Local Hot Spots of Electric Water Pump Casing Over Various Pumping Loads

2020 ◽  
Author(s):  
Younghyeon Kim ◽  
Yoora Choi ◽  
Sangseok Yu
Keyword(s):  
Temperature Distribution ◽  
Joule Heating ◽  
Hot Spots ◽  
Cooling System ◽  
Hot Spot ◽  
Maximum Temperature ◽  
Water Pump ◽  
Ir Camera ◽  
Heat Rejection ◽  
Electric Water Pump

Abstract The cooling system of an electric vehicle adopts an electric water pump. Since the lifespan of the battery is very sensitive to a very narrow temperature band, the cooling system provides key solutions. The electric water pump is a core component of the cooling system which satisfies performance and durability criteria. Since, a local hot spot of motor casing results in the degradation of motor lifespan, it is necessary to design the motor casing for effective heat rejection. In this study, two different motor casing designs are applied to reject the joule heating of the motor efficiently. The temperature distribution of each casing is investigated with an IR camera. The IR camera was used to identify the local hot spot where the heat was most generated in the pump. Since the joule heating is proportional to pump power, it is necessary to understand the operating characteristics of the electric water pump. The experimental apparatus includes a water reservoir, a bypass valve, pressure and temperature sensors, DAQ, and IR camera. The operating temperature is ranged from atmospheric temperature to 50°C. When the pump is operated with 25°C coolant, each experiment takes 1 hour for the steady-state conditions and maximum temperature up to 55 °C. Three different pump performance are investigated with two different pump casing. The coolant temperature is also changed from 25 °C to 50 °C. As a result, the local hot spot is strongly dependent to pump load and it is mainly observed near the cable connector. Since temperature distribution on the casing surface is also affected by local hot spots, it is necessary to optimize heat rejection by extended surface.

scholarly journals Initiation of solid explosives by impact and friction: the influence of grit

1949 ◽  
Vol 198 (1054) ◽  
pp. 337-349 ◽  
Keyword(s):  
Melting Point ◽  
Hot Spots ◽  
Hot Spot ◽  
Threshold Value ◽  
Maximum Temperature ◽  
Melting Points ◽  
Solid Explosives ◽  
Lower Melting Point ◽  
Determining Factor ◽  
Spot Temperature

This paper describes an experimental study of the initiation of solid explosives, and in particular the effect of artificially introducing transient hot spots of known maximum temperature. This was done by adding small foreign particles (or grit) of known melting-point. The minimum transient hot-spot temperature for the initiation of a number of secondary and primary explosives has been determined in this way. It is shown that the melting-point of the grit is the determining factor , and all the grits which sensitize these explosives to initiation either by friction or impact have melting-points above a threshold value which lies between 400 and 550 ° C. Grit particles of lower melting-point do not sensitize the explosives. The same explosives initiated by the adiabatic compression of air required, for initiation, minimum transient temperatures of the same order as the threshold melting-point values. The results provide strong evidence that the initiation of solids as well as of liquids by friction and impact is thermal in origin and is due to the formation of localized hot spots. There is evidence that in the case of the majority of secondary explosives which melt at comparatively low temperatures, intergranular friction is not able to cause explosion and the hot spots must be formed in some other way. With the primary explosives which explode at temperatures below their melting-points, hot spots formed by intergranular friction can be important.

scholarly journals Effect of Loads on Temperature Distribution Characteristics of Oil-Immersed Transformer Winding

2021 ◽  
Author(s):  
Zhengang Zhao ◽  
Zhangnan Jiang ◽  
Yang Li ◽  
Chuan Li ◽  
Dacheng Zhang
Keyword(s):  
Temperature Distribution ◽  
Hot Spots ◽  
Hot Spot ◽  
Transformer Oil ◽  
Distribution Characteristics ◽  
Thermal Circuit ◽  
Transformer Winding ◽  
Overload Capacity ◽  
The Impact ◽  
Spot Temperature

The temperature of the hot-spots on windings is a crucial factor that can limit the overload capacity of the transformer. Few studies consider the impact of the load on the hot-spot when studying the hot-spot temperature and its location. In this paper, a thermal circuit model based on the thermoelectric analogy method is built to simulate the transformer winding and transformer oil temperature distribution. The hot-spot temperature and its location under different loads are qualitatively analyzed, and the hot-spot location is analyzed and compared to the experimental results. The results show that the hot-spot position on the winding under the rated power appears at 85.88% of the winding height, and the hot-spot position of the winding moves down by 5% in turn at 1.3, 1.48, and 1.73 times the rated power respectively.

scholarly journals Heat Distribution of Micro Turbocharger Cooling System for Motorcycle Application

2019 ◽  
Vol 8 (3) ◽  
pp. 308-314
Keyword(s):  
Experimental Research ◽  
Piston Ring ◽  
Cooling System ◽  
Heat Distribution ◽  
Water Pump ◽  
The Past ◽  
Electric Water Pump ◽  
Air Blower ◽  
Turbine Bearing ◽  
The Impact

The heat produced in turbocharger has the potential to destroy the bearing system and the oil piston ring. For the past years, the researchers have focused on heat transfer of micro turbocharger. The lack of research on the cooling system of the turbocharger has motivated the author to publish this paper. In this paper, the electrical water pump with air blower is used to reduce the heat effect. The impact of adding electric water pump o heat distribution on turbocharger has been discovered by conducting experimental research. The experimental research was conducted on one cylinder, two-stroke with Lifan engine 160 cc equipped with the turbocharger. The temperatures of the turbine, bearing housing, coolant inlet and outlet are measured and analyzed in this turbocharged engine test rig.

