3D Compact Model of Packaged Thermoelectric Coolers

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Owen Sullivan ◽  
Borislav Alexandrov ◽  
Saibal Mukhopadhyay ◽  
Satish Kumar
Keyword(s):  
Steady State ◽  
Finite Volume ◽  
Thermal Contact ◽  
Transient Behavior ◽  
Compact Model ◽  
Transfer Coefficients ◽  
Thermoelectric Coolers ◽  
Electronic Package ◽  
Heat Transfer Coefficients ◽  
A Tec

Hotspots on a microelectronic package can severely hurt the performance and long-term reliability of the chip. Thermoelectric coolers (TECs) can provide site-specific and on-demand cooling of hot spots in microprocessors. We develop a 3D compact model for fast and accurate modeling of a TEC device integrated inside an electronic package. A 1D compact model of a TEC is first built in SPICE and validated for steady-state and transient behavior against a finite-volume model. The 1D compact model of the TEC is then incorporated into a 3D compact model of a prototype electronic package. The results from the compact model for the packaged TEC are in good agreement with a finite-volume based model, which confirms the compact model's ability to accurately model the TEC's interaction with the package. Analysis of packaged TECs using this 3D compact model shows that (i) moving TECs closer to the chip results in faster response time and an increase in maximum cooling, (ii) high thermal contact resistance within the thermoelectric cooler significantly degrades performance of the device, and (iii) higher convective heat transfer coefficients (HTC) at the heat spreader surface increase steady-state cooling but decrease maximum transient cooling.

Compact Model of Thermoelectric Coolers on a Micro-Electronic Chip

2011 ◽  
Author(s):  
Owen Sullivan ◽  
Borislav Alexandrov ◽  
Saibal Mukhopadhyay ◽  
Satish Kumar
Keyword(s):  
Steady State ◽  
Finite Volume ◽  
Hot Spots ◽  
Transient Behavior ◽  
Small Error ◽  
Compact Model ◽  
Thermoelectric Coolers ◽  
Electronic Package ◽  
Full Speed

Hot spots on a microelectronic package can severely hurt the performance and long-term reliability of the chip. Thermoelectric coolers (TECs) have been shown to potentially provide efficient site-specific on-demand cooling of hot spots in microprocessors. TECs could lengthen the amount of time a processor is capable of running at full speed in the short-term and also provide long-term reliability by creating a more uniform temperature distribution across the chip. We have created a compact model for fast and accurate modeling of the TEC device integrated inside an electronic package. A 1-D compact model for TEC is first built in SPICE and has been validated for steady-state and transient behavior against a finite-volume model. The 1-D model of TEC was then incorporated into compact model of a prototype electronic package and simulations were performed to validate its steady state and transient behavior. This integrated compact model’s results are in good agreement with a finite volume based model developed for TECs integrated inside a package and confirmed the compact model’s ability to accurately model the TEC’s interaction with package. The compact model has relatively small error when compared to the finite-volume based model and obtains results in a fraction of the time, reducing run-time in a transient simulation by 430%. A simple controller was added to the electronic package and TEC model to provide an initial test of how the compact model can aid design of more complex control systems to efficiently operate the thermoelectric coolers.

Analysis of automotive disc brake cooling characteristics

2003 ◽  
Vol 217 (8) ◽  
pp. 657-666 ◽  
Author(s):  
G P Voller ◽  
M Tirovic ◽  
R Morris ◽  
P Gibbens
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Thermal Contact ◽  
Thermal Power ◽  
Disc Brake ◽  
Transfer Coefficients ◽  
Fe Modelling ◽  
Heat Transfer Coefficients ◽  
Brake Application ◽  
Cfd Analyses

The aim of this investigation was to study automotive disc brake cooling characteristics experimentally using a specially developed spin rig and numerically using finite element (FE) and computational fluid dynamics (CFD) methods. All three modes of heat transfer (conduction, convection and radiation) have been analysed along with the design features of the brake assembly and their interfaces. The spin rig proved to be very valuable equipment; experiments enabled the determination of the thermal contact resistance between the disc and wheel carrier. The analyses demonstrated the sensitivity of this mode of heat transfer to clamping pressure. For convective cooling, heat transfer coefficients were measured and very similar results were obtained from spin rig experiments and CFD analyses. The nature of radiative heat dissipation implies substantial e ects at high temperatures. The results indicate substantial change of emissivity throughout the brake application. The influence of brake cooling parameters on the disc temperature has been investigated by FE modelling of a long drag brake application. The thermal power dissipated during the drag brake application has been analysed to reveal the contribution of each mode of heat transfer.

