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Aiming at the cavitations and noise problem of hydraulic cone valve and based on the radial force analysis of the valve core, the radial deviation of the spool is considered to obtain the changing rules of cavitations and noise.

The solid model of the internal flow field of cone valve is established. The mesh models are divided using ICEM-CFD software. The numerical simulation of the liquid-gas two-phase flow is performed on the cavitation and noise of the flow field inside the cone valve based on FLUENT software. The visible experimental platform for cavitation and noise of hydraulic cone valve is built. According to the contrast of the experimental results, the correctness of the simulation results is verified.

The results show that the radial deviation causes the position of the cavitation accumulates in the valve cavity on the side of the upper cone. In addition, the strength of the cavitation changes slowly with the half cone angle of 45°, and the noise level is the smallest. Furthermore, appropriately increasing the opening degree within a reasonable range can effectively suppress cavitation and reduce the noise level.

The cavitation can be suppressed and the noise level can be reduced by means of changing the three factors, which lays the foundation for the design and theoretical research of the cone valve.

This paper aims to resolve the cavitation problem encountered in cone throttle valves concerning fluid flow performance and pitting from cavitation luminescence, the author studied the flow field within a cone throttle valve set with various valve openings, inlet pressures and outlet back pressures.

The flow and cavitation distribution in the valve under different pressure conditions were obtained in simulations. To confirm these results experimentally, a hydraulic cavitation platform was constructed. The valve was made of polymethyl methacrylate material with high transparency to observe the cavitation directly, as well as cavitation luminescence. The flow characteristics of this valve were measured under various working conditions.

With increasing cavitation strength, a reduction in cavitation on the throttle capacity was more evident. Increasing the back pressure and reducing the working pressure of the valve appropriately improves the flow capacity of the valve, which subsequently improves the performance of the valve. The cavitation luminescence is also linearly related to cavitation intensity. That is, the stronger the flow capacity of the valve, the less likely the luminescence is produced. Moreover, a stronger luminescence intensity worsens the flow performance of the valve.

Owing to the limitation of experimental means and lack of research on bubble shape, the subsequent research will complement this aspect.

With a view to providing theoretical and experimental support, cavitation luminescence is also studied to gain a deeper understanding of the cavitation mechanism in hydraulic valves.

The innovation of this paper is to study the cavitation luminescence in the hydraulic system.

The purpose of this paper is to study the pressure response characteristics of the cartridge electromagnetic relief valve, which offers the problems caused by low pressure response and low efficiency in hydraulic plate shearing machines.

First of all the mathematical model of the cartridge electromagnetic relief valve is deduced to analyze the influence of the relevant parameters on the system pressure response. Then experiments are conducted to research the dynamic characteristics on building and relieving pressure. Through comparison of theoretical and experimental research, the results are found.

The results show that the input flow, working pressure, diameter of adjacent damping hole, and spring stiffness of the main valve have great influence on building pressure of the system, and have no influence on relieving pressure, while diameter of damping hole of control cover plate has influence on the building and relieving pressure of the system.

The research results provide powerful theoretical support for the parametric design of the cartridge electromagnetic relief valve in the hydraulic system of plate shearing machine.

Brief Details of Some of the Components and Equipment Produced by a Number of Companies in Support of the Super VC10 Programme. THE preceding articles have dealt with the raison d'être of the Super VC10, interior engineering, technical details of the combined passenger/freight version, principal differences between the Standard and Super VC10s, development of Economy class seating for B.O.A.C.'s VC10s and aircraft systems. It is the object of this final article to provide some additional information regarding Super VC10 equipment and systems in the form of the contribution made by specific firms to the Super VC10 programme.

