Prediction of test results to determine the hydraulic resistance coefficient of an axially symmetrical check valve

Abstract

The urgency of the paper is determined by the necessity to predict the results of tests for determining the coefficient of hydraulic resistance of axially symmetrical check valve DN 100-600 with operating pressure up to 20 MPa and operating temperature from plus 50C to plus 3500C according to TS 6981-254-08847871-07. This paper suggests to reduce the volume of tests by excluding the tests for intermediate samples of valves (DN 100, DN125, DN 200, DN 300, DN 500, DN 600) situated in DN between the valve type models (DN 100, DN 175, DN 400) and replaced the tests by calculations in the programme module ANSYS CFX of the calculation complex ANSYS. The results of the tests for determining the coefficient of hydraulic resistance are given. An estimate of hydraulic resistance coefficient values is offered and recommendations for its determination are given. The experimental determination of hydraulic characteristics was carried out in the region of quadratic resistance and in absence of cavitation (the tests were done on water). The region of quadratic resistance comes at Reynolds numbers Re ≥ 2 × 104 for check valve of nominal diameters DN ≤ 250. The region of quadratic resistance ReKB is determined in the process of experimental determination of drag and flow capacity factors for valves of nominal diameters DN ≥ 250. The procedure of determination of ReKB is described in 7.2.3 of GOST 55508-2013. These test results for determination of hydraulic resistance coefficient for valves DN 150, DN 175, DN 400 according to TU 6981-254-08847871-07 can be used when developing acceptance test programs to set the number of tested samples according to the design features and number of versions of check valves (DN 100, DN125, DN 200, DN 300, DN 500, DN 600), replacing the testing by calculation.