Using Thermoelectric Cooling With Tourniquets for Nerve Preservation

2016 ◽  
Author(s):  
M. Trupiano ◽  
S. Aarabi ◽  
A. F. Emery
Keyword(s):  
Thermal Conditions ◽  
Ambient Conditions ◽  
Transfer Coefficients ◽  
Thermoelectric Coolers ◽  
Ambient Temperatures ◽  
Nerve Preservation ◽  
Heat Transfer Coefficients ◽  
Surface Temperatures ◽  
Element Simulation ◽  
Free And Forced Convection

The use of a tourniquet leads to nerve damage, even if applied for short periods of time. This damage can be minimized if the limb is cooled. Because of the low conductivities of human tissue, core limb cooling is slow unless the surface temperature is very cool. Subzero surface temperatures can lead to skin injury (i.e., frostbite). Ideally one would adjust the limb surface temperatures as a function of time to maximize the cooling rate while avoiding permanent tissue damage. One possible approach is to use a thermoelectric cooler (TEC) in conjunction with a programmable power supply. TEC performance varies strongly with heat absorption rate, a function of limb thermal properties, and hot side temperatures that are strongly affected by the surface conditions on the hot side, i.e., overall heat transfer coefficients and ambient conditions. The paper describes the use of finite element simulation to predict the usefulness of using thermoelectric coolers applied to the surface of a limb when compared to the standard approach of using ice packs. Since the TEC performance is strongly influenced by its warm side thermal conditions, experimental results are presented for different ambient temperatures, free and forced convection, and evaporation of water from a wickable covering.

The Impact of Fin Deformation on Condensation Heat Transfer Coefficients in Internally Grooved Tubes

2013 ◽  
Author(s):  
Sunil Mehendale
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Thermal Contact ◽  
Heat Pumps ◽  
Condensation Heat Transfer ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Condensing Heat Transfer ◽  
The Impact ◽  
Tube Expansion

In HVACR equipment, internally enhanced round tube (microfin) designs such as axial, cross-grooved, helical, and herringbone are commonly used to enhance the boiling and condensing performance of evaporators, condensers, and heat pumps. Typically, such tubes are mechanically expanded by a mandrel into a fin pack to create an interference fit between the tube outside surface and the fin collar to minimize the thermal contact resistance between tube and fin. However, during this expansion process, the internal enhancements undergo varying amounts of deformation, which degrades the in-tube thermal performance. Extensive data on condensing heat transfer coefficients in microfin tubes have been reported in the open literature. However, researchers have seldom used expanded tubes to acquire and report such data. Hence, it is always questionable to use such pristine tube data for designing heat exchangers and HVACR systems. Furthermore, the HVACR industry has been experiencing steeply rising copper costs, and this trend is expected to continue in coming years. So, many equipment manufacturers and suppliers are actively converting tubes from copper to aluminum. However, because of appreciable differences between the material properties of aluminum and copper, as well as other manufacturing variables, such as mandrel dimensions, lubricant used, etc., tube expansion typically deforms aluminum fins more than copper fins. Based on an analysis of the surface area changes arising from tube expansion, and an assessment of the best extant in-tube condensation heat transfer correlations, this work proposes a method of estimating the impact of tube expansion on in-tube condensation heat transfer. The analysis leads to certain interesting and useful findings correlating fin geometry and in-tube condensation thermal resistance. This method can then be applied to more realistically design HVACR heat exchangers and systems.

