Abstract:
Due to the complexity of the structure of the high-pressure hard sealing fixed ball valve, its stress situation in the sealed state becomes more complicated, which is difficult to use the traditional analytic method to analyze. In order to ensure its safe operation, in this paper the sealing performance and stress distribution of Class 1500 NPS14 turbo-worm drive hard sealing fixed ball valve are analyzed by finite element method in closed situation. The results indicate that, under the load of medium, a serious stress concentration would be produced on the stem and the root around of gland mounting hole and the macro through leakage flow will be 5 268.594 mL/min, which lead to seriously sealing pressure insufficient. In order to solve the question of valve leakage, the model was optimized by DOE experimental design and Response Surface Analysis. The results show that there is no macro through-hole in the sealing torus and the sealing pressure of the smallest position is 17.739 MPa, which is also greater than the required sealing pressure 9.080 MPa. The seat stress concentration is disappear and the optimization effect is obvious.