Dynamic Reduced Electrothermal Model for Integrated Power Electronics Modules (IPEM)

2004 ◽  
Vol 126 (4) ◽  
pp. 477-490 ◽  
Author(s):  
M. Herna´ndez-Mora ◽  
J. E. Gonza´lez ◽  
M. Ve´lez-Reyes ◽  
J. M. Ortiz-Rodrı´guez ◽  
Y. Pang ◽  
...  
Keyword(s):  
Power Electronics ◽  
Thermal Model ◽  
High Speed ◽  
Three Dimensional ◽  
Thermal Response ◽  
Software Tool ◽  
Computational Time ◽  
Highly Nonlinear ◽  
Numerical Formulation ◽  
Good Agreement

Background: This paper presents a reduced mathematical model using a practical numerical formulation of the thermal behavior of an integrated power electronics module (IPEM). This model is based on the expanded lumped thermal capacitance method (LTCM), in which the number of variables involved in the analysis of heat transfer is reduced only to time. Method of Approach: By applying the LTCM, a simple, nonspatial, but highly nonlinear model is obtained for the case of the IPEM Generation II. Steady and transient results of the model are validated against results from a three-dimensional, transient thermal analysis software tool, FLOTHERM™ 3.1. The electrothermal coupling was obtained by implementing the reduced-order thermal model into the SABER™ circuit simulator. Two experimental setups, for low- and high-speed thermal responses, were developed and used to calibrate the reduced model with actual data. Results: The comparison of the LTCM model implemented in a Generation II IPEM with FLOTHERM 3.1 results compared very favorably in terms of accuracy and efficiency, reducing the computational time significantly. Additional validations of the reduced thermal model were made using experiment data for the low-speed thermal response at different constant powers, and good agreement was demonstrated in all cases. A comparison between SABER™ simulations, which incorporated the proposed LTCM, and the fast thermal experimental response results is also presented to validate the dynamic electrothermal model response, and excellent agreement was found for this case. Conclusions: The good agreement found for all three cases presented, the three-dimensional, transient numerical formulation, and the low- and high-speed experimental data indicates that reduced electrothermal models are an excellent alterative for design methodologies of new generations of IPEMs.

scholarly journals Simulation of Thermal and Electric Field Distribution in Packaged Sausages Heated in a Stationary Versus a Rotating Microwave Oven

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1622
Author(s):  
Wipawee Tepnatim ◽  
Witchuda Daud ◽  
Pitiya Kamonpatana
Keyword(s):  
Temperature Distribution ◽  
Electric Field ◽  
Three Dimensional ◽  
Development Stage ◽  
Microwave Oven ◽  
Computational Time ◽  
Plastic Package ◽  
Heating Uniformity ◽  
The Cost ◽  
Good Agreement

The microwave oven has become a standard appliance to reheat or cook meals in households and convenience stores. However, the main problem of microwave heating is the non-uniform temperature distribution, which may affect food quality and health safety. A three-dimensional mathematical model was developed to simulate the temperature distribution of four ready-to-eat sausages in a plastic package in a stationary versus a rotating microwave oven, and the model was validated experimentally. COMSOL software was applied to predict sausage temperatures at different orientations for the stationary microwave model, whereas COMSOL and COMSOL in combination with MATLAB software were used for a rotating microwave model. A sausage orientation at 135° with the waveguide was similar to that using the rotating microwave model regarding uniform thermal and electric field distributions. Both rotating models provided good agreement between the predicted and actual values and had greater precision than the stationary model. In addition, the computational time using COMSOL in combination with MATLAB was reduced by 60% compared to COMSOL alone. Consequently, the models could assist food producers and associations in designing packaging materials to prevent leakage of the packaging compound, developing new products and applications to improve product heating uniformity, and reducing the cost and time of the research and development stage.

