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.

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 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.

Simulate Design of Direct Air Cooling Exhausted Duct System for 1000MW Super-Critical Thermal Power Unit

2014 ◽  
Vol 535 ◽  
pp. 180-184
Author(s):  
Chun Qing Wang ◽  
Cai Xia Bian ◽  
Di Wang
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Power Unit ◽  
Flow Resistance ◽  
Thermal Power ◽  
Flow Distribution ◽  
Cooling Power ◽  
Air Cooling ◽  
Exhaust Pipe ◽  
Balanced Flow

Balancing flow distribution and decreasing the pressure drop in each vapor distributing pipe are the importance of the study of exhaust pipe of direct air cooling power unit.In order to balance flow distribution and decreasing the pressure drop in each vapor distributing pipe,and simulate the flow field when add different chamfer on the back of exhausted pipe or not ,then using the CFD software called FLUENT,the steam flow field of exhausted pipe for a 1000 MW power unit with direct air cooling is stimulated under typical steam turbine conditions.The result shows that the steam flows through each distribution pipe with balanced flow under the condition of chamfer angle of 30 °and the flow resistance is much lower than before．

Thermal Design of Heat Exchanger With Fins Inside and Outside Tubes

2006 ◽  
Author(s):  
G. N. Xie ◽  
Q. Y. Chen ◽  
M. Zeng ◽  
Q. W. Wang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Total Pressure ◽  
Thermal Design ◽  
Operating Pressure ◽  
Heat Transfer Area ◽  
Tube Heat Exchanger ◽  
Total Pressure Drop

Compact heat exchangers such as tube-fin types and plate-fin types are widely used for gas-liquid or gas-gas applications. Some examples are air-coolers, fan coils, regenerators and recuperators in micro-turbines. In this study, thermal design of fin-and-tube (tube-fin) heat exchanger performance with fins being employed outside and inside tubes was presented, with which designed plate-fin heat exchanger was compared. These designs were performed under identical mass flow rate, inlet temperature and operating pressure on each side for recuperator in 100kW microturbine as well as specified allowable fractions of total pressure drop by means of Log-Mean Temperature Difference (LMTD) method. Heat transfer areas, volumes and weights of designed heat exchangers were evaluated. It is shown that, under identical heat duty, fin-and-tube heat exchanger requires 1.8 times larger heat transfer area outside tubes and volume, 0.6 times smaller heat transfer area inside tubes than plate-fin heat exchanger. Under identical total pressure drop, fin-and-tube heat exchanger requires about 5 times larger volume and heat transfer area in gas-side, 1.6 times larger heat transfer area in air-side than plate-fin heat exchanger. Total weight of fin-and-tube heat exchanger is about 2.7 times higher than plate-fin heat exchanger, however, the heat transfer rate of fin-and-tube heat exchanger is about 1.4 times larger than that of plate-fin heat exchanger. It is indicated that, both-sides finned tube heat exchanger may be used in engineering application where the total pressure drop is severe to a small fraction and the operating pressure is high, and may be adopted for recuperator in microturbine.

Two-Phase Pressure Drop Prediction in Wet Gas Flow Through V-Cone Meter

2014 ◽  
Author(s):  
Denghui He ◽  
Bofeng Bai
Keyword(s):  
Pressure Drop ◽  
Relative Error ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Flow ◽  
Equivalent Diameter ◽  
Operating Pressure ◽  
Two Phase ◽  
Wet Gas ◽  
Phase Pressure

The pressure drop is considerably significant for the differential pressure meter to measure the flow rate of the two-phase flow. Little is known about the pressure drop characteristics of the V-Cone meter when it is used to measure the wet gas flow. The objective of this paper is to investigate the two-phase pressure drop of the V-Cone meter and develop a correlation for predicting its pressure drop. A V-Cone meter with the equivalent diameter ratio of 0.55 was investigated experimentally. The experimental fluid was air and water. The test pressure ranged from 0.1 MPa to 0.4 MPa, and the gas and liquid mass flow rate ranged from 100 Nm3/h to 500 Nm3/h and from 0.05 m3/h to 2.2 m3/h, respectively. The experimental results showed that the existing correlations, which are developed for the orifice plate meter and the Venturi meter, are not applicable for the V-Cone meter to predict the pressure drop. The two-phase mass flow coefficient, K, was used to develop the two-phase pressure drop correlation. The influences of the Lockhart-Martinelli parameter, the gas densiometric Froude number and the operating pressure on K were investigated. The new pressure drop correlation can accurately predict the pressure drop of the V-Cone meter for the wet gas. The relative error of the pressure drop is less than ± 9.0% at the 95.1% confidence level and the average relative error is 3.88%. The pressure drop prediction correlation provides a reference for developing the correlation of the wet gas measurement.

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.

Analysis of the effects of pressure profile, furnish, and microfibrillated cellulose on the dewatering of papermaking furnishes

TAPPI Journal ◽  
2015 ◽  
Vol 14 (5) ◽  
pp. 325-337 ◽  
Author(s):  
ANTTI KOPONEN ◽  
SANNA HAAVISTO ◽  
JOHANNA LIUKKONEN ◽  
JUHA SALMELA
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Flow Resistance ◽  
Pressure Profile ◽  
Pilot Scale ◽  
Microfibrillated Cellulose ◽  
Laboratory Scale ◽  
Filtration Process ◽  
Furnish Type ◽  
Solids Content

In this paper, we present an improved experimental method for studying the initial dewatering process in papermaking. We studied the effects of the dewatering pressure profile, the furnish type, and microfibrillated cellulose (MFC) on the development of flow resistance and the final solids content of the filtered sheet. The major difference from the previous studies is the possibility to control the dewatering pressure profile during filtration. The filtration process is monitored by measuring the pressure drop over the filtrated sheet and the flow rate through the filtered sheet as a function of time. In the end, the final solids content is measured. Our results indicate that the sheet solids content after the initial dewatering depends on the magnitude and the shape of the pressure profile used during the filtration and that this dependency remains after wet pressing. Laboratory scale measurements are repeated in pilot scale using a papermaking research environment, with comparable results. Surprisingly, we found that the addition of MFC increases the solids content. This was verified in laboratory and pilot scale studies. Overall, this study shows that laboratory scale measurements can be useful in determining the optimal dewatering conditions for different furnish types.

Thermal Design of a Sealed Air Cooling Local Environment Control System for Precision Instruments In-Vehicle

2011 ◽  
Vol 120 ◽  
pp. 258-262
Author(s):  
Hong Cai Li ◽  
Fei Fan Chen ◽  
Yong Gui Dong
Keyword(s):  
Control System ◽  
Flow Rate ◽  
Local Environment ◽  
Thermal Design ◽  
Heat Transfer Analysis ◽  
Heat Radiation ◽  
Air Cooling ◽  
Heat Flow Rate ◽  
Electrical Analogy ◽  
Environment Control

Local environment control system (LECS) has been widely used in many areas as the necessary guarantee for most precision instruments. A sealed air cooling constant temperature box with dual-chamber structure that can provide constant working condition for precision instruments in-vehicle was developed. According to the heat transfer analysis of the double plate-fins heatsink, the heat radiation area and dimensions were determined based on electrical analogy. The air flow rate and temperature distribution of the system in heat steady-state was simulated by CFD software, and the results are consistent with that of experimental test. In different conditions, the thermal test results indicate that when the heat flow rate in the inner chamber is about 170 W, the temperature difference between inner chamber and environment is no more than 6.5 °C. The thermal design and test methods can be as the reference for the design of other precision instruments in-vehicle.

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