Theoretical And Experimental Research On Magnetorheological Fluid Seal Of Circular Cooler

The rapid development of steel industry in China, especially the continuousimprovement of production technique of blast furnace, makes the cooling process ofsinter become very important during sintering. Meanwhile it also prompts theimprovement of cooling equipments, among which the circular cooler has been mostwidely used in the sintering plant because of its significant cooling superiorities. As withdevelopment of large scale sintering machine, the forced draft circular cooler has becomethe main cooling equipment and is now gradually replacing the down draft circular coolerin large and middle scale steel corporations due to its obvious advantages, such as thicksinter bed operation, fast cooling rate after sintering, high exhaust gas temperature and soon, but it also serious air leak as a result of its design defect. On the one hand, it causeshigh energy consumption of the blower and poor cooling effect of sinter, on the otherhand, it causes low temperature waste heat, which result in low waste heat utilization andalso leads to energy waste and environmental pollution because of the exhaust emission.To solve the above two problems, some research works have been done as follows:On the basis of the theories of magnetostatic field and fluid dynamics ofmagnetorheological fluid, magnetorheological fluid can be regarded as Bingham fluid,according to its rheological property, to obtain the magnetic force imposed onmagnetorheological fluid under magnetic field. Basic equation of yield stress ofmagnetorheological fluid under magnetic field is got based on basic principles ofNewtonian fluid. The working modes of magnetorheological fluid and the workingprinciple of circular cooler are discussed, which provide technical guidance for thedesign of magnetorheological fluid seal structure.The major structure of circular cooler is discussed, combined with the workingmodes of magnetorheological fluid and the working principle of circular cooler,magnetorheological fluid seal structure of circular cooler is designed here. The pressureequation is developed here whose approximate solution can be obtained by mathematicalidentical equation. It provides theoretical reference for other seal methods of circular cooler.The discussion on the coupling of magnetic and fluid flow problems ofmagnetorheological fluid seal of circular cooler is made here, and the finite elementsoftware is chosen here to deal with the coupling problem. The simulation model ofmagnetorheological fluid seal of circular cooler is established, and numerical simulationis carried out after the coupling of magnetic and fluid flow equations and the initial andboundary conditions are inputted into the software, and then the distributions of magneticfield and flow field for different seal gaps are obtained, which prove that the reliability ofmagnetorheological fluid seal. According to the yield stress change curves at the side andbottom of non-magnetic separator, the yield stress equations are attained with the optimalapproximation method. The pulling forces needed for moving the non-magnetic separatorare calculated and the appropriate seal gap is obtained, which offers an importantnumerical basis for the application of magnetorheological fluid seal technique.According to experimental requirements, a magnetorheological fluid seal test bed isestablished, and the magnetorheological fluid seal test equipment is designed and the airtightness, maximum pressure and pulling force causing nonmagnetic separator to movefreely are tested with experiment method, which provides technical support for the designof magnetorheological fluid seal structure and application and popularization ofmagnetorheological fluid seal technique.