Three-Dimensional Creep Analysis of Solder Joints in Surface Mount Devices

1995 ◽  
Vol 117 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Pardeep K. Bhatti ◽  
Klaus Gschwend ◽  
Abel Y. Kwang ◽  
Ahmer R. Syed
Keyword(s):  
High Performance ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Nonlinear Material ◽  
Computational Time ◽  
Nonlinear Creep ◽  
Element Analysis ◽  
Surface Mount ◽  
Creep Analysis ◽  
Highly Nonlinear

Three-dimensional finite element analysis has been applied for determining time-dependent solder joint response of leaded surface mount components under thermal cycling. Two main challenges are the geometric complexity in mesh development and computationally intensive analysis because of the highly nonlinear material properties. Advanced techniques have been applied, including multi-point constraints for mesh transition, which reduces the number of degrees of freedom in the model, and substructuring, which effectively reduces computational time in the iterative analysis. The result is a generic approach for nonlinear creep analysis using commercial FEA software on a high performance workstation. Illustrations are provided for J and gullwing leaded packages.

Dynamic Reduced Electrothermal Model for Integrated Power Electronics Modules (IPEM): Part I — Thermal Analysis

2003 ◽  
Author(s):  
M. Herna´ndez-Mora ◽  
J. E. Gonza´lez ◽  
M. Ve´lez-Reyes ◽  
J. M. Orti´z ◽  
Y. Pang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Power Electronics ◽  
Software Tool ◽  
Electrical Performance ◽  
Reduced Model ◽  
Analysis Software ◽  
Thermal Capacitance ◽  
Capacitance Method ◽  
Numerical Formulation

This paper presents a reduced mathematical model using a practical numerical formulation of the thermal behavior of Integrated Power Electronics Modules (IPEM). This model is based on the expanded Lumped Thermal Capacitance Method (LTCM), in which the number of variables involved in the analysis of heat transfer is reduced to only time. Applying this procedure a simple, non-spatial, but highly non-linear model is obtained. Steady and transient results of the model are validated against results from a thermal analysis software tool, FLOTHERM 3.1™. A comparison between thermal results obtained with the reduced model and experimental data is presented indicating a need for incorporating the dynamic electrical performance in the reduced model. The development of this model presents an alternative to reduce the complexity level developed in commercial multidimensional and transient software for power electronics applications.

Reliability of SnAgCu Alloys for CMOS Image Sensor QFN Package under Thermal Cycling Loading

2008 ◽  
Vol 594 ◽  
pp. 175-180
Author(s):  
Hsiang Chen Hsu ◽  
Hui Yu Lee ◽  
Wen Lo Shieh
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Element Model ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Computational Time ◽  
Mesh Density ◽  
Good Agreement

A three-dimensional finite element model of CMOS image sensor QFN packaging using ANSYS codes is developed to investigate the solder joint reliability under thermal cycle test. The predicted thermal-induced displacements were found to be very good agreement with the Moiré interferometer experimental in-plane deformations. The developed finite element model is then applied to predict fatigue life of Sn4.0Ag0.5Cu, Sn3.5Ag0.5Cu and Sn3.9Ag0.6Cu alloys based on JEDEC standard JESD22-A104. In order to save computational time and produce satisfactory results in the region of interest, an independent more finely meshed so-called submodel scheme based on cut-boundary displacement method is generated. The mesh density for different area ratio of refinery/coarse model was verified and the results were found to be good agreement with previous researches. The modified Coffin-Manson equation and strain energy density based equation are applied to evaluate the reliability of SnAgCu alloys. A series of comprehensive parametric studies were conducted in this paper.

Experimental and numerical analyses of wedge effects on the rooster tail and porpoising phenomenon of a high-speed planing craft in calm water

2019 ◽  
Vol 233 (13) ◽  
pp. 4637-4652 ◽  
Author(s):  
Sayyed Mahdi Sajedi ◽  
Parviz Ghadimi ◽  
Mohammad Sheikholeslami ◽  
Mohammad A Ghassemi
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Scale Model ◽  
Test Cases ◽  
Planing Craft ◽  
Calm Water ◽  
Space Discretization ◽  
Good Agreement

This paper presents experimental and numerical investigation of stability and rooster tail of a mono-hull high-speed planing craft with a constant deadrise angle. Initially, a one-fifth scale model was tested in a towing tank, which showed porpoising phenomenon at 8 m/s (equal to the speed of sailing). Subsequently, two wedges of 5 and 10 mm heights, based on the boundary layer calculations, were mounted on the aft section of the planing hull. These wedges were shown to increase the lift at the aft section. These experiments were carried out at different speeds up to 10 m/s in calm water. The experimental results indicated that the installed wedges reduced the trim, drag, and the elapsed time for reaching the hump peak, and also eliminated the porpoising condition. All these test cases were also numerically simulated using Star CCM+ software. The free surface was modeled using the volume of fluid scheme in three-dimensional space. The examined planing craft had two degrees of freedom, and overset mesh technique was used for space discretization. The obtained numerical results were compared with experimental data and good agreement was displayed in the presented comparisons. Ultimately, the effect of the wedge on the rooster tail behind the planing craft was studied. The results of this investigation showed that by decreasing the trim at a constant speed, the height of the generated wake profile (rooster tail) behind the craft decreases, albeit its length increases.

