Takashi Fukue

Bio: Takashi Fukue is an academic researcher from Iwate University. The author has contributed to research in topics: Heat transfer enhancement & Airflow. The author has an hindex of 4, co-authored 26 publications receiving 55 citations.

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

Abstract: 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 fanCopyright © 2013 by ASME

Cooling performance of impinging jet from piezoelectric micro blower mounted in narrow flow passage

Abstract: This study investigates a cooling performance of a miniature piezoelectric micro blower. The piezoelectric micro blower is a novel airflow generator which combines a compact size which can be usable in a narrow clearance between the components with the high performance which can generate high speed airflow (about 20 m/s) regardless of a high pressure drop in the narrow clearance. We are investigating whether the piezoelectric micro blower is available for a novel cooling method of high-density packaging electronic equipment or not. Because of the miniature structure of the piezoelectric micro blower, a supply flow rate of the blower becomes relatively small. However, because the piezoelectric micro blower can generate the high speed airflow, the higher cooling performance than other micro fans may be obtained. Therefore, an investigation of a net cooling performance of the jet from the piezoelectric micro blower should be clarified. In this report, we tried to evaluate the cooling performance of an impinging jet from the piezoelectric micro blower by using 3DCFD (Computational Fluid Dynamics) analysis. The piezoelectric micro blower was mounted in front of test heat sinks and generated the impinging jet. The cooling performance of the heat sink with the impinging jet from the piezoelectric micro blower was evaluated while changing dimensions of the heat sink. Through the investigation, information about the optimum dimensions and types of the heat sink for improving cooling performance of the piezoelectric micro blower was obtained.

Basic study on flow and heat transfer performance of pulsating air flow for application to electronics cooling

Abstract: Our study tries to apply a pulsating airflow to one of a heat transfer enhancement method in electronic equipment. In recent electronic equipment, a lot of electrical components are mounted while their performance increases and a level of heat dissipation becomes higher. The components cause flow separation of the cooling air and heat transfer performance rear the components generally decreases. Therefore the mounting position of the heating components is restricted in order to avoid the separated flow region. In order to improve the heat transfer rear the components, we are now focusing on the flow pulsation. By generating the flow pulsation of the airflow, the development of the separated flow region rear the components may be inhibited and the heat transfer performance rear the components may be improved. In addition, the flow pulsation can be generated by controlling the input power of the cooling fan easily. From these backgrounds, we tried to investigate flow and heat transfer characteristics of the pulsation flow around the components. In this report, we developed the experimental system in order to evaluate flow and heat transfer performance of the pulsation flow around the electrical components experimentally. By using the experimental system, we tried to evaluate the cooling performance of the pulsation flow around cylindrical blocks, which simulates electrical components. Through the experiment, we evaluated the effectiveness of the pulsation flow as the cooling method of electronic equipment.

Evaluation of cooling performance of a piezoelectric micro blower in narrow flow passage

Abstract: This paper describes a cooling performance of a novel miniature piezoelectric micro blower. We especially focus on an investigation whether the piezoelectric micro blower is available for a novel cooling method of high-density packaging electronic equipment or not. In order to investigate the effectiveness of the piezoelectric micro blower, an understanding of the blower performance (P - Q curve) becomes important. Especially, the effects of narrow flow passages and components around the blower on the P - Q curve should be investigated in order to apply the blower to high-density packaging electronic equipment. In addition, because of the miniature structure of the piezoelectric micro blower, a supply flow rate of the blower becomes relatively small. Therefore, an estimation of a net cooling performance of the piezoelectric micro blower should be investigated. In this paper, we evaluated a cooling performance of the piezoelectric micro blower. We firstly evaluated the P - Q curve of the piezoelectric micro blower. Especially the effects of the electrical components mounted near the blower on the P - Q curve. It is found that the performance characteristic of the proposed blower is almost not changed regardless of the existence of the components near the blower. In addition, we secondly investigated the cooling performance of the proposed blower in a narrow flow passage with finned heat sinks experimentally. Through the investigations, we evaluated the effectiveness of the piezoelectric micro blower as the cooling method of high-density packaging electronic equipment.

Effects of Clearance around Square Pillar in Rectangular Enclosure on Cooling Performance of Pulsating Airflow

Abstract: This study focuses on a development of heat transfer enhancement techniques using pulsating flow for thermal equipment such as electronic equipment and heat exchangers. In this report, the heat transfer performance of the pulsating airflow around the heating pillar mounted in the rectangular enclosure was investigated experimentally while changing the size of the clearance between the enclosure wall and the pillar. The pillar simulates the components mounted in thermal equipment such as fins and electrical components. The rectangular enclosure simulates an enclosure of electronic equipment and heat exchangers. The shape of the cross section of the pillar was square having sides 30 mm. The dimension of the width of the enclosure was changed from 50 mm to 80 mm. It was found that the heat transfer performance of the pulsating airflow became higher than that of the steady flow regardless of the dimension of the clearance. The heat transfer enhancement around heating components by the pulsating flow can be available regardless of the clearance around the components.

Heat Management in Power Converters: From State of the Art to Future Ultrahigh Efficiency Systems

Abstract: Thermal management is a key design aspect of power converters since it determines their reliability as well as their final performance and power density. Cooling technologies have been a research area in electronics since the 1940s and, in the last 15 years, the number of articles related to this field has grown significantly. At present, thermal management is essential in new disciplines and it is a critical enabling technology in the development of power electronic systems. This paper aims at presenting a review of the state-of-the-art technology and provides future design guidelines for high efficiency power electronic converters. The main design trends are focused on the need to develop cooling systems able to manage high local density heat fluxes due to two converging trends: higher power dissipation and smaller module size. Considering the latest advances in thermal management, as well as the huge improvement in power electronics in the last decades, a review and classification of the main thermal management techniques is presented. Besides, they are compared considering important parameters such as peak power dissipation, efficiency, cost/complexity, power density or technical maturity, and a design example for an ultrahigh efficiency converter is presented.