A control system for a variable pitch propeller includes pitch lock means operable by the onset of a predetermined negative‐torque in the propeller drive transmission to lock the propeller against pitch fining movement. In the embodiment of Fig. 1, a double acting hydraulic pitch change motor 12 having a fixed brake stop 26 and a fixed feathering stop 27 has a fine pitch line 13 and a coarse pitch line 15. To coarsen the pitch oil is supplied under pressure via line 14, by‐pass 16 and non‐return valve 29 to the left hand side of the motor piston 10, oil on the other side exhausting through line 13. To reduce pitch oil under pressure is supplied to the line 13 from which it branches to act on the right hand side of the piston 10 and to move the pitch lock valve 17 against the action of its spring 22 so that oil from the left‐hand side of the piston can exhaust through said valve into line 14. The port 32 of the reduction gearing driving the propeller shaft 30 is connected to hydraulic piston and cylinder units 33 forming port of a torquemeter so that when negative‐torque is experienced, i.e. when the propeller windmills and drives the engine, the port 32 moves clockwise, thus tripping a lever 25 to raise a spring‐loaded spill valve 23 which connects the fine pitch line 13 with a low pressure line 24, thereby relieving pressure on the valve 17. The spring 22 then closes said valve, forming a hydraulic lock in the motor cylinder so that fining of the propeller pitch with consequent increase in windmilling drag, is prevented. In another embodiment the spill valve is replaced by a multi‐purpose increase pitch valve and the system includes main control, servo, and negative‐torque signal valves so arranged that with the onset of negative‐torque the lock valve 17 closes as in the first embodiment but the coarse pitch line is placed in direct communication with the delivery side of the governor pump. The propeller moves to a coarser pitch, the windmilling and the negative‐torque are reduced, and the propeller is returned to the control of the main control valve.

Flow force is one of the crucial factors affecting the performance of conical throttle valves. The purpose of this paper is to determine the relationship between the flow force and operating parameters of the conical throttle valve.

The flow force of the throttle valve can be obtained by the difference between the axial force and static pressure on the valve spool. In this paper, the internal fluid is divided into two regions and the axial force and static pressure are obtained, respectively. In addition, a two-dimensional axisymmetric simulation model and experimental test are carried out to validate the results of the flow force.

It can be seen that the theoretical, simulation and experimental results exhibit high agreement with each other and the error between them decreases with the increase in the size of the opening. The curves of pressure distribution reveal that the pressure on the spool first decreases then increases when it reaches the minimum pressure at the orifice. Additionally, the minimum pressure decreases with the increase of opening and pressure difference. The results also indicate that the increase in the size of the opening and inlet pressure has a positive effect on the flow force. However, the increase in outlet pressure has a negative effect on the flow force.

In this paper, the flow force calculation model of conical throttle valve is established and the influence of operating parameters on the flow force of conical throttle valve is studied.

THESE notes have been prepared because it is a fact that there is no publication available to the ordinary aeroplane mechanic which gives him the essential information which will guide him in the overhaul and maintenance of hydraulic equipment. There are only one or two books which even touch on the subject other than the official (and very excellent) R.A.F. publication, A.P. 1803.

The purpose of this paper is to study the variation of cavitation scale with pressure and flow in poppet throttle valve, to obtain the cavitation scale under pressure and flow conditions and to provide experimental support for the research of suppressing throttle valve cavitation and cavitation theory.

A hydraulic cavitation platform was set up, a valve was manufactured with highly transparent PMMA material and a high-speed camera was used to observe the change in cavitation scale.

Through experiments, it is found that the pressure difference between inlet and outlet of throttle valve affects the cavitation scale, and the more the pressure difference is, the easier the cavitation will be formed. Under the condition of small pressure difference, the cavitation is not obvious and reducing the pressure difference can effectively suppress the cavitation; the flow rate also affects the cavitation scale, the smaller the flow rate, the more difficult the cavitation will be formed and the lower the flow rate, the more the cavitation will be suppressed.

Because of the magnification factor of the high-speed camera lens, the morphology of smaller bubbles cannot be observed in this study, and the experimental conditions need to be improved in the follow-up study.

This study can provide experimental support for the study of throttle valve cavitation suppression methods and cavitation theory.

Smiths Industries is to supply the head‐up display system for the Sea Harrier. The company will design, develop and make the electronic head‐up display and weapon aiming computer system for the latest version of the HS Harrier which will operate from Royal Navy ships.

Descriptions of the Super VC1O's Hydraulic, Electrical, Flying Controls, Fuel, Air Conditioning and Pressurization, Flight Systems, Radio, Electronics and Anti‐icing Systems. THE June 1962 issue of AIRCRAFT ENGINEERING contained a comprehensive engineering description of the Standard VC10 and one of the articles contained in that issue dealt with systems, testing and equipment. However, the systems were dealt with comparatively briefly and it is therefore the object of this article to describe the principal systems in greater detail. The systems of the Standard and Super VC10 aircraft are essentially similar and the following description is based on British Aircraft Corporation's descriptive engineering notes.