Flow Resistance Network Analysis in Fan-Cooled High-Density Packaging Electronic Equipment

2015 ◽  
Author(s):  
Takashi Fukue ◽  
Tomoyuki Hatakeyama ◽  
Masaru Ishizuka ◽  
Koichi Hirose ◽  
Kazuma Obata ◽  
...  
Keyword(s):  
Network Analysis ◽  
Flow Resistance ◽  
High Density ◽  
Thermal Design ◽  
Electronic Equipment ◽  
Test Model ◽  
Resistance Network ◽  
Electrical Components ◽  
Cooling Air ◽  
High Density Packaging

This study describes an application of the flow resistance network analysis to thermal design of fan-cooled electronic equipment. Especially, a modeling method of the flow resistance network was investigated. Current electronic equipment becomes smaller and thinner while their functions become more complex. As a result, flow passages for cooling air become complex. In order to simulate the complex airflow in high-density packaging electronic equipment by using the flow resistance network, we tried to develop the flow resistance network by support of the 3D-CFD analysis. A test model which simulates high-density packaging electronic equipment is prepared and the flow resistance network analysis is applied to the prediction of flow rate distribution in the model. Through the investigation, we obtained information and future problems about the development of the flow resistance network in electronic equipment with lots of electrical components.

Resistance Network Analysis of Airflow and Heat Transfer in a Thin Electronic Equipment Enclosure With a Localized Finned Heat Sink

2010 ◽  
Author(s):  
Takashi Fukue ◽  
Masaru Ishizuka ◽  
Shinji Nakagawa ◽  
Tomoyuki Hatakeyama ◽  
Wataru Nakayama
Keyword(s):  
Network Analysis ◽  
Thermal Performance ◽  
Heat Sink ◽  
Design Method ◽  
Electrical Equipment ◽  
Thermal Design ◽  
Electronic Equipment ◽  
Resistance Network ◽  
Fast Development ◽  
Analytical Accuracy

In recent years, thermal design of electrical equipment becomes importance and fast thermal design is required due to the fast development of electrical devices. We have proposed the flow and thermal resistance network analysis (coupled network analysis) as a fast thermal design method for electrical equipment. In this paper, we described analytical accuracy of the coupled network analysis of thin electronic equipment including the finned heat sink. We especially focused on the prediction of thermal performance on heatsink by using the coupled network analysis. For considering the accuracy of the coupled network analysis, we compared the results of the coupled network analysis with those of CFD analysis and the experiment. The results showed that the coupled network analysis can predict accurate thermal performance of heat sink and moreover accurate temperature distribution of electrical equipment.

Relationships Between Supply Flow Rate of Small Cooling Fans and Pressure Drop Characteristics in Electronic Enclosure

2013 ◽  
Author(s):  
Takashi Fukue ◽  
Tomoyuki Hatakeyama ◽  
Masaru Ishizuka ◽  
Koichi Hirose ◽  
Katsuhiro Koizumi
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Flow Resistance ◽  
High Density ◽  
Thermal Design ◽  
Air Cooling ◽  
Operating Pressure ◽  
Resistance Curve ◽  
Cooling Fans ◽  
High Density Packaging

This study describes a prediction method of a supply flow rate of axial cooling fans mounted in high-density packaging electronic equipment. The performance of an air-cooling fan is defined by its P – Q (pressure difference – flow rate) curve. Generally the operating point of a fan, which is the operating pressure and the flow rate in equipment, is the point of intersection of a P – Q curve and a flow resistance curve. Recently, some researchers reported that catalogue P – Q curves have not necessarily been able to predict a correct supply flow rate in thermal design of high-density packaging equipment. Our study aims to improve prediction accuracy of the supply flow rate. In this report, a relationship between the P – Q curve and a pressure drop characteristic in a fan-mounted enclosure was investigated. A test enclosure which includes an obstruction was mounted in front of a test fan and the supply flow rate of the fan was measured while changing the obstruction. Additionally the flow resistance curves in the test enclosure were measured and the relationship among the supply flow rate, the P – Q curve and the flow resistance curve was investigated. It is found that the correct supply flow rate can be obtained by using the flow resistance from the enclosure inlet through the fan outlet and the revised P – Q curve which is made compensation for the pressure drop at the inlet and the outlet of the fan.

