Lin Ruan

Steady-state performance of evaporative cooling system of stator busbar in hydro-generator

The natural circulation evaporative cooling system is a new kind of method for the cooling of stator busbar of hydro-generator, with the advantage of high-security, energy-saving and high efficiency. The feasibility of this method has been validated through the experimental and theoretical analysis in previous researches. In this article, an experimental table of natural circulation evaporative cooling system of stator busbar was established and the steady-state operation characteristics of system were analyzed by experiments. The wall temperature distributions of stator busbar show that the cooling effect of this new cooling technology is satisfactory. The system work pressures were discussed, which is closely related to the system sealability. The flow characteristics of coolant under different work conditions were analyzed. The research results in this paper provide the important basis for the practical application of this new cooling method.

Analysis of gas-liquid-solid stator-insulation system in the evaporative cooling turbogenerator

Evaporative cooling turbogenerator has a totally different insulation system from conventional turbogenerator. Core, windings and end structures are all be immersed in the evaporative cooling medium. The new insulation system is consisted of original solid insulation materials and gas-liquid mixed cooling medium. New designed gas-liquid-solid stator-insulation system makes full use of evaporative cooling mediums excellent performance in cooling and insulation. Thence, the new insulation system has also undertaken the cooling task in the turbogenerator. Firstly, this paper introduced the theory of gasliquid-solid stator-insulation system in the turbogenerator. Secondly, the paper selected suitable solid stator insulation material according to theoretical analysis. Finally, based on the finite element calculation software, electric field distribution and heat transfer situation of the new structure are calculated and analyzed. The results showed that gas-liquid-solid stator-insulation system performs well in the evaporative cooling turbogenerator.

Design of experimental device used for heat transfer research of single-phase and two-phase spray cooling

Spray cooling is a very efficient mean for dissipating high heat flux with low volumetric flux and Low surface temperature, which is used in many fields. However, there are many differences about the heat transfer mechanism of spray cooling academically. This paper introduces in detail an experimental device, which can be used for heat transfer research of single-phase and two-phase spray cooling. The analysis of experimental data from this device is presented finally, which will be a good reference for the design of the real spray cooling equipment.

Thermal simulation of fully-immersed evaporative cooling switching mode power supply

The evaporative cooling technology has high cooling efficiency and high reliability and it is a promising cooling method which can be applied to switching mode power supply (SMPS). Thermal simulation is an effective way to analyze the performance of the cooling system, and can provide guidance for the optimization of SMPS. In this paper, thermal simulation models of fully-immersed evaporative cooling SMPS and forced air cooling SMPS are established and the simulation results of the two models are compared to demonstrate the advantages of the fully-immersed evaporative cooling technology. The simulated temperature distribution of fully-immersed evaporative cooling SMPS is consistent with the experimental data, thus the accuracy of the thermal simulation model is verified.

Study on the nonlinear characteristics of the inclined self-circulating evaporative cooling system for wind power generator

The evaporative cooling system for wind power generator inclines at an angle of 3∼5 degrees. Due to the special structure, it forms a liquid-gas two-phase self-circulation. Two-phase flow self-circulating system is a typical nonlinear dynamic system. So it is important to study the nonlinear characteristics. In this paper, the nonlinear characteristics were studied through theoretical analysis and experiment, according to the design parameters of 2MW evaporative inner cooling wind power generator.

Stability analysis of voltage sampling circuits applied to switching mode power supply with fully-immersed evaporative cooling

Chip resistors are widely used in switching mode power supply (SMPS). The output voltage sampling circuit of PFC is usually composed of several series-connected chip resistors. When fully-immersed evaporative cooling is applied to SMPS, a rise of PFC output voltage occurs after a period of operation, which is caused by resistance increase of the chip resistor applied to voltage sampling circuit. This paper investigates the reasons and influence factors of the resistance increase by experiment. Three voltage sampling circuits made up of six different kinds of chip resistors, powered by different voltage levels are designed and operate in evaporative coolant for a period of time. The experimental results are analyzed to reveal the external influence factors of resistance change. The energy spectrum analysis is conducted to analyze the causes of the problem from the perspective of chemistry. At last, the solution methods are discussed.

Experimental research on atomization parameters in spray cooling system

Atomization parameters of liquid droplets in the spray cooling system-droplets velocity, droplets diameter, droplets distribution and others influence significantly on the heat exchange efficiency. This paper uses Phase Doppler Particle Analyser(PDPA) to make a precise measurement on atomization parameters on the spray cooling system used pressure atomizing spray nozzle. Then described the distribution of atomization parameters and summarized its regularity. Through the fitting on large quantities of data obtained in test, its practicable to get the correlation formula between atomization parameters and pressure. Quantitative links between flow and atomization parameters will have an important reference to quantitative design of spray cooling system.

Data monitoring system for evaporative cooling ECR based on LabVIEW

The electron cyclotron resonance ion source magnet is a typical super-high power density magnet, and the evaporative cooling technology is an ideal cooling method for the coils of magnet. In order to ensure the evaporative cooling ECR data monitoring system safe and stable operation, this paper developed a data monitoring system. The system was developed by LabVIEW software based on the OPC technique. This system was designed according to the specific character of evaporative cooling ECR. It has the function such as real-time data acquiring, data display, data analysis, data processing and data storage.

Experimental study and CFD coupling simulation of spray cooling physical process

Spray Cooling is an efficient mean for dissipating high heat flux, which is used in many fields especially in electrical and electronic equipment. During the process cooling medium is broke up into fine droplets by atomization nozzle and then they are spayed on the heat surface to perform the cooling work. To further study spray cooling, Its important to make exact mathematics description about the whole process, which has rarely been done by now. The paper conducts CFD coupling simulation for this process and makes comparison and analysis with the results.

Structure improvement and optimization of turbogenerator based on evaporative cooling technology

In evaporative cooling turbogenerator, all structures are immersing in evaporative cooling medium. Traditional evaporative cooling turbogenerater is reformed on the basis of air-cooled turbogenerater. Therefore, the amount of cooling medium is relatively large. We need to find the right improvement program to reduce the amount of cooling medium and to ensure cooling effect as good as possible. On the basis of the structure of air-cooled turbogenerator, this paper proposes improvement and optimization of turbogenerator structure to take full advantage of evaporative cooling technology. The structure especially for evaporative cooling technology is proposed. Whats more, this paper designs new flow channels for cooling medium to ensure perfect cooling effect and insulating properties. Furthermore, this paper discusses the methods to decrease the amount of cooling medium in order to reduce the cost.