Analysis of heat transfer between solids at low temperatures

1976 ◽  
Vol 54 (17) ◽  
pp. 1749-1771 ◽  
Author(s):  
J. D. N. Cheeke ◽  
H. Ettinger ◽  
B. Hebral
Keyword(s):  
Heat Transfer ◽  
Thermal Contact ◽  
Impedance Matching ◽  
Debye Model ◽  
Phonon Transport ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Critical Cone ◽  
Acoustic Mismatch ◽  
The Heat Transfer Coefficient

A detailed analysis is given of the acoustic mismatch formulation first given by Little for the thermal contact resistance between solids for the case of phonon transport in a Debye model. Extrema in the heat transfer coefficients as a function of the refractive index of the interface are shown to be due to either impedance matching conditions or to the presence of the critical cone. Detailed numerical tables are presented which permit rapid evaluation of the heat transfer coefficient to an accuracy of 5% or better.

Evaluation of a Hue Capturing Based Transient Liquid Crystal Method for High-Resolution Mapping of Convective Heat Transfer on Curved Surfaces

1993 ◽  
Vol 115 (2) ◽  
pp. 311-318 ◽  
Author(s):  
C. Camci ◽  
K. Kim ◽  
S. A. Hippensteele ◽  
P. E. Poinsatte
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Steady State ◽  
Liquid Crystals ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Bottom Surface ◽  
Curved Surfaces ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Accurate determination of convective heat transfer coefficients on complex curved surfaces is essential in the aerothermal design and analysis of propulsion system components. The heat transfer surfaces are geometrically very complex in most of the propulsion applications. This study focuses on the evaluation of a hue capturing technique for the heat transfer interpretation of liquid crystal images from a complex curved heat transfer surface. Impulsively starting heat transfer experiments in a square to rectangular transition duct are reported. The present technique is different from existing steady-state hue capturing studies. A real-time hue conversion process on a complex curved surface is adopted for a transient heat transfer technique with high spatial resolution. The study also focuses on the use of encapsulated liquid crystals with narrow color band in contrast to previous steady-state hue based techniques using wide band liquid crystals. Using a narrow band crystal improves the accuracy of the heat transfer technique. Estimated uncertainty for the heat transfer coefficient from the technique is about 5.9 percent. A complete heat transfer map of the bottom surface was possible using only seven liquid crystal image frames out of the 97 available frames during the transient experiment. Significant variations of heat transfer coefficients are quantitatively visualized on the curved surfaces of the transition duct.

Heat Transfer and Film Cooling Effectiveness in a Linear Airfoil Cascade

1997 ◽  
Vol 119 (2) ◽  
pp. 302-309 ◽  
Author(s):  
N. Abuaf ◽  
R. Bunker ◽  
C. P. Lee
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Film Cooling ◽  
Leading Edge ◽  
Transfer Coefficients ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Linear Cascade ◽  
Heat Transfer Coefficients

A warm (315°C) wind tunnel test facility equipped with a linear cascade of film cooled vane airfoils was used in the simultaneous determination of the local gas side heat transfer coefficients and the adiabatic film cooling effectiveness. The test rig can be operated in either a steady-state or a transient mode. The steady-state operation provides adiabatic film cooling effectiveness values while the transient mode generates data for the determination of the local heat transfer coefficients from the temperature–time variations and of the film effectiveness from the steady wall temperatures within the same aerothermal environment. The linear cascade consists of five airfoils. The 14 percent cascade inlet free-stream turbulence intensity is generated by a perforated plate, positioned upstream of the airfoil leading edge. For the first transient tests, five cylinders having roughly the same blockage as the initial 20 percent axial chord of the airfoils were used. The cylinder stagnation point heat transfer coefficients compare well with values calculated from correlations. Static pressure distributions measured over an instrumented airfoil agree with inviscid predictions. Heat transfer coefficients and adiabatic film cooling effectiveness results were obtained with a smooth airfoil having three separate film injection locations, two along the suction side, and the third one covering the leading edge showerhead region. Near the film injection locations, the heat transfer coefficients increase with the blowing film. At the termination of the film cooled airfoil tests, the film holes were plugged and heat transfer tests were conducted with non-film cooled airfoils. These results agree with boundary layer code predictions.

