Papers by Keyword: Water Cooling

Abstract: The present paper describes the determination of boundary conditions of the 10 kVA plasma reactor graphite electrode cooling. The water cooler installed on the lid of the reactor, connected in open circuit, sustains the permissible service temperatures in the analysed area of the reactor. With the monitoring of the coolant flow and temperatures at the inlet and outlet of the cooler, the heat flux necessary for the design of a closed circulation cooling circuit was determined. Software support of HTC-FC (heat transfer coefficient – natural convection) and simulation software ANSYS CFX were used to solve the design and functionality of the proposed solution. This software is designed for the numerical calculation of differential equations describing fluid flow and heat conduction with the use of the finite volume method. With the application of time-dependent boundary conditions in the simulation tool ANSYS CFX, we acquired information about the temperature distribution of the cooling medium during the operation of the described technology and also about the change in the variation of heat flux between the environment and the proposed container.

Abstract: Because of the non-uniformity of the section shape of rail and complexity of its temperature changing, the degree of thermal expansion and contraction of section must be different which leads to the interior stress is produced inevitable in it. The residual stress in rail is elastic stress and its maximum value is elastic limit stress. They affect the dimension stability, mechanical property, deformation and etc. And it is the important factor of rail quality. This paper builds a finite element model of temperature field through the MSC.Marc software during the process of heating and cooling of 55Q rail, which simulates the rail stress field of air cooling and water cooling. Our paper conducts the experiments on the rails of same material and condition and also selects the temperature and stress of appointed nodes to analyze them. The results of experiments and simulations are very identical. Simulating the residual stress of air cooling and water cooling, the result is that residual stress of water cooling is bigger than that of air cooling. This consequence gives the reference for planning the suitable heat treatment and improving the service life.

Abstract: This study mainly investigates the influence of electronic water cooling system on high power heat generation device at different cooling water inlets with vortex fins or not, hence, heat dissipation experiments are going to carried out on the conditions of three cooling cases: hollow case I, hollow case II and vortex-fin case. From this experiment, it can be seen that the heat dissipation efficiency of hollow case I is reduced by 10% as compared to that of hollow case II, and the heat dissipation efficiency of vortex-fin case is also reduced by 10% as compared to that of hollow case I, that is, water cooling system with vortex-fin has very excellent effect on heat dissipation.

Abstract: High Voltage Direct Current Transmission (HVDC), known as a future energy "highway", plays a key role in the history of electric power system development. In this paper, the present status and future prospect of HVDC convertor valves cooling system in china is analyzed. The performance of HVDC convertor valve cooling system is affected by dry, high temperature, cool weather and sand. Air cooling system is referred to be the most suitable outside cooling system of convertor valve in water scarce areas due to its many advantages such as the antifreezing ability, sand prevention and zero emission of sewage. A hybrid cooling system for cool storage system combined with air cooling system was presented. The experimental result shows this system can be used in desert area like Hami area etc.

Abstract: In this paper a new type of coolers for electric vehicle on-board chargers is presented, which is based on semiconductor refrigeration technology. Using TEC1-12706 we design a cooler for an on-board charger whose power is 3.3kW. And a thermally driven water cooling system is presented to cool the hot end of the semiconductor chilling plate. Semiconductor chilling plates have the advantages of small size, low weight, dust prevention, seismic resistance, non-noise pollution and non-mechanical wear. So they can obviously improve the performances of the coolers used now. Experiments show that the cooler designed can cool the charger well.