Temperature Distribution Optimization of an Air-Cooling Lithium-Ion Battery Pack in Electric Vehicles Based on the Response Surface Method

2019 ◽  
Vol 16 (4) ◽  
Author(s):  
Xiangping Liao ◽  
Chong Ma ◽  
Xiongbin Peng ◽  
Akhil Garg ◽  
Nengsheng Bao
Keyword(s):  
Temperature Distribution ◽  
Lithium Ion Battery ◽  
Electric Vehicles ◽  
Cooling System ◽  
Lithium Ion ◽  
Battery Pack ◽  
Maximum Temperature ◽  
Air Cooling ◽  
Optimized Design ◽  
Original Design

Electric vehicles have become a trend in recent years, and the lithium-ion battery pack provides them with high power and energy. The battery thermal system with air cooling was always used to prevent the high temperature of the battery pack to avoid cycle life reduction and safety issues of lithium-ion batteries. This work employed an easily applied optimization method to design a more efficient battery pack with lower temperature and more uniform temperature distribution. The proposed method consisted of four steps: the air-cooling system design, computational fluid dynamics code setups, selection of surrogate models, and optimization of the battery pack. The investigated battery pack contained eight prismatic cells, and the cells were discharged under normal driving conditions. It was shown that the optimized design performs a lower maximum temperature of 2.7 K reduction and a smaller temperature standard deviation of 0.3 K reduction than the original design. This methodology can also be implemented in industries where the battery pack contains more battery cells.

Analysis of Hot Spots Evolution on Brake Disc Using High-Speed Infrared Camera

2009 ◽  
Vol 417-418 ◽  
pp. 317-320 ◽  
Author(s):  
Jeong Guk Kim ◽  
Sung Tae Kwon ◽  
Sung Cheol Yoon
Keyword(s):  
Hot Spots ◽  
High Speed ◽  
Hot Spot ◽  
Degradation Mechanism ◽  
Low Frequency ◽  
Infrared Camera ◽  
Material Design ◽  
Brake Disc ◽  
Ir Camera ◽  
Thermal Phenomenon

The hot spot generation has been considered as the main degradation mechanism in railway brake disc. Therefore, the understanding of hot spots, also called hot judder, which is undesirable low frequency vibrations developed by non-uniform contact area between brake pad material and brake disc, is important for a better understanding of material design as well as enhancement of materials properties in railway brake disc. Also, infrared (IR) thermography is a powerful NDE technique for the characterization of thermal phenomenon in engineering components and/or systems including engineering materials. The high-speed IR camera provides the measurement of temperature change during brake operation as well as the images of temperature contour on the brake disc surface. In this investigation, damage evolution due to generation of hot spots on railway brake disc was investigated using the infrared thermography method. Moreover, based on obtained thermographic images of hot spots, the hot spots and thermal damage of railway brake disc during braking operation were qualitatively analyzed.

Adaptive Hot-Spot Cooling of Integrated Circuits Using Digital Microfluidics

2005 ◽  
Author(s):  
Phil Paik ◽  
Vamsee K. Pamula ◽  
Krishnendu Chakrabarty
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Hot Spots ◽  
High Performance ◽  
Cooling System ◽  
Hot Spot ◽  
Digital Microfluidics ◽  
Ic Design ◽  
Spot Cooling ◽  
Digital Microfluidic

Thermal management is becoming an increasingly important issue in integrated circuit (IC) design. The ability to cool ICs is quickly reaching a limit with today’s package-level solutions. While a number of novel cooling methods have been introduced, many of which are microfluidic approaches, these methods are unable to adaptively address the uneven thermal profiles and hot-spots generated in high performance ICs. In this paper, we present a droplet-based digital microfluidic cooling system for ICs that can adaptively cool hot-spots through real-time reprogrammable flow. This paper characterizes the effectiveness of microliter-sized droplets for cooling by determining the heat transfer coefficient of a droplet shuttling back and forth in an open system over a hot-spot at various speeds. Cooling is found to be significantly enhanced at higher flow rates of droplets. In order to further enhance cooling, the effect of varying droplet aspect ratio (width/height) in a confined system was also studied.