Force Air Cooled Electronic Equipment Under Loss of Cooling Condition With Blocked Air Duct

2007 ◽  
Author(s):  
Frank Fan Wang
Keyword(s):  
Thermal Design ◽  
Electronic Equipment ◽  
Cooling Condition ◽  
Worst Case ◽  
Aerospace Applications ◽  
Air Inlet ◽  
Design Options ◽  
Forced Cooling ◽  
Cooling Air ◽  
Mean Time

There are many electronic equipments are cooled by forced cooling airs. Some equipment’s forced cooling air is supplied by air ducts, where air blower is located at a distance. In many cases, when the remote blower is out of order, the buoyancy of heated air cannot generate enough pressure to overcome the long air ducts and the blower. There is no air flow at all through the normal cooling air duct. That is called loss of cooling thermal condition. Loss of cooling condition is usually the worst case thermal challenge. In aerospace applications, most forced convection cooled electronic equipments need to meet the loss of cooling operation requirement. During loss of cooling, the electronic equipment needs to obtain cooler ambient surrounding air from a different inlet other than the supply air inlet. However, the passive cooling air inlet cannot interfere with the normal cooling situation. In normal cooling situation, forced cooling air is provided to lower the electronics temperature to a level of meeting the mean time between failure (MTBF) requirements. This paper will discuss a few trade studies of how different design approaches meet this loss of cooling air challenges; present a detailed CFD calculation of one of the design options. Many other considerations are also to be presented other than just thermal design concerns.

The effects of the outlet area and the location of the main power supply unit on the cooling capability through naturally air-cooled electronic equipment casings

1998 ◽  
Vol 212 (5) ◽  
pp. 381-383 ◽  
Author(s):  
M Ishizuka
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Power Supply ◽  
Flow Resistance ◽  
Thermal Design ◽  
Electronic Equipment ◽  
Power Supply Unit ◽  
Air Cooling ◽  
Uniform Temperature ◽  
Cooling Systems

This paper describes a practical thermal design approach to natural air-cooled electronic equipment casings. A set of simplified equations for the thermal design of natural air-cooled electronic equipment casings has been proposed. The proposed set of equations satisfied the demand of practical air-cooling systems, since it takes account of factors such as the stack effect, the air flow resistance and the heat transfer due to natural convection. The effects of the outlet area and the location of the main power supply unit on the natural cooling capability of electronic equipment casings were studied using a set of equations. The results have shown that a uniform temperature distribution could be achieved when the main power supply unit was placed at the bottom of the casing. It has also been suggested that the value of the heat removed from the casing surface could be more significant than that from the outlet vent in the thermal design of natural air-cooled electronic equipment casings.

Study on P-Q Curves of Cooling Fans for Thermal Design of Electronic Equipment (Effects of Opening Position of Obstructions Near a Fan)

2011 ◽  
Author(s):  
Takashi Fukue ◽  
Masaru Ishizuka ◽  
Tomoyuki Hatakeyama ◽  
Shinji Nakagawa ◽  
Katsuhiro Koizumi
Keyword(s):  
Flow Rate ◽  
Perforated Plate ◽  
Pressure Rise ◽  
High Density ◽  
Thermal Design ◽  
Electronic Equipment ◽  
Flow Passage ◽  
Fan Performance ◽  
Cooling Fan ◽  
Cooling Fans

This study describes an operation pressure and supplies flow rate of an axial cooling fan installed in high-density packaging electronic equipment. Fan performance is generally defined by their P-Q curve, specifically, a relationship between fan pressure rise (ΔP) and flow rate (Q). A compact cooling fan often operates in a high-density mounting device, which may decrease the fan performance. In this study, we focus on an obstruction near a fan, which is electronic components such as PCBs, capacitors and heat sinks, as one of a factor which decreases fan performance. We installed a perforated plate which simulated the above components near a fan and measured the P-Q curve. To investigate a relationship between a fan performance decrease and an opening position near the fan, a part of the perforated plate was closed. Closed position was changed and explored an opening condition which caused the dominant fan performance decrease. From experiments, it was found that the fan performance was decreased when flow passage in front of a fan was blocked by an obstruction. Especially, when flow passage in front of a fan hub was blocked, a dominantly reduction of fan pressure was caused. An obstruction rear a fan has no effect on a fan performance curve itself. In addition, opening conditions in front of a fan tip had a little influence on a fan pressure characteristic when there was no obstruction in front of a hub.

