Prediction of Surface Temperature and Heat Flux of a Microelectronic Chip With Jet Impingement Cooling

1990 ◽  
Vol 112 (1) ◽  
pp. 57-62 ◽  
Author(s):  
X. S. Wang ◽  
Z. Dagan ◽  
L. M. Jiji
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Temperature ◽  
Transfer Problem ◽  
Jet Impingement ◽  
Lower Surface ◽  
Water Jet ◽  
Uniform Heat Flux ◽  
Impingement Cooling ◽  
Jet Cooling

In this paper, a previously developed analytic solution is applied to the conjugate heat transfer problem of jet impingement cooling of a microelectronic chip. The analysis is used to predict the surface temperature and heat flux distributions of a chip cooled by a laminar impinging FC-77 liquid or water jet with uniform heat flux dissipation at the heated bottom of the chip. Results are presented for two jet diameters of 0.5 and 1 mm. It is shown that, for a constant Reynolds number, the surface temperature is lower when the jet diameter is smaller. On the other hand, when the jet diameter is increased, the surface temperature and heat flux distributions are more uniform. Water jet impingement cooling shows much lower surface temperature and much higher heat transfer coefficient than FC-77 jet cooling. The thermal resistance for FC-77 liquid jet is 6 times larger than that for a water jet.

Impinging Jet Cooling Optimization for Obtaining Uniform Heat Flux

2010 ◽  
Author(s):  
Farshad Kowsary ◽  
Hamed Gholamian ◽  
Mehran Rajaeeian Hoonejani
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Transfer Problem ◽  
Jet Impingement ◽  
Separation Distance ◽  
Uniform Heat Flux ◽  
Target Plate ◽  
Steady State Condition ◽  
Uniform Heat ◽  
Impingement Heat Transfer

In this study obtaining a uniform heat flux over a target surface was investigated by means of using characteristics of jet impingement heat transfer. Conjugate Gradients Method (CGM) was utilized to minimize the objective function defined on the basis of the squared differences between the target heat flux and the calculated ones. Design variables were taken to be jets’ Reynolds numbers, separation distance between the exit plane of the jets and the target plate, as well as inter-jet spacing. Air single phase jets were used in this study. The problem was solved for the cases of 4 and 6 jets. Temperature difference between the jet exit and the target plate is 100°C, and a steady state condition was assumed. The Finite Volume Method and an unstructured mesh were used for direct solution of the jet impingement heat transfer problem for a laminar jets impingement to a flat plate with constant temperature.

Heat Transfer Characteristics of Downward Facing Hot Horizontal Surfaces Using Mist Jet Impingement

2017 ◽  
Author(s):  
Ashutosh Kumar Yadav ◽  
Parantak Sharma ◽  
Avadhesh Kumar Sharma ◽  
Mayank Modak ◽  
Vishal Nirgude ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Cooling System ◽  
Water Pressure ◽  
Jet Impingement ◽  
Surface Heat ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Transfer Characteristics

Impinging jet cooling technique has been widely used extensively in various industrial processes, namely, cooling and drying of films and papers, processing of metals and glasses, cooling of gas turbine blades and most recently cooling of various components of electronic devices. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. Controlled cooling, as an important procedure of thermal-mechanical control processing technology, is helpful to improve the microstructure and mechanical properties of steel. In industries for heat transfer efficiency and homogeneous cooling performance which usually requires a jet impingement with improved heat transfer capacity and controllability. It provides better cooling in comparison to air. Rapid quenching by water jet, sometimes, may lead to formation of cracks and poor ductility to the quenched surface. Spray and mist jet impingement offers an alternative method to uncontrolled rapid cooling, particularly in steel and electronics industries. Mist jet impingement cooling of downward facing hot surface has not been extensively studied in the literature. The present experimental study analyzes the heat transfer characteristics a 0.15mm thick hot horizontal stainless steel (SS-304) foil using Internal mixing full cone (spray angle 20 deg) mist nozzle from the bottom side. Experiments have been performed for the varied range of water pressure (0.7–4.0 bar) and air pressure (0.4–5.8 bar). The effect of water and air inlet pressures, on the surface heat flux has been examined in this study. The maximum surface heat flux is achieved at stagnation point and is not affected by the change in nozzle to plate distance, Air and Water flow rates.

