Flue Gas Desulfurization Pump Mechanical Seal Friction Temperature Field Of Study

In the practical operation of the mechanical seals used in flue gas desulfurization (FGD) pumps, if the temperature on the end faces of the seals is too high, the following results will happen:greater friction, thermal deformation, and hot cracking of the seal rings, and vaporization of the liquid film between the seal rings, which will results in the failure of the seals. The approximate analytical solution method and numerical simulation method were adopted to investigate the temperature field distributions of the fiction pairs of the mechanical seals used in the FGD pumps.The friction conditions of the mechanical seal rings include all the liquid lubrication condition and mixed friction condition. Considered heat transfer through the rotor ring and the stator ring, a more reasonable approximate analytical solution method calculating the end face temperature distribution of the mechanical seal rings was proposed based on the previously defined heat conducting angle. The distribution ratio of heat transfer through the rotor ring to the stator ring was determined by the conducting coefficient of the seal ring material and the heat transfer coefficients of the seal rings and the medium, i.e. the heat conducting angle of the rotor ring and the stator ring. The proposed method was compared with the other approximate analytical solution methods, and the results were shown that the definitions in the proposed method were concise, the calculation process was simple, and the calculating results were closer to the practical ones. Moreover, the factors affecting the temperature distribution on the end faces and their affecting laws were analyzed.In addition, the ANSYS finite element analytical software was used to perform the numerical simulation on the steady and transient temperature field distributions of the fiction pairs of the mechanical seals used in the FGD pumps. The PLANE55with the function of axial analysis was used as the thermal analysis unit to solve the temperature field distributions of the mechanical seals. In the steady condition, the temperature field distributions of the mechanical seals with flushing and cooling process and without the process were compared. It was shown that the steady temperature distribution without flushing on the seal end faces turns to be a parabolic shape. The highest temperature and the lowest temperature were located in the place near the inner radius and the outer radius, respectively. The axial temperature gradient on the rotor ring was smaller than that on the stator ring. The transient temperature field distribution of the starting phase of the mechanical seals was also simulated, and the temperature distribution at different time and sketch of temperature varying with time at different points on the seal ring of the mechanical seals were obtained. The transient temperature field distribution was analyzed with the finite element method. It was shown that the transient temperature field distribution of the mechanical seals had the characteristic of posteriority. When the sealing ring near the inner radius was flushed, the highest temperature near the inner radius could be greatly decreased by the process of flushing and cooling, and the highest temperature of the face appears between the inside and outside of the seal ring.At the same time, the temperature calculating results of the approximate analytical solution method and the numerical simulation were compared. The temperature distributions in the axial and radial directions of the seal rings were compared,respectively. The average error of the approximate analytical solution and the numerical simulation solution was analyzed. The factors that affected the temperature distribution of the mechanical seals were studied, including the spin speed, the medium pressure, the spring pressure, and the match of different materials. It was shown that the end face temperature had approximate linear relationships with the spin speed, the medium pressure and the spring pressure. The end face temperature of the match of materials whose coefficients of thermal conductivity were lager was lower than that of the match of materials whose coefficients of thermal conductivity were smaller. The factors affecting the temperature distribution of the mechanical seals were analyzed with the multiple linear regression method.