Abstract: This document focuses on motors and frequency conversion equipments of stations of West-to-East Gas Pipeline, and introduces the present main cooling ways. Against water consumption, power consumption, and other economical index, analyze the selection process of cooling scheme in engineering design. Compare with the cost, workload of operation and maintenance of water cooling, air cooling and motor cooling. The result shows that water cooling is practicable in West-to-East Gas Pipeline and has validated in the established engineering. The method of scheme comparison proposed by this paper provides a reference for subsequent design.With the development of electronics technology, medium voltage high power frequency conversion speed regulation technology is increasingly mature. The technology that frequency conversion motor drives compressor unit has been gradually used in the long distance pipeline pressure field of oil and gas under the condition of reliable power supply, to replace the traditional gas turbine, and becomes the first choice of the pressurization equipment of the long distance pipeline, because of advantages of high technology, high efficiency, energy conservation and environment protection, economic benefits and so on^[1-3].Stations of West-to-East Gas Pipeline are usually electrical driven. When the compressors operate, motors and frequency converters will produce large amounts of heat, which affects running state and equipment life. So choosing the economic and technological cooling water scheme is important for stations and the whole network to operate safely and stably^[4-6].

Abstract: Stainless steel sheets are successively heated to a temperature of 1150°C and cooled until ambient temperature during the production process. Requirements for high cooling rates of stainless steel sheets producers lead to use water as a cooling medium. The information about cooling intensity (heat transfer coefficient) of different nozzles configurations is necessary for designing cooling sections. Although many researchers deal with water spray cooling, actually a general correlation for predicting heat transfer coefficient for wide range of nozzles configurations does not exists. That is the reason why heat transfer coefficient for different nozzles configurations can be only obtained by laboratory measurements. Heat transfer coefficient is mostly influenced by water impingement density and impact velocity. However other factors e.g. water temperature and velocity of the sheet can influence the heat transfer coefficient. Optimized design of the cooling unit with high cooling intensity and low water consumption was achieved by appropriate choice of these parameters. The moving experimental sheet was cooled from a temperature of 900°C to a temperature of 50°C with various configurations of nozzles. The tests shown that heat transfer coefficient was increasing with water impingement density and impact velocity. Increasing water temperature from 20 °C to 80 °C caused a decrease of the heat transfer coefficient and Leidenfrost temperature. The effect of velocity is negligible when velocities are between 25 and 100 m/min. The cooling unit was designed according to laboratory measurements to fulfill the stainless steel producer's requirements. The measurements which were done in an industrial plant confirmed the accuracy of heat transfer coefficient obtained in the laboratory. The maximum difference between laboratory and plant measurements was 15%.

Abstract: This article introduces a high-voltage three-phase asynchronous motor soft-starter via thyristor that is suitable for water cooling system of steel mill. It improves motor start and stop characteristics, effectively eliminates water-hammer" effect caused by traditional direct start and stop, and is making more and more important positive impacts in the water cooling system of steel mill.

Abstract: Under the action of annual change and sudden drop of air temperature, thermal induced cracking will occur in concrete dam during the operation period. For exploring the temperature control measures for crack prevention, taking a concrete gravity dam section as the research object, sensitivity analyses to the factors which affecting the water-cooling effect are conducted with 3D FEM, some significant suggestions for the water cooling are presented. The results show that, the stresses of the dam surface will decrease to a certain extent after water cooling in the operation period using the cooling water pipe which embedded during construction period, and the cracking risk of the dam will reduce. The study provides a new train of thought for the temperature control and crack prevention of the mass concrete during the operation period.

Abstract: The mechanical properties of heated granite subjected to two different cooling ways, namely cooled in the water (fast-cooling) and cooled in the air (slow-cooling) at room temperature, were studied respectively. The effects of the heating temperatures and cooling ways on the failure mode and failure mechanism of heated granite were analyzed. The tested results indicated that the longitudinal wave velocity, uni-axial compressive strength, and initial elastic modulus of heated granite decreased with the increasing heating temperature, especially for those subjected to the fast-cooling way compared to those subjected to slow-cooling way. To the contrary, the peak strain increased as the heating temperature increases, and the peak strain was bigger for the slow-cooling way than for the fast-cooling way. The analysis of the experimental results indicated that the water cooling accelerated the deterioration of the internal structure of heated granite and resulted in undesired mechanical properties.