Hydrostatic equilibrium

About: Hydrostatic equilibrium is a research topic. Over the lifetime, 2451 publications have been published within this topic receiving 62172 citations.

Deformation Analysis for Hydrostatic Rotary Table of Heavy Duty CNC Machine Tool

Abstract: The deformation of constant flow and closed type hydrostatic rotary table of heavy duty CNC machine tool has a great influence on the film thickness because of its large diameter, high load-bearing. According to the circular plate deformation theory of elasticity, differential equations of worktable deformation are derived in the simply supported conditions when bearing uniform force of different locations. Displacement curves of worktable are obtained. Force and deformation weaknesses of hydrostatic rotary table are found, which can provide theory basis for supporting location of heavy workpiece machining and whether oil film is failure or not.

A Discontinuous Galerkin Method for Non-hydrostatic Shallow Water Flows

Abstract: In this work a non-hydrostatic depth-averaged shallow water model is discretized using the discontinuous Galerkin (DG) Method The model contains a non-hydrostatic pressure component, similar to Boussinesq-type equations, which allows for dispersive gravity waves The scheme is a projection method and consists of a predictor step solving the hydrostatic shallow water equations by the Runge-Kutta DG method In the correction the non-hydrostatic pressure component is computed by satisfying a divergence constraint for the velocity This step is discretized by application of the DG discretization to the first order elliptic system The numerical tests confirm the correct dispersion behavior of the method, and show its validity for simple test cases

Temperature Field of Hydrostatic Supporting Disk in Different Viscosity and Rotational Speed

Abstract: With heavy hydrostatic bearing as the research object, establish oil film viscosity-temperature equation. Adopt finite volume method, respectively calculates the oil film temperature field under different rotate velocity in Invariant viscosity and variable viscosity, revealing the oil film temperature arise influence rule of hydrostatic bearing on the viscosity and rotate velocity. The results show that the viscosity and rotate velocity have a great influence on the hydrostatic bearing oil film temperature rise, but the effect regularity varied. The calculated results that provide a theoretical basis for the hydrostatic bearing structure design and bearing deformation calculation, and have very important significance on improve the reliability and precision of the whole machine tools.

Development of a 3D non-hydrostatic pressure model for free surface flows

Abstract: A three-dimensional, non-hydrostatic pressure, numerical model for free surface flows is presented. By decomposing the pressure term into hydrostatic and non-hydrostatic parts, the numerical model uses an integrated time step with two fractional steps. In the first fractional step, the momentum equations are solved without the hydrostatic pressure term using Newton's method in conjunction with the generalised minimal residual (GMRES) method. This combined method does not require the determination of a Jacobian matrix explicitly but simply the product of the Jacobian and a vector, thereby reducing the amount of storage required and significantly decreasing the overall computational time required. By using Newton's method, the numerical model can handle implicitly almost all variables, unlike many other numerical models. Hence numerical stability is achieved effectively. In the second fractional step, the pressure-Poisson equation is solved iteratively with a preconditioned linear GMRES method. It is shown that preconditioning reduces the processing time dramatically. After the new pressure field is obtained the intermediate velocities, which are calculated from the previous fractional step, are updated and then these updated velocities preserve the local mass conservation. The newly developed model is verified against analytical solutions, with good agreement.

Thermal deformation of annular recess multi-pad hydrostatic thrust bearing

Abstract: The thermal deformation of the friction pair of hydrostatic bearing of heavy vertical lathe has great influence on the shape of oil film under the conditions of high speed and heavy load.The thermal deformation will result in great changes of the oil flow state,basic assumption and boundary conditions.Thus,it is difficult to use the theoretical lubrication performance formula to predict precisely the lubrication characteristics of the oil film.To solve this key problem,the thermal deformation of rotating workbench and base is simulated based on fluid-structure interaction method,and the law of thermal deformation distribution is revealed.The relationship between the thermal deformation of hydrostatic thrust bearing and rotational speed of the workbench is established.A model to predict the lubrication performance of oil film is proposed considering the thermal deformation.A test rig is established and experiments are carried out.The experiment results are basically in agreement with the simulation results.This work may provide reasonable theoretical basis for design of heat dissipation structure,lubrication and solving deformation problem of hydrostatic thrust bearing.