Submerged Jet Impingement Boiling on a Polished Silicon Surface

2011 ◽  
Author(s):  
Preeti Mani ◽  
Ruander Cardenas ◽  
Vinod Narayanan
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Silicon Surface ◽  
High Speed ◽  
Jet Impingement ◽  
Working Fluid ◽  
Uniform Heat Flux ◽  
Submerged Jet ◽  
Jet Impingement Boiling

Submerged jet impingement boiling has the potential to enhance pool boiling heat transfer rates. In most practical situations, the surface could consist of multiple heat sources that dissipate heat at different rates resulting in a surface heat flux that is non-uniform. This paper discusses the effect of submerged jet impingement on the wall temperature characteristics and heat transfer for a non-uniform heat flux. A mini-jet is caused to impinge on a polished silicon surface from a nozzle having an inner diameter of 1.16 mm. A 25.4 mm diameter thin-film circular serpentine heater, deposited on the bottom of the silicon wafer, is used to heat the surface. Deionized degassed water is used as the working fluid and the jet and pool are subcooled by 20°C. Voltage drop between sensors leads drawn from the serpentine heater are used to identify boiling events. Heater surface temperatures are determined using infrared thermography. High-speed movies of the boiling front are recorded and used to interpret the surface temperature contours. Local heat transfer coefficients indicate significant enhancement upto radial locations of 2.6 jet diameters for a Reynolds number of 2580 and upto 6 jet diameters for a Reynolds number of 5161.

Design of a Mobile Probe to Predict Convection Heat Transfer on Building Integrated Photovoltaic (BIPV) at University of Technology Sydney (UTS)

2015 ◽  
Author(s):  
Jafar Madadnia
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Temperature ◽  
Simple Technique ◽  
Convection Heat Transfer ◽  
Thermal Design ◽  
Uniform Heat Flux ◽  
Convection Heat ◽  
Empirical Correlations ◽  
Building Integrated Photovoltaic

In the absence of a simple technique to predict convection heat transfer on building integrated photovoltaic (BIPV) surfaces, a mobile probe with two thermocouples was designed. Thermal boundary layers on vertical flat surfaces of a photovoltaic (PV) and a metallic plate were traversed. The plate consisted of twelve heaters where heat flux and surface temperature were controlled and measured. Uniform heat flux condition was developed on the heaters to closely simulate non-uniform temperature distribution on vertical PV modules. The two thermocouples on the probe measured local air temperature and contact temperature with the wall surface. Experimental results were presented in the forms of local Nusselt numbers versus Rayleigh numbers “Nu=a * (Ra)b”, and surface temperature versus dimensionless height [Ts -T∞= c*(z/h)d]. The constant values for “a”, “b”, “c” and “d” were determined from the best curve-fitting to the power-law relation. The convection heat transfer predictions from the empirical correlations were found to be in consistent with those predictions made by a number of correlations published in the open literature. A simple technique is then proposed to employ two experimental data from the probe to refine empirical correlations as the operational conditions change. A flexible technique to update correlations is of prime significance requirement in thermal design and operation of BIPV modules. The work is in progress to further extend the correlation to predict the combined radiation and convection on inclined PVs and channels.

Effect of Subcooling and Nozzle Diameter on Heat Transfer Characteristics of Downward Facing Hot Surfaces Using Mist Jet

2018 ◽  
Author(s):  
Avadhesh Kumar Sharma ◽  
Monika Meena ◽  
Anirudh Soni ◽  
Santosh K. Sahu
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Stagnation Point ◽  
Surface Heat Flux ◽  
Jet Impingement ◽  
Surface Heat ◽  
Nozzle Diameter ◽  
Initial Surface ◽  
Ir Camera ◽  
Impingement Cooling

The jet impingement cooling is always preferred over the other cooling methods due to its high heat removal capability. However, rapid quenching may lead to the formation of cracks and poor ductility to the quenched surface. Mist jet impingement cooling offers an alternative method to uncontrolled rapid cooling, particularly in steel and electronic industries. In mist cooling, the droplets are atomized by compressed air. Experiments are performed under transient conditions using two full-cone spray nozzles (Lechler Pneumatic atomizing nozzle 136.115.xx.A2 and 136.134.xx.A2) to study the effect of subcooling and nozzle diameter on surface heat flux. The hot surface used for the experiment is a stainless steel foil (AISI-304) of thickness 0.15mm. The initial surface temperature of the plate is maintained at 500±10°C with the help of an AC transformer. Infrared thermal image camera (A655sc, FLIR System) is used for data estimation. The IR camera and the nozzle are positioned on either side of the plate. The variation in surface temperature has been acquired at 8 different spatial points. It has been observed that that as we move away from the stagnation point then irrespective of air and water flow rates surface heat flux decreases. The maximum surface heat flux obtained at the stagnation point. With the increase in diameter surface heat flux increases irrespective of pressure values. The correlation between qm/qstag experimental and predicted values has been shown.

