Theta_JC Metrology Development: Fixture Design Modeling

2005 ◽  
Author(s):  
Michael Butch M. Dizon ◽  
Suzana Prstic ◽  
Sung-Won Moon
Keyword(s):  
Measurement Error ◽  
Heat Loss ◽  
Fluid Dynamic ◽  
Junction Temperature ◽  
Cfd Modeling ◽  
Design Parameters ◽  
Fixture Design ◽  
Power Modeling ◽  
Test Fixture ◽  
Probe Orientation

The junction-to-case thermal resistance or Theta_JC is one of the important metrics used to evaluate the performance and reliability of a particular electronic package. Currently, there is no established JEDEC standard for a Theta_JC test fixture. This paper presents the results of computational fluid dynamic (CFD) modeling studies carried out to propose a simple and robust Theta_JC fixture. The theoretical Theta_JC value for a particular package was first obtained assuming idealized conditions. The model was then modified to incorporate actual fixture conditions. The objective is to design a tester fixture that reduces the Theta_JC measurement error, i.e. ideal vs. fixture. The effect of various design parameters on the measured Theta_JC value was investigated. Sensitivity studies included cavity or insulation configuration, cold plate size, thermocouple probe orientation, thermal interface materials, and applied power. Modeling results showed that, regardless of the insulation design, there was considerable heat loss through the test board on which the package was mounted. This resulted in a lower Theta_JC value measured, with errors up to 30%. To reduce the heat loss and measurement error, a heater was mounted at the bottom of the board and maintained at a temperature within 1 to 2°C of the junction temperature. Using this simple approach, the measurement error was reduced to around 6%. From the results of the study, an optimized prototype fixture design is proposed.

scholarly journals Clogging sensitivity of flow distributors designed for radially elongated hexagonal pillar array columns: a computational modelling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farideh Haghighi ◽  
Zahra Talebpour ◽  
Amir Sanati-Nezhad
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Contact Zone ◽  
Separation Efficiency ◽  
Fluid Dynamic ◽  
Computational Modelling ◽  
Channel Width ◽  
Fluid Distribution ◽  
Design Parameters ◽  
Pillar Array

AbstractFlow distributor located at the beginning of the micromachined pillar array column (PAC) has significant roles in uniform distribution of flow through separation channels and thus separation efficiency. Chip manufacturing artifacts, contaminated solvents, and complex matrix of samples may contribute to clogging of the microfabricated channels, affect the distribution of the sample, and alter the performance of both natural and engineered systems. An even fluid distribution must be achieved cross-sectionally through careful design of flow distributors and minimizing the sensitivity to clogging in order to reach satisfactory separation efficiency. Given the difficulty to investigate experimentally a high number of clogging conditions and geometries, this work exploits a computational fluid dynamic model to investigate the effect of various design parameters on the performance of flow distributors in equally spreading the flow along the separation channels in the presence of different degrees of clogging. An array of radially elongated hexagonal pillars was selected for the separation channel (column). The design parameters include channel width, distributor width, aspect ratio of the pillars, and number of contact zone rows. The performance of known flow distributors, including bifurcating (BF), radially interconnected (RI), and recently introduced mixed-mode (MMI) in addition to two new distributors designed in this work (MMII and MMIII) were investigated in terms of mean elution time, volumetric variance, asymmetry factors, and pressure drop between the inlet and the monitor line for each design. The results show that except for pressure drop, the channel width and aspect ratio of the pillars has no significant influence on flow distribution pattern in non-clogged distributors. However, the behavior of flow distributors in response to clogging was found to be dependent on width of the channels. Also increasing the distributor width and number of contact zone rows after the first splitting stage showed no improvement in the ability to alleviate the clogging. MMI distributor with the channel width of 3 µm, aspect ratio of the pillars equal to 20, number of exits of 8, and number of contact zones of 3 exhibited the highest stability and minimum sensitivity to different degrees of clogging.

Theoretical Investigation of a Peristaltic Magneto-Fluid Dynamic Induction Compressor-2

1965 ◽  
Vol 9 (02) ◽  
pp. 56-65
Author(s):  
Joseph L. Neuringer ◽  
Eugene Migotsky ◽  
James H. Turner ◽  
Robert M. Haag
Keyword(s):  
Scaling Laws ◽  
Electromechanical Coupling ◽  
Constant Pressure ◽  
Fluid Dynamic ◽  
Pressure Rise ◽  
Magnetic Reynolds Number ◽  
Design Parameters ◽  
Propulsion Systems ◽  
Geometric Scaling ◽  
Axial Mass

In Part 3, the nature of the electromechanically induced motions inside the compressor both of the fluid conductor and of the pumped fluid when the electromechanical coupling is weak, i.e., in the limit of small magnetic Reynolds number, is investigated. The analysis predicts the development of a constant pressure gradient in the pumped fluid when the condition is imposed that the time-average axial mass flow across the conducting fluid annulus is zero. In Part 4, a preliminary feasibility study is made to determine whether the induction compressor has the potential to provide the pressure rise required to propel large and small undersea craft by means of jet propulsion systems for reasonable power and current-sheet inputs. Also determined here are the geometric scaling laws for the appropriate operating and design parameters.

