The Pressure Distortion Coefficient of Clearance Controlled Pressure Balances Evaluated by Using An Analytical Method

摘要

The characterization, as well as the designing, of pressure balances used in high pressure range need the solution of the elastic equilibrium equations and the viscous motion of the fluid in the clearance. The contemporary presence of the mechanical and fluid dynamic aspect and, furthermore the need to obtain an accurate solution of the problem, also in complex units, makes useful to utilise numerical model. Unfortunately, the analytical solutions available in literature not always allow to obtain reliable results in high pressure, because of the notable complexity of the pressure balances used makes the simplified hypotheses of these solutions inapplicable. This, for instance, is the case of the Lame equation, in the hypotheses of a cylinder constituted of homogeneous material, with a constant section and a constant pressure applied along the clearance. On the other hand, the use of complex analytical models not always guarantees an accurate solution. In the present work the authors propose the use of a simple analytical model, based on the Lame equation, that allows the evaluation of the pressure distortion coefficient for pressure balances in clearance controlled mode and also for cylinders constituted by two or more materials.