Experimental Study on Thermal Performance of a Forced Air Cooled PBGA Package in the Compact Thin Casing: Effect of Obstacles Placed Inside the Casing

Author(s):  
Masaru Ishizuka ◽  
Shinji Nakagawa ◽  
Katsuhiro Koizumi

At the PC design stage, heat flow analysis in a PC is needed. However, due to the complex printed wiring board structure, a large number of grids are required to enable precise calculation, ruling out calculations using a conventional PC. This has led to attempts to predict the temperature of an actual package by calculation based on a simplified package whose result is then modified. In this study, a compact casing and a package model are used to simulate actual notebook PCs. The performance of a diode package is experimentally obtained, and the flow inside the casing and the thermal performance of the package are studied with an obstacle placed inside the casing. This study is also conducted by aiming at acquisition of benchmark test data for CFD simulations.

Author(s):  
Yong Wang ◽  
Guang Yuan ◽  
Yong-Kyu Yoon ◽  
Mark G. Allen ◽  
Sue Ann Bidstrup

Thermal management of electronic systems is of increasing concern as densities and power consumption increase. Typical thermal management solutions are modular in nature; e.g., a heat sink and/or fan area added to a heat-producing part. In this work, an integrated solution, the active cooling substrate (ACS) is proposed, in which the cooling functionality is included in the printed wiring board alongside the electrical wiring. The mechanism for cooling is the use of synthetic jets embedded in the substrate. The utility of the active cooling substrate is demonstrated through quantitative measurements of thermal performance of instrumented platinum heater testbeds. Thermal management is enhanced through the additional heat convection mode introduced by the embedded synthetic jets in the active cooling substrate.


1999 ◽  
Author(s):  
Constantin A. Dinu ◽  
Donald E. Beasley

Abstract The common architecture of the fluid delivery devices employed in the horizontal processing of printed wiring boards, makes use of high velocity jets directed normally or at some angle towards the board which moves above rollers. Usually, a single slot jet or a linear arrays of jets are employed in order to increase the transport properties of the flow in the vicinity of the printed wiring board. In the present study, a geometry resembling a fluid delivery device used in printed wiring board manufacturing was investigated both experimentally and numerically. The printed wiring board is represented by an endless belt, which is transported horizontally by a system of rollers. The working fluid is delivered by an array of 13 square jets with a hydraulic diameter of 5.02 mm and a separation distance between jets of 4 hydraulic diameters. Two confinement plates located on each side of the jet array are used to confine the flow region and adjust the flow resistance at the two openings — between the rollers and the confinement plates — symmetrically located with respect to the centerline of the row of jets. The experimental setup and the numerical model both allowed the investigation of the effect of complex confinement (due to the board, confinement plates and rollers) and of the moving boundaries (impingement surface and rollers) on the characteristics of impinging flow. The flow field and the heat transfer characteristics were investigated for the jet Reynolds number ranging from 500 to 2000, non-dimensional impingement surface velocity ranging from 0 to 1 and non-dimensional impingement distance of 3 and 5. The CFD simulations were performed using the commercial CFD code PHOENICS. Flow visualization and particle image velocimetry were employed in order to experimentally investigate the flow field and validate the CFD simulations. The predicted results compare well with the observed jet behavior. A detailed description of the flow physics is presented. The numerical simulations show that for the same mass flow rate, the row of jets has a higher transport effectiveness when compared to a slot jet.


2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.


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