Direct Liquid Cooling of High Flux LED Systems: Hot Spot Abatement

2013 ◽  
Author(s):  
Enes Tamdogan ◽  
Mehmet Arik ◽  
M. Baris Dogruoz
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Heat Removal ◽  
Heat Fluxes ◽  
Light Extraction ◽  
Junction Temperature ◽  
System Level ◽  
Design Parameters ◽  
Liquid Cooling ◽  
Wide Range

With the recent advances in wide band gap device technology, solid-state lighting (SSL) has become favorable for many lighting applications due to energy savings, long life, green nature for environment, and exceptional color performance. Light emitting diodes (LED) as SSL devices have recently offered unique advantages for a wide range of commercial and residential applications. However, LED operation is strictly limited by temperature as its preferred chip junction temperature is below 100 °C. This is very similar to advanced electronics components with continuously increasing heat fluxes due to the expanding microprocessor power dissipation coupled with reduction in feature sizes. While in some of the applications standard cooling techniques cannot achieve an effective cooling performance due to physical limitations or poor heat transfer capabilities, development of novel cooling techniques is necessary. The emergence of LED hot spots has also turned attention to the cooling with dielectric liquids intimately in contact with the heat and photon dissipating surfaces, where elevated LED temperatures will adversely affect light extraction and reliability. In the interest of highly effective heat removal from LEDs with direct liquid cooling, the current paper starts with explaining the increasing thermal problems in electronics and also in lighting technologies followed by a brief overview of the state of the art for liquid cooling technologies. Then, attention will be turned into thermal consideration of approximately a 60W replacement LED light engine. A conjugate CFD model is deployed to determine local hot spots and to optimize the thermal resistance by varying multiple design parameters, boundary conditions, and the type of fluid. Detailed system level simulations also point out possible abatement techniques for local hot spots while keeping light extraction at maximum.

Numerical Investigation of Heat Transfer of Twelve Plastic Leaded Chip Carrier (PLCC) by Using Computational Fluid Dynamic, FLUENTTM Software

2013 ◽  
Vol 795 ◽  
pp. 603-610 ◽  
Author(s):  
Mohamed Mazlan ◽  
A. Rahim ◽  
M.A. Iqbal ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
W. Razak ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Circuit Board ◽  
Junction Temperature ◽  
Inlet Velocity ◽  
Chip Carrier ◽  
Flow Through ◽  
Package Density ◽  
Heat And Fluid Flow

Plastic Leaded Chip Carrier (PLCC) package has been emerged a promising option to tackle the thermal management issue of micro-electronic devices. In the present study, three dimensional numerical analysis of heat and fluid flow through PLCC packages oriented in-line and mounted horizontally on a printed circuit board, is carried out using a commercial CFD code, FLUENTTM. The simulation is performed for 12 PLCC under different inlet velocities and chip powers. The contours of average junction temperatures are obtained for each package under different conditions. It is observed that the junction temperature of the packages decreases with increase in inlet velocity and increases with chip power. Moreover, the increase in package density significantly contributed to rise in temperature of chips. Thus the present simulation demonstrates that the chip density (the number of packages mounted on a given area), chip power and the coolant inlet velocity are strongly interconnected; hence their appropriate choice would be crucial.

Gas Purging System to Extend Thrust Bearing Life in ESPs

2021 ◽  
Author(s):  
Jose Caridad ◽  
Arthur Watson ◽  
Song Shang ◽  
Eric Nguyen ◽  
Gocha Chochua
Keyword(s):  
Thrust Bearing ◽  
Operating Conditions ◽  
Design Parameters ◽  
Motor Oil ◽  
Oil Viscosity ◽  
Test Fixture ◽  
Thrust Bearings ◽  
Working Volume ◽  
Gas Purging ◽  
Critical Components