Determination of Heat Transfer Coefficients Using a 1-D Flow Model Applied to Irregular Shaped Cooling Channels in Pressure Diecasting

1999 ◽  
Vol 122 (4) ◽  
pp. 678-690 ◽  
Author(s):  
L. D. Clark ◽  
K. Davey ◽  
I. Rosindale ◽  
S. Hinduja
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Flow Model ◽  
Die Casting ◽  
Casting Machine ◽  
Transfer Coefficients ◽  
Element Mesh ◽  
Cooling Channels ◽  
Heat Transfer Coefficients ◽  
Effective Heat

A mesh partitioning strategy is presented which facilitates the application of boundary conditions to irregular shaped cooling channels in the pressure diecasting process. The strategy is used to partition a boundary element mesh, but can also be applied to the surface of a cooling channel bounded by a finite element mesh. The partitioning of the mesh into a series of element packs enables a one-dimensional flow model to be applied to the coolant. The flow model is used in conjunction with a steady-state thermal model which initially assumes that no boiling is taking place on the die/coolant interface. Values of bulk temperature, pressure, and velocity in the coolant are thus ascertained. This information, together with die temperatures, is then used in empirical relationships which model the various heat transfer mechanisms, including nucleate and transitional film boiling, between die and coolant. Effective heat transfer coefficients are calculated and applied at the die/coolant interface. The steady-state thermal code and the empirical boiling model are then used iteratively until stable values for the effective heat transfer coefficients are obtained. The models are tested by casting a small thin component using a die with conventional cooling channels and also using a novel die with irregular shaped cooling channels running on a hot chamber proprietary die casting machine. Simulation results are shown and experimental results using the hot chamber pressure die casting machine are reported. [S1087-1357(00)02302-9]

Heat Transfer and Film Cooling Effectiveness in a Linear Airfoil Cascade

1995 ◽  
Author(s):  
N. Abuaf ◽  
R. Bunker ◽  
C. P. Lee
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Film Cooling ◽  
Leading Edge ◽  
Transfer Coefficients ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Linear Cascade ◽  
Heat Transfer Coefficients

A warm (315 C) wind tunnel test facility equipped with a linear cascade of film cooled vane airfoils was used in the simultaneous determination of the local gas side heat transfer coefficients and the adiabatic film cooling effectiveness. The test rig can be operated in either a steady-state or a transient mode. The steady-state operation provides adiabatic film cooling effectiveness values while the transient mode generates data for the determination of the local heat transfer coefficients from the temperature-time variations and of the film effectiveness from the steady wall temperatures within the same aero-thermal environment. The linear cascade consists of five airfoils. The 14% cascade inlet free stream turbulence intensity is generated by a perforated plate, positioned upstream of the airfoil leading edge. For the first transient tests, five cylinders having roughly the same blockage as the initial 20% axial chord of the airfoils were used. The cylinder stagnation point heat transfer coefficients compare well with values calculated from correlations. Static pressure distributions measured over an instrumented airfoil agree with inviscid predictions. Heat transfer coefficients and adiabatic film cooling effectiveness results were obtained with a smooth airfoil having three separate film injection locations, two along the suction side, and the third one covering the leading edge showerhead region. Near the film injection locations, the heat transfer coefficients increase with the blowing film. At the termination of the film cooled airfoil tests, the film holes were plugged and heat transfer tests were conducted with non-film cooled airfoils. These results agree with boundary layer code predictions.

Modeling of the Two-Phase Closed Thermosyphon

1987 ◽  
Vol 109 (3) ◽  
pp. 722-730 ◽  
Author(s):  
J. G. Reed ◽  
C. L. Tien
Keyword(s):  
Steady State ◽  
Analysis Tool ◽  
Governing Equations ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Proposed Model ◽  
The Times ◽  
Steady State Solutions ◽  
Liquid And Vapor Phases

A comprehensive model is developed to predict the steady-state and transient performance of the two-phase closed thermosyphon. One-dimensional governing equations for the liquid and vapor phases are developed using available correlations to specify the shear stress and heat transfer coefficients. Steady-state solutions agree well with thermosyphon flooding data from several sources and with film thickness data obtained in the present investigation. While no data are available with which to compare the transient analysis, the results indicate that, for most systems, the governing time scale for system transients is the film residence time, which is typically much longer than the times required for viscous and thermal diffusion through the film. The proposed model offers a versatile and comprehensive analysis tool which is relatively simple.

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