Study of Steady State and Transient Blade Row CFD Methods in a Moderately Loaded NASA Transonic High-Speed Axial Compressor Stage

2013 ◽  
Author(s):  
Mohammed Abdullah Qizar ◽  
Mahmoud L. Mansour ◽  
Shraman Goswami
Keyword(s):  
Steady State ◽  
High Speed ◽  
Transient Flow ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Computational Time ◽  
Laser Doppler Velocimeter ◽  
Compressor Stage ◽  
Steady Stage ◽  
Blade Row

The effect of blade row interaction and hub leakage flow on the performance of moderately loaded NASA transonic hybrid compressor stage (Rotor 35 / Stator 37) is investigated through three-dimensional steady state and time-accurate, Navier Stokes calculations of the stage using the ANSYS CFX code at peak efficiency and near stall operating conditions. Understanding unsteady flow phenomena in compressor stages requires the use of time-accurate CFD simulations. Due to the inherent differences in blade counts between adjacent blade rows, the flow conditions at any given instant in adjacent blade rows differ. Depending on the blade counts, it may be necessary to model the entire annulus of the stage; however, this requires considerable computational time and memory resources. Several methods for modeling the transient flow in turbo machinery stages which require a minimal number of blade passages per row, and therefore reduced computational demands, have been presented in the literature. Recently, some of these methods have become available in commercial CFD solvers. The paper describes the steady and the unsteady CFD approaches used for investigating the ability to predict the measured performance of the NASA transonic axial stage design known as the hybrid stage, which consists of the axial Rotor35 and the axial stator 37. The steady approach employs the mixing-plane while the unsteady approaches are URANS with one based on full annulus simulation for the stage and the second enables simulations for the stage using reduced computational model, with a single passage from each blade row based on the time-tilting or the time-transformation technique. The above methods are evaluated and compared in terms of computational efficiency and comparison is made to steady stage simulations. Comparisons to overall performance data and two-dimensional Laser Doppler Velocimeter measurements of the velocity field are used to assess the predictive capabilities of the methods. Computed flow features are examined, and compared with reported measurements. This paper presents validation and calibration of methods used for determining blade row interactions and the respective predictive capabilities against the full annulus and the experimental test data.

scholarly journals Shrink-fitted joint behavior using three-dimensional solid finite elements in rotor dynamics with inclusion of stress-stiffening effect

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401878005 ◽  
Author(s):  
Eerik Sikanen ◽  
Janne E Heikkinen ◽  
Jussi Sopanen
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Three Dimensional ◽  
Campbell Diagram ◽  
Finite Element Software ◽  
Element Approach ◽  
Solid Finite Elements ◽  
Rotor Assembly ◽  
Stiffening Effect ◽  
Good Agreement

In this article, the contact behavior of a shrink-fitted joint in a rotor assembly at different spin speeds is studied, using the three-dimensional solid finite element approach. A custom frictionless contact model is proposed and extensively tested by means of simulation. The theory for solving pre-stressed damped eigenvalue problem is presented and implemented, and the results are presented in Campbell diagram form. Two sample rotor assemblies are studied. In addition, experimental modal analysis results of a shrink-fitted joint with various interferences are presented and numerically studied. The reduction of the interference of the shrink-fitted joint due to centrifugal forces at high-speed operation as well as the contact status are updated at each rotational speed step. The inclusion of stress-stiffening effect is studied in detail. The comparison of the Campbell diagram results with the results obtained using a commercial finite element software (Ansys) shows a good agreement.

