Visualization of flow phenomena in hydraulic throttle valves of plastics

Abstract

Using elements made of plastics in hydraulic drives and controls encounters problems, for example related to strength. However, the advantage of solutions with plastics manifests itself, among others in possibility of shaping hydraulic elements in accordance with the assumed requirements. The use of additive manufacturing techniques allows us to make plastic parts with shapes that are unattainable for steel parts. The authors have attempted to determine the influence of the shape of the closing element on the phenomena of flow through the throttling gap in the hydraulic throttle valve. They chose three poppets of different shapes and carried out flow simulations using CFD. They compared simulation results in the form of flow velocity field in the valve chamber with observations obtained with the Particle Image Velocimetry (PIV) technique. In visualization tests, a throttle valve made of transparent materials and markers in a form of air bubbles were used. The tests confirmed the possibility of using air bubbles as markers of the PIV method at low pressure. The presented conclusions indicate the need for further modification of the shape of the closing element as well as of the design of the valve body.

Research on Deformation of Hydraulic Cylinders Made of Plastics

“…Less strength and greater elasticity leads to greater deformations. This was also confirmed in the case of such hydraulic elements made of plastics like gerotor pumps [8][9][10] or valves [11].…”

“…Figure 5b shows that the laser sensors are placed in a special holder (11). The holder is attached to the rigid frame of the test stand (1) and has no direct contact with the tested cylinder, the structure of which deforms and, as a result, moves relative to the frame.…”

A Low-Cost Miniature Electrohydrostatic Actuator System

“…The injection molded pressure relief valve is further documented by Marciniak et al [17], showing successful computational fluid dynamics (CFD, finite element method (FEM), and experimental test results as well as a comparison to an industrial metal relief valve. Another paper from the same research group investigates the flow phenomena in a throttling valve 3D printed from poly(methyl methacrylate) (PMMA) at flow rates up to 10 L/min experimentally and numerically using CFD [18]. They note that some downfalls of 3D-printed plastic include lower strength and larger deformation, and materials such as polylactic acid (PLA) do not have sufficient hardness to form sharp edges.…”

Effect of cone throttle valve pressure on cavitation noise

“…Shi et al [9] experimented with suppressing the cavitation of throttle valves in water hydraulics. Banaś et al [10] studied a cone throttle valve by means of visualisation. In studying a direct‐acting hydraulic relief valve, Yang et al [11] found that the arrow‐shaped compensation structure, an appropriate valve core cone angle, and the secondary valve port can effectively improve the valve performance.…”