Optimization of Thermoelectric Coolers for Hotspot Cooling in Three-Dimensional Stacked Chips

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Matthew Redmond ◽  
Satish Kumar
Keyword(s):  
Power Consumption ◽  
Power Distribution ◽  
Hot Spots ◽  
Cooling System ◽  
Hot Spot ◽  
Three Dimensional ◽  
Optimization Methods ◽  
Thermoelectric Coolers ◽  
Robust Solution ◽  
3D Chip Stacking

Three-dimensional (3D) chip stacking architecture is expected to reduce form factor, improve performance, and decrease power consumption in future microelectronics. High power density and nonuniform power distribution in stacked dies are expected to bring significant thermal challenges for 3D packages due to localized hot spots. Embedded thermoelectric coolers (TECs) have potential to provide reliable and localized cooling at these hot spots. In this work, peak package temperature or active cooling per power consumption of TECs are optimized, considering applied current and thickness of TECs as parameters, for a 3D electronic package with two stacked dies. Each die has two hot spots and one TEC is paired with each hot spot. Three different optimization methods are considered in order to ensure a robust solution. The optimization suggests that both the peak temperature in package and energy efficiency of the cooling system can be significantly improved through the optimization of TECs. TECs are also compared against a configuration where they are replaced by copper blocks or thermal vias. A total of 4.7 °C of additional localized cooling is observed using TECs which is beyond what is achievable with copper vias in place of the TECs. The study also suggests that it is better to use TECs to cool only the hottest portions of the package to avoid introducing additional thermal resistance and Joule heating in the package.

scholarly journals Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 110
Author(s):  
Dmitry Bisikalo ◽  
Andrey Sobolev ◽  
Andrey Zhilkin
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Temperature Distribution ◽  
Hot Spots ◽  
Transfer Rate ◽  
Hot Spot ◽  
Mass Transfer Rate ◽  
Three Dimensional ◽  
Jet Trajectory ◽  
Dominant Influence

In this paper, the characteristics of hot spots on an accretor surface are investigated for two types of polars: the eclipsing synchronous polar V808 Aur and the non-eclipsing asynchronous polar CD Ind in configuration of an offset and non-offset magnetic dipole. The drift of hot spots is analyzed based on the results of numerical calculations and maps of the temperature distribution over the accretor surface. It is shown that a noticeable displacement of the spots is determined by the ratio of ballistic and magnetic parts of the jet trajectory. In the synchronous polar, the dominant influence on the drift of hot spots is exerted by variations in the mass transfer rate, which entail a change in the ballistic part of the trajectory. It was found that when the mass transfer rate changes within the range of 10−10M⊙/year to 10−7M⊙/year, the displacement of the hot spot in latitude and longitude can reach 30∘. In the asynchronous polar, a change in the position of hot spots is mainly defined by the properties of the white dwarf magnetosphere, and the displacement of hot spots in latitude and longitude can reach 20∘.

Local Hot Spots of Electric Water Pump Casing Over Various Pumping Loads

2021 ◽  
Author(s):  
Younghyeon Kim ◽  
Yoora Choi ◽  
Sangseok Yu
Keyword(s):  
Hot Spots ◽  
Water Pump ◽  
Electric Water Pump

Thermal Management of an Air-Cooled PEM Fuel Cell: Cell Level Simulation

2012 ◽  
Author(s):  
M. Andisheh Tadbir ◽  
S. Shahsavari ◽  
M. Bahrami ◽  
E. Kjeang
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Temperature Distribution ◽  
Thermal Management ◽  
Rejection Rate ◽  
Thermal Design ◽  
Temperature Gradients ◽  
Maximum Temperature ◽  
Cell Level ◽  
Heat Rejection

Air-cooled polymer electrolyte membrane (PEM) fuel cells have recently been the center of attention mainly because of the simplicity they bring into the fuel cell industry. Their main advantage is the elimination of balance-of-plant subsystems such as the liquid coolant loop, heat exchanger, compressor, and air humidifier which greatly reduces the complexity, parasitic power, and cost of the overall system. In air-cooled fuel cells, air is used as a combined oxidant and coolant. However, the net power output is limited by the heat rejection rate and the overall performance and durability are restricted by high temperature gradients during stack operation. An important initial step toward this goal is accurate knowledge of the temperature distribution in the stack in order to optimize heat removal by suitable thermal management strategies. In the present study, a three dimensional numerical model is developed that can predict the temperature distribution in cell level with an acceptable accuracy. Using this methodology, the maximum temperature in the stack as well as temperature gradients, which are two essential operating parameters for air-cooled fuel cells, can be obtained. The model is validated using experimental data for the 1020ACS fuel cell stack from Ballard Power Systems. A parametric study is performed for bipolar plate thermal conductivity and overall thermal characteristics on the cell level to examine the effects of these parameters on the maximum stack temperature, temperature gradient in the cell, and overall heat rejection rate. Based on these results, recommendations are provided for improved thermal design of air-cooled fuel cells.

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