Predictive Simulation of Underwater Implosion: Coupling Multi-Material Compressible Fluids With Cracking Structures

2014 ◽  
Author(s):  
Kevin G. Wang ◽  
Patrick Lea ◽  
Alex Main ◽  
Owen McGarity ◽  
Charbel Farhat
Keyword(s):  
Structural Dynamics ◽  
High Speed ◽  
Three Dimensional ◽  
Computational Approach ◽  
Quantitative Prediction ◽  
Potential Threat ◽  
Two Phase ◽  
Riemann Solvers ◽  
Adjacent Structures ◽  
Highly Nonlinear

The implosive collapse of a gas-filled underwater structure can lead to strong pressure pulses and high-speed fragments that form a potential threat to adjacent structures. In this work, a high-fidelity, fluid-structure coupled computational approach is developed to simulate such an event. It allows quantitative prediction of the dynamics of acoustic and shock waves in water and the initiation and propagation of cracks in the structure. This computational approach features an extended finite element method (XFEM) for the highly-nonlinear structural dynamics characterized by large plastic deformation and fracture. It also features a finite volume method with exact two-phase Riemann solvers (FIVER) for the solution of the multi-material flow problem arising from the contact of gas and water after the structure fractures. The Eulerian computational fluid dynamics (CFD) solver and the Lagrangian computational structural dynamics (CSD) solver are coupled by means of an embedded boundary method of second-order accuracy in space. The capabilities and performance of this computational approach are explored and discussed in the full-scale simulations of a laboratory implosion experiment with hydrostatic loading and a three-dimensional manufactured implosion problem with explosion loading.

Vertical Wedge Water-Entry through Experiments and Simulation to Explore Three-Dimensional Hydrodynamic Flow Characteristic

2021 ◽  
Author(s):  
Arman Bhardwaj ◽  
M. Javad Javaherian ◽  
Nicholas Husser
Keyword(s):  
High Speed ◽  
Flow Characteristic ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Water Entry ◽  
Pressure Measurements ◽  
Comparison Of Experiments ◽  
Small Craft ◽  
3D Effects ◽  
Good Agreement

Slamming is a critical loading condition that governs design of high-speed small craft. Due to sparse pressure measurements in previously conducted experimental studies and uncertainties in numerical simulations, a combined study to fully understand the three-dimensional fluid-dynamics effects on the bottom of a wedge is presented herein. The focus of this paper is on a comparison of experiments and simulations on the water-entry of a rigid wedge that represents a transverse wedge cross section of a Generic Prismatic Planing Hull (GPPH). The results show that the simulations are in very good agreement with the experiments and that these 3D effects can accurately be modeled.

Interaction between two laser-induced cavitation bubbles in a quasi-two-dimensional geometry

2009 ◽  
Vol 633 ◽  
pp. 425-435 ◽  
Author(s):  
PEDRO A. QUINTO-SU ◽  
CLAUS-DIETER OHL
Keyword(s):  
Potential Flow ◽  
High Speed ◽  
Three Dimensional ◽  
Interaction Force ◽  
High Speed Photography ◽  
Two Dimensional ◽  
Experimental Conditions ◽  
Numerical Studies ◽  
Cavitation Bubbles ◽  
Good Agreement

We report on experimental and numerical studies of pairs of cavitation bubbles growing and collapsing close to each other in a narrow gap. The bubbles are generated with a pulsed and focused laser in a liquid-filled gap of 15 μm height; during their lifetime which is shorter than 14 μs they expand to a maximum radius of up to Rmax = 38 μm. Their motion is recorded with high-speed photography at up to 500000 frames s−1. The separation at which equally sized bubbles are created, d, is varied from d = 46–140 μm which results into a non-dimensional stand-off distance, γ = d/(2Rmax), from 0.65 to 2. For large separation the bubbles shrink almost radially symmetric; for smaller separation the bubbles repulse each other during expansion and during collapse move towards each other. At closer distances we find a flattening of the proximal bubbles walls. Interestingly, due to the short lifetime of the bubbles (≤14 μs), the radial and centroidal motion can be modelled successfully with a two-dimensional potential flow ansatz, i.e. neglecting viscosity. We derive the equations for arbitrary configurations of two-dimensional bubbles. The good agreement between model and experiments supports that the fluid dynamics is essentially a potential flow for the experimental conditions of this study. The interaction force (secondary Bjerknes force) is long ranged dropping off only with 1/d as compared to previously studied three-dimensional geometries where the force is proportional to 1/d2.

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