Abstract Electric submersible pump (ESP) systems use thrust bearings in the seal section to handle the thrust generated by the pump stages. Thrust bearings are subjected to harsh operating conditions, including high loads, poor oil circulation, and motor oil viscosity degradation. A less-recognized issue is gas becoming centrifugally trapped under the thrust runner. The gas may be present because of incomplete purging of air during filling, permeation of well gas into the motor oil, or gradual gasification of motor oil at high temperatures. Because thrust bearings are such critical components, it is of interest to increase their reliability, which in turn will increase ESP life. A novel gas purging system (GPS) was designed to alleviate stressors on thrust bearings, including gas accumulation, viscosity deterioration and gasification at high temperature, and low working oil volume. GPS circulates oil along with any gas that accumulates under the thrust runner up to a quiet separation chamber. Degassed oil circulates back to the thrust bearing, while accumulated gas eventually purges to the wellbore through relief valves on subsequent on/off cycles. GPS also improves viscosity and reduces gasification by cooling the oil, and it provides a greater working volume of thrust bearing oil to reduce the effects of oil deterioration. This paper details the GPS design principles as well as the optimization of the different design parameters that affect its performance conducted via computational fluid dynamics (CFD). Observations captured on a test fixture built using the final configuration are also presented, validating the intended functionality.

scholarly journals Steady state analysis of regular hollow pyramidal radiating fin with triangular cross-section

2015 ◽  
Vol 19 (1) ◽  
pp. 59-68
Author(s):  
Vijaikrishnan Venkataramanan ◽  
Ramakrishnan Madhavaneswaran ◽  
Siva Shanmugam
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Cross Section ◽  
Working Conditions ◽  
Unit Mass ◽  
Design Parameters ◽  
Steady State Analysis ◽  
Fin Efficiency ◽  
Triangular Cross Section ◽  
Optimum Parameters

A new configuration for space radiator is proposed introducing a fin of regular hollow pyramidal shape with triangular cross section, giving a higher improvement in heat loss per unit mass than that of other corresponding configurations previously proposed under same working conditions. The significance of the present configuration and its advantage over other regular hollow configurations are discussed and effect of various design parameters on heat transfer is analyzed in presence of radiation interaction with an isothermal base attached to it. Optimum parameters are identified for which improvement in heat loss per unit mass is the maximum. It is found that the fin efficiency decreases with increase in the emissivity & height of the fin and increases with increase in thickness & top radius of the fin. Correlations are presented for optimum design parameters, optimum improvement in heat loss per unit mass and fin efficiency.

CFD Modeling of a Catalytic Flat Plate Fuel Reformer for Hydrogen Generation

2010 ◽  
Author(s):  
Kranthi K. Gadde ◽  
Panini K. Kolavennu ◽  
Susanta K. Das ◽  
K. J. Berry
Keyword(s):  
Flat Plate ◽  
Catalytic Combustion ◽  
Reaction Rates ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Design Parameters ◽  
Practical Implementation ◽  
Channel Height ◽  
Inlet Temperature ◽  
Two Dimensional

In this study, steam reforming of methane coupled with methane catalytic combustion in a catalytic plate reactor is studied using a two-dimensional mathematical model for co-current flow arrangement. A two-dimensional approach makes the model more realistic by increasing its capability to capture the effect of parameters such as catalyst thickness, reaction rates, inlet temperature and velocity, and channel height, and eliminates the uncertainties introduced by heat and mass transfer coefficients used in one-dimensional models. In our work, we simulate the entire flat plate reformer (both reforming side and combustion side) and carry out parametric studies related to channel height, inlet velocities, and catalyst layer thickness that can provide guidance for the practical implementation of such design. The operating conditions chosen make possible a comparison of the catalytic plate reactor and catalytic combustion analysis with the conventional steam reformer. The CFD results obtained in this study will be very helpful to understand the optimization of design parameters to build a first generation prototype.

CFD Modeling of Thermal Management Systems for a Silicon Semiconductor Switch

2020 ◽  
Author(s):  
Jordan N. Berg ◽  
Sarvenaz Sobhansarbandi
Keyword(s):  
Thermal Management ◽  
Fluid Dynamic ◽  
Jet Impingement ◽  
Liquid System ◽  
Pulse Power ◽  
Cfd Modeling ◽  
Inlet Temperature ◽  
Ansys Fluent ◽  
Term Operation ◽  
Semiconductor Switches

Abstract Silicon semiconductor switches are suitable for pulse power applications. When utilized in these applications, the switch receives a significant amount of power (i.e., heat) that is to be dissipated, which can result in the degradation of the switch. In order to maintain the functionality of the switch, a thermal management system (TMS) needs to be developed to keep the switch temperature at no higher than 80 °C during operation. This threshold is set due to an increase in electrical resistivity of silicon with an increase in temperature. This study compares the viability of two TMS, a microchannel and a jet impingement single-phase liquid system, to facilitate the long term operation of the switch for pulse power applications through performing computational fluid dynamic modeling (CFD) in ANSYS Fluent. The results from this study show that by utilizing a jet impingement system as TMS, the temperature of switch is maintained below the desired operating temperature when compared to that of the microchannel design under identical operating parameters (i.e., mass flow rate, coolant type and inlet temperature). Moreover, a cross validation of the thermal performance of the proposed systems has been made to further validate the obtained results.

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