Design of Air-Cooled Heat Sink for a 55-kW Power Inverter With Laminar Flow

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Rao V. Arimilli ◽  
Ali Hossein Nejad ◽  
Kivanc Ekici
Keyword(s):  
Laminar Flow ◽  
Heat Sink ◽  
Cell Model ◽  
Numerical Models ◽  
Three Dimensional ◽  
Transfer Model ◽  
Simplified Approach ◽  
Maximum Surface ◽  
Thermal Requirements ◽  
Surface Temperatures

A methodology is developed for the design of an air-cooled 55-kW-rated inverter heat sink. The design constraints are that the power density (PD) must meet or exceed the values associated with liquid-cooled systems of the same power rating, and that the maximum surface temperatures be less than 200 °C. To keep the pressure drop low relative to turbulent flow designs, a laminar flow regime is chosen. A preliminary design that satisfies the PD constraint exactly, and the thermal requirements approximately, is determined. To ensure that the thermal requirements are met by the design configuration, a thermal-fluid analysis based on a three-dimensional conjugate heat transfer model is conducted. Overall, energy balance errors (OEBEs) as high as 15% were encountered in the numerical models. These errors are reduced by taking advantage of the symmetry between fins using a typical unit cell model. A new simplified approach for the simulations was identified which involved modeling fins as highly conductive layers instead of solid domains. This further reduced the OEBEs to less than 0.004%. The design factors considered in this study include effective cooling surface area, fin thickness, fin spacing, and fin height. The results show that the maximum surface temperatures can be kept below 200 °C for safe operation of SiC devices in the inverter module while increasing the PD.

A Numerical Study of the Thermal Performance of a Tape Ball Grid Array (TBGA) Package

1999 ◽  
Vol 122 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Sanjeev B. Sathe ◽  
Bahgat G. Sammakia
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Numerical Study ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Cover Plate ◽  
Transfer Model ◽  
Turbulence Regime ◽  
Chip Carrier ◽  
Internal Thermal Resistance

This paper deals with the thermal management of a TBGA chip carrier package. In TBGA packages the backside of the chip is available for heat sink or heat spreader (cover plate) attach. By attaching a heat sink directly to the chip and using a thin layer of high thermal conductivity adhesive, a very low internal thermal resistance can be achieved. The package is attached to an organic card and placed vertically in a channel. A three-dimensional conjugate heat transfer model is used, accounting for conduction and radiation in the package and card and convection in the surrounding air. A simplified turbulence model is developed to predict temperatures in the low Re turbulence regime. A parametric study is performed to evaluate the effects of card design, air velocities, interconnect thermal conductivities and thermal radiation on the chip junction temperatures. An experimental study was also conducted to verify the model. Even though the geometry is highly complex due to the multilayer construction of the module and the card, agreement between the model and the experimental measurement is excellent. It was shown that radiation heat transfer can be an equally significant mode as convection in the natural convection regime. [S1043-7398(00)01302-5]

Three-Dimensional Simulation of Thermoelectric Devices With Compact Numerical Models

2003 ◽  
Author(s):  
Eric Prather ◽  
Bhalchandra Puranik
Keyword(s):  
Heat Source ◽  
Heat Sink ◽  
Numerical Models ◽  
Three Dimensional ◽  
Electronics Cooling ◽  
Step Function ◽  
Compact Model ◽  
Zone Model ◽  
Detailed Model ◽  
Source Power

Thermoelectric cooling modules (TECs) are widely used within electronic equipment for both temperature reduction and control of individual components. The techniques presented in this paper demonstrate that it is possible to construct a simple three-zone model, that represents the transient and 3D properties of a typical TEC, and can be easily built within existing CFD software packages for a known electric current or voltage input. A comparison of compact model results, detailed model results, and experimental results is presented for a typical electronics cooling setup, including a heat source (from which heat is absorbed by the TEC), TEC device, and air-cooled heat sink. Variables examined include heat source power dissipation, TEC current, and heat sink airflow. Finally, the response of the setup to a step function in current is examined to investigate the transient performance of the compact model.