Flow and Thermal Resistance Network Modeling of Finned Heat Sinks With Bypass Mounted in Rectangular Enclosure

2021 ◽  
Author(s):  
Masaya Fukada ◽  
Takashi Fukue ◽  
Yasuhiro Sugimoto ◽  
Tomoyuki Hatakeyama ◽  
Masaru Ishizuka
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Thermal Design ◽  
Electronic Equipment ◽  
Heat Sinks ◽  
Rate Distribution ◽  
Resistance Network ◽  
Convection Cooling

Abstract This study describes a thermal design method of forced convection cooling in high-density packaging electronic equipment for upstream design processes by flow and thermal resistance network analysis. Forced convection cooling by combining fans and heat sinks is the most standard strategy for dissipating heat from electronic equipment. In recent years, the thermal design of electronic equipment becomes more critical, and fast thermal design is required due to the rapid development of final products. We have been developing the flow and thermal resistance network analysis as the quick thermal design method for electronic equipment. However, an accurate prediction of forced convection cooling performance by finned heat sinks mounted in high-density packaging electronic equipment is generally tricky. Some bypasses, which are clearances between the heat sinks and enclosure walls or other components, exist around the heat sinks. Therefore, a flow rate distribution between the heat sink fins and the bypasses should be predicted. Many researchers have investigated hydrodynamic characteristics and heat transfer characteristics of finned heat sinks. However, many previous studies have been conducted on the finned heat sink performance when there are no bypasses. In order to achieve an optimum design of the finned heat sinks in the upstream configuration regardless of the heat sink dimensions, a systematic database of hydrodynamic characteristics and heat transfer characteristics of the finned heat sinks with bypasses should be investigated. This paper discusses the development of function models of pressure drop, flow rate distribution, and heat transfer of the finned heat sinks with the bypasses for the resistance network analysis through experiments and CFD analysis. Several types of finned heat sinks with 40 mm in width and 80 mm in length were prepared, and these were mounted in a rectangular enclosure with 45 mm in width and height. First, the pressure drop characteristic around the heat sink was investigated. In addition, the flow rate distribution between the heat sink and the bypass was evaluated separately. A flow branching coefficient was developed to predict the flow rate distribution around the heat sink combined with the pressure drop coefficient. Using the developed flow branching coefficient, the flow and thermal resistance network model around the finned heat sink was developed. The results from the proposed resistance network model showed good agreement with those from the experiment.

CFD - Based Investigation of Effects of Obstruction in Front of Small Axial Cooling Fan and Deterioration of Supply Flow Rate

2021 ◽  
Author(s):  
Tetsushi Fukuda ◽  
Yukio Masuda ◽  
Takashi Fukue ◽  
Yasuhiro Sugimoto ◽  
Tomoyuki Hatakeyama ◽  
...  
Keyword(s):  
Flow Pattern ◽  
Flow Rate ◽  
Pressure Rise ◽  
Leading Edge ◽  
Rotating Stall ◽  
High Density ◽  
Electronic Equipment ◽  
Fan Performance ◽  
Cooling Fan ◽  
High Density Packaging

Abstract This study describes the deterioration of a small axial fan’s supply flow rate in high-density packaging electronic equipment. A cooling fan flow rate can be predicted by its P-Q curve, which shows a relationship between a pressure rise at a fan (ΔP) and a supply flow rate (Q). However, in high-density packaging electronic equipment, the fan performance is affected by the mounting components around the fans, and the accurate prediction of the supply flow rate becomes difficult. This paper tried to do flow visualization around a small axial cooling fan’s impellers when the obstruction was mounted in front of the fan through CFD analysis. A relationship between the supply flow rate by the fan and the flow pattern around the impellers was investigated while changing the distance between the test fan and the obstruction. Through this study, the following results can be obtained. The fan’s flow is stable in the rotating stall region and the higher flow rate operating points regardless of whether or without the obstruction. At the lower flow rate conditions, the formation of a complex unsteady flow is reproduced. As the flow rate decreases, the flow’s separation point becomes closer to the leading edge of the impeller. In the case of obstruction, the change of the flow pattern causes a larger attack angle. As a result, fan performance is degraded.

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