| The use of flame-proof variable frequency speed regulation technology is able to realize the automation of production process, improve the production efficiency and save the electricity power, which contributes to the comprehensive economic and social benefits. Flame-proof shell technology has to be adopted due to the harsh environment filled with the explosive gas containing methane and coal dust in the underground coal mine where the electrical equipment is installed. However, in order to ensure the electric spark inside the shell not burning off the explosive gas outside the shell, the inverter has to be sealed in the flame-proof shell. The safe use of frequency converter is affected seriously by the heat dissipation of electronic components. At the same time, the condensation effect causing by thermal change also leads to serious short circuit. A flame-proof dual throttling air-conditioning system is put forward to solve the heat dissipation and internal dewing problems of flame-proof converter in the underground coal mine.To start with, the work principle of flame-proof dual throttling cooling and dehumidification air-conditioning system is briefly described. The modular design concept is adopted by dual throttling air-conditioning system. The factors of mine-used explosion-proof safety, reasonable airflow organization and simple structure are also comprehensively taken into consideration for structural design of dual throttling air-conditioning system. Flame-proof shell technology is adopted. The structure design of dual throttling air-conditioning system is completed by theoretical calculation and technical testing. Secondly, the personalized ventilation mode is adopted in view of heating spot location in the converter shell, which implements a targeted intensive cooling mode. It makes the design of air conditioning system achieve the effect of saving energy.According to the refrigeration and cooling dehumidification principle of air conditioning and coupling control technology, air conditioning unit is matched. The experiment is conducted by simulating underground coal mine environment. The experimental result shows that the system reaches the steady state at the refrigeration mode after running 45 minutes, and the maximum internal temperature of the flame-proof shell is 31.7℃. The system reaches the steady state at the dehumidification mode after running 37 minutes. The maximum internal relative humidity and temperature of the flame-proof shell are 33.4% and 36.3℃, respectively. Therefore the proposed system has excellent ability of heat dissipation and avoiding internal dewing. Compared with traditional water cooling system, it is more energy-saving, economical and reliable.Furthermore, flame-proof converter air-conditioning heat dissipation system is numerically simulated by computational fluid simulation software FLUENT because of the single obtaining method of system performance, obtained contours of the heat dissipation model temperature field and the velocity field under the experiment condition and design condition. Cooling effect influence of supply air temperature is analyzed. It can be seen from the results of CFD numerical simulation that simulation and experimental test have a consistent trend and high alignment. Air conditioning system has fast heat dissipation ability and effective way to avoid the internal dewing. The air conditioning system can meet the design requirements through the simulation design condition. That also lays a foundation for optimal structure designing and the popularization of dual throttling air conditioning system.Flame-proof converter air-conditioning heat dissipation system is an exploration and innovation. The experimental test and CFD simulation show that the cooling and dehumidification performance of dual throttling air-conditioning system is superior. And it also has many advantages such as heat dispelling fast, temperature and humidity coupling control, safe and reliable operation and so on. |
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