Solidification of Phase Change Material Nanocomposite Inside a Finned Heat Sink: A Macro Scale Model of Nanoparticles Distribution

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Santosh Kumar Sahoo ◽  
Prasenjit Rath ◽  
Mihir Kumar Das
Keyword(s):  
Numerical Model ◽  
Phase Change ◽  
Phase Change Material ◽  
Finite Volume ◽  
Heat Sink ◽  
Numerical Models ◽  
Scale Model ◽  
Transfer Model ◽  
Macro Scale ◽  
Change Material

The present work aims at developing a heat transfer model for phase change material nanocomposite (PCMNC)-based finned heat sink to study its heat rejection potential. The proposed model is developed in line with the binary alloy formulation for smaller size nanoparticles. The present study gives a more insight into the nanoparticle distribution while the nanocomposite is undergoing phase change. The nanocomposite is placed in the gap between the fins in a finned heat sink where solidification occurs from the top and lateral sides of fins. The proposed numerical model is based on finite volume method. Fully implicit scheme is used to discretize the transient terms in the governing transport equations. Natural convection in the molten nanocomposite is simulated using the semi-implicit-pressure-linked–equations-revised (SIMPLER) algorithm. Nanoparticle transport is coupled with the energy equation via Brownian and thermophoretic diffusion. Enthalpy porosity approach is used to model the phase change of PCMNC. Scheil rule is used to compute the nanoparticle concentration in the mixture consisting of solid and liquid PCMNC. All the finite volume discrete algebraic equations are solved using the line-by-line tridiagonal-matrix-algorithm with multiple sweeping from all possible directions. The proposed numerical model is validated with the existing analytical and numerical models. A comparison in thermal performance is made between the heat sink with homogeneous nanocomposite and with nonhomogeneous nanocomposite. Finally, the effect of spherical nanoparticles and platelet nanoparticles to the solidification behavior is compared.

scholarly journals A Proof-of-Concept Algorithm for the Retrieval of Total Column Amount of Trace Gases in a Multi-Dimensional Atmosphere

2021 ◽  
Vol 13 (2) ◽  
pp. 270
Author(s):  
Adrian Doicu ◽  
Dmitry S. Efremenko ◽  
Thomas Trautmann
Keyword(s):  
Trace Gases ◽  
Three Dimensional ◽  
Principal Component ◽  
Radiative Transfer Model ◽  
Computational Time ◽  
Transfer Model ◽  
Proof Of Concept ◽  
Discrete Ordinate ◽  
Distribution Method ◽  
Total Column

An algorithm for the retrieval of total column amount of trace gases in a multi-dimensional atmosphere is designed. The algorithm uses (i) certain differential radiance models with internal and external closures as inversion models, (ii) the iteratively regularized Gauss–Newton method as a regularization tool, and (iii) the spherical harmonics discrete ordinate method (SHDOM) as linearized radiative transfer model. For efficiency reasons, SHDOM is equipped with a spectral acceleration approach that combines the correlated k-distribution method with the principal component analysis. The algorithm is used to retrieve the total column amount of nitrogen for two- and three-dimensional cloudy scenes. Although for three-dimensional geometries, the computational time is high, the main concepts of the algorithm are correct and the retrieval results are accurate.

scholarly journals Experimental and Numerical Investigation of 3D Dam-Break Wave Propagation in an Enclosed Domain with Dry and Wet Bottom

2021 ◽  
Vol 11 (12) ◽  
pp. 5638
Author(s):  
Selahattin Kocaman ◽  
Stefania Evangelista ◽  
Hasan Guzel ◽  
Kaan Dal ◽  
Ada Yilmaz ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Dam Break ◽  
Dam Failure ◽  
Navier Stokes ◽  
Negative Wave ◽  
Through Flow ◽  
Instantaneous Removal ◽  
Surface Patterns

Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation under the influence of tailwater depth. This work presents three-dimensional (3D) numerical simulations of laboratory experiments of dam-breaks with tailwater performed at the Laboratory of Hydraulics of Iskenderun Technical University, Turkey. The dam-break wave was generated by the instantaneous removal of a sluice gate positioned at the center of a transversal wall forming the reservoir. Specifically, in order to understand the influence of tailwater level on wave propagation, three tests were conducted under the conditions of dry and wet downstream bottom with two different tailwater depths, respectively. The present research analyzes the propagation of the positive and negative wave originated by the dam-break, as well as the wave reflection against the channel’s downstream closed boundary. Digital image processing was used to track water surface patterns, and ultrasonic sensors were positioned at five different locations along the channel in order to obtain water stage hydrographs. Laboratory measurements were compared against the numerical results obtained through FLOW-3D commercial software, solving the 3D Reynolds-Averaged Navier–Stokes (RANS) with the k-ε turbulence model for closure, and Shallow Water Equations (SWEs). The comparison achieved a reasonable agreement with both numerical models, although the RANS showed in general, as expected, a better performance.

scholarly journals Study of Mini Channel Heat Sink with Different Internal Configuration

2020 ◽  
Vol 319 ◽  
pp. 02004
Author(s):  
Muhammad Akif Rahman ◽  
Md Badrath Tamam ◽  
Md Sadman Faruque ◽  
A.K.M. Monjur Morshed
Keyword(s):  
Nusselt Number ◽  
Thermal Performance ◽  
Heat Sink ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Rectangular Channels ◽  
Flow Through ◽  
Internal Configuration

In this paper a numerical analysis of three-dimensional laminar flow through rectangular channel heat sinks of different geometric configuration is presented and a comparison of thermal performance among the heat sinks is discussed. Liquid water was used as coolant in the aluminum made heat sink with a glass cover above it. The aspect ratio (section height to width) of rectangular channels of the mini-channel heat sink was 0.33. A heat flux of 20 W/cm2 was continuously applied at the bottom of the channel with different inlet velocity for Reynold’s number ranging from 150 to 1044. Interconnectors and obstacles at different positions and numbers inside the channel were introduced in order to enhance the thermal performance. These modifications cause secondary flow between the parallel channels and the obstacles disrupt the boundary layer formation of the flow inside the channel which leads to the increase in heat transfer rate. Finally, Nusselt number, overall thermal resistance and maximum temperature of the heat sink were calculated to compare the performances of the modified heat sinks with the conventional mini channel heat sink and it was observed that the heat sink with both interconnectors and obstacles enhanced the thermal performance more significantly than other configurations. A maximum of 36% increase in Nusselt number was observed (for Re =1044).

Ice-Phase Precipitation

2017 ◽  
Vol 58 ◽  
pp. 6.1-6.36 ◽  
Author(s):  
I. Gultepe ◽  
A. J. Heymsfield ◽  
P. R. Field ◽  
D. Axisa
Keyword(s):  
Collection Efficiency ◽  
Numerical Models ◽  
Mass Density ◽  
Three Dimensional ◽  
Phase Precipitation ◽  
Microphysical Parameters ◽  
Mass Size ◽  
Ice Water ◽  
Ice Phase

AbstractIce-phase precipitation occurs at Earth’s surface and may include various types of pristine crystals, rimed crystals, freezing droplets, secondary crystals, aggregates, graupel, hail, or combinations of any of these. Formation of ice-phase precipitation is directly related to environmental and cloud meteorological parameters that include available moisture, temperature, and three-dimensional wind speed and turbulence, as well as processes related to nucleation, cooling rate, and microphysics. Cloud microphysical parameters in the numerical models are resolved based on various processes such as nucleation, mixing, collision and coalescence, accretion, riming, secondary ice particle generation, turbulence, and cooling processes. These processes are usually parameterized based on assumed particle size distributions and ice crystal microphysical parameters such as mass, size, and number and mass density. Microphysical algorithms in the numerical models are developed based on their need for applications. Observations of ice-phase precipitation are performed using in situ and remote sensing platforms, including radars and satellite-based systems. Because of the low density of snow particles with small ice water content, their measurements and predictions at the surface can include large uncertainties. Wind and turbulence affecting collection efficiency of the sensors, calibration issues, and sensitivity of ground-based in situ observations of snow are important challenges to assessing the snow precipitation. This chapter’s goals are to provide an overview for accurately measuring and predicting ice-phase precipitation. The processes within and below cloud that affect falling snow, as well as the known sources of error that affect understanding and prediction of these processes, are discussed.

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