transient chip and average heat transfer behaviors may be considered as a superposition of a series of quasi-steady states, the transient chip and average Nusselt numbers in all the present transient experiments can be properly predicted by the existing steady-state correlations when t ≥ 4 min in the power-on transient period.

Heat Transfer Investigation with Multiple Jet Impingement

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Niranjan Murthy ◽  
B.K. Naveenkumar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Research Work ◽  
Jet Impingement ◽  
Test Surface ◽  
Simple Relationship ◽  
Flux Flow ◽  
Air Jets ◽  
Air Jet

An experimental study was carried out to study the effect of multiple jet impingement on a virtual electronic component using water and air as working fluids. It consists of an electrically heated test plate of size 20mm×20mm. Heat flux is varied between 25 to 250W/cm2 was dissipated using 0.25 and 0.5mm diameter jets placed in a 7×7 array with a pitch of 3mm. The difference in temperature between test surface and fluid inlet is within 30 degC for water jets and within 75 degC for air jet experiments. Experiments were conducted by changing the heat flux, flow rate and distance between the test surface and jet exit and [iv] horizontal and vertical positioning of the jets. It was found that heat flux, jet diameter and Reynolds number are important factors in determining the heat transfer. The effects of distance between test surface and jet exit [Z] and positioning of the jets were insignificant. Though the multiple jet impingement heat transfer problem is complex, the heat transfer results could be correlated using a simple relationship in the form of Nu = AqmRen. The constant (m) which indicates the effect of heat flux has the value of 0.8 and 0.9 depending upon the jet diameter and the coolant. The constant (n) which indicates the influence of Reynolds number has the value of 0.25 for both water and air jets. The value of constant (A) is different for water and air jets. The correlation developed in this research work can be effectively used to design multiple water and air jet cooling system for electronic components.

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