The Consequence of Target Surface Curvature in the Jet Impingement Cooling

2015 ◽  
Vol 766-767 ◽  
pp. 1148-1152
Author(s):  
M. Karthigairajan ◽  
S. Mohanamurugan ◽  
K. Umanath
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Convex Surface ◽  
Heated Surface ◽  
Jet Impingement ◽  
Target Surface ◽  
Uniform Heat Flux ◽  
Impingement Cooling ◽  
Air Jet ◽  
Increase With Increase

An experiment sturdy has been carried out for jet impingement cooling on the spherically convex surface is the development of mechanism. The effect of curvature, Space between jet exit and target surface, and Reynolds number on heat transfer is investigated for around air jet on hemispherical surface. The flow at the jet exit has fully developed velocity profile. A uniform heat flux boundary is created on the heated surface. The experiments are performed for 5000<Re<25000, 2<L/d<10, and jet diameters ranging from 1.3, 2.1, 3.4, 4.0 and 5.2 cm. In the mean time effect of curvature on local heat transfer is negligible at the wall jet region corresponding to r/d>0.5. From the experimental results the variation of the D/d ratio with local Nusselt number (Nust) for various Reynolds numbers and various L/d ratios are plotted. The results show that Nust increase with increase in curvature and the effect of the curvature will high at high Reynolds number. i.e. Nust at Re=25000 is 25% higher than at Re= 5000 This may be attributed to an increase in curvature increases acceleration, & size of three dimensional counter rotating vortices at stagnation point and the increment of Reynolds number increases the jet momentum, and also enhances the vortices creation. Nust is peaking in the L/d ratio of 6 because of high turbulence intensity as this distance.

Experimental Investigation of Jet Impingement Cooling With Carbon Dioxide at Supercritical Pressures

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Kai Chen ◽  
Rui-Na Xu ◽  
Pei-Xue Jiang
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Heat Flux ◽  
Stagnation Point ◽  
Jet Impingement ◽  
Supercritical Pressure ◽  
Inlet Temperature ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Transfer Characteristics

Jet impingement cooling is widely used in many industrial applications due to its high heat transfer capability and is an option for advanced high power density systems. Jet impingement cooling with supercritical pressure fluids could have much larger heat transfer rates combining with the large fluid specific heat near the pseudocritical point. However, the knowledge of its flow and heat transfer characteristics is limited. In this study, the flow and the local and average heat transfer characteristics of jet impingement cooling with supercritical pressure fluids were studied experimentally with carbon dioxide first. An integrated thermal sensor chip that provided heating and temperature measurements was manufactured using micro-electro-mechanical systems (MEMS) techniques with a low thermal conductivity substrate as the impingement cooled plate. The experiment system pressure was 7.85 MPa, which is higher than the critical pressure of carbon dioxide of 7.38 MPa. The mass flow rate ranged from 8.34 to 22.36 kg/h and the Reynolds number ranged from 19,000 to 68,000. The heat flux ranged from 0.02 to 0.22 MW/m2. The nozzle inlet temperature ranged from lower to higher than the pseudocritical temperature. Dramatic variations of the density at supercritical pressures near the heating chip were observed with increasing heat flux in the strong reflection and refraction of the backlight that disappeared at inlet temperatures higher than the pseudocritical temperature. The local heat transfer coefficient near the stagnation point increased with increasing heat flux while those far from the stagnation point increased to a maximum with increasing heat flux and then decreased due to the nonuniformity of jet impingement cooling. The heat transfer is higher at inlet temperatures lower than the pseudocritical temperature and the surface temperature is slightly higher than the pseudocritical temperature due to the dramatic changes in the fluid thermo-physical properties at supercritical pressures.

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