GB2128259A - Rotating hydraulic machine - Google Patents

Abstract

A rotating hydraulic machine comprising a rotor (26) incorporating a plurality of generally radial hydraulic fluid supply rotor arms (8) fitted at their opposite remote outer ends with transversely directed nozzles (25), the rotor arms (8) being mounted for rotation adjacent a hydraulic fluid circulator (5) incorporating a deflector (30) for collecting hydraulic fluid upon impacting therewith after emerging under pressure from said nozzles (25) and a plurality of guide plates (29) for directing the impacted hydraulic fluid in a collecting trough adjacent the rotor axis and feeding the rotor arms (8) at their adjacent inner ends. <IMAGE>

Description

SPECIFICATION Rotating hydraulic machine This invention relates to a rotating hydraulic machine and is particularly concerned with a rotating hydraulic or hydro-electric machine for electric power generation.

Although a variety of rotating hydraulic machines, such as turbines, are known for electrical power generation, such machines typically require a relatively large mass of hydraulic fluid, specifically water, to flow under pressure into contact with generally radial turbine blades, so that the reaction forces therewith tend to rotate the turbine rotor carrying blades. Thus the kinetic energy of the hydraulic fluid is gradually exhausted as it flows through the turbine from high to low pressure regions thereof, with attendant losses associated with turbulent flow and frictional/viscous contact between the hydraulic fluid and the turbine surface. In other known constructions, such as a bucket wheel turbine, scalloped vanes are impacted by one or more jets of hydraulic fluid under pressure from a stationary nozzle.

The present invention is concerned with a rotating hydraulic machine utilising a jet of hydraulic fluid under pressure from a rotating nozzle and with the advantageous hydro-dynamic effects associated therewith.

According to the invention, a rotating hydraulic machine comprises a rotor incorporating a plurality of generally radial hydraulic fluid supply rotor arms fitted at their opposite remote outer ends with transversely directed nozzles, the rotor arms being mounted for rotation adjacent a hydraulic fluid circulator incorporating a deflector for collecting hydraulic fluid upon impacting therewith after emerging under pressure from said nozzles and a plurality of guide plates for directing the impacted hydraulic fluid in a collecting trough adjacent the rotor axis and feeding the rotor arms at their adjacent inner ends; the ongoing jetting and recirculation of hydraulic fluid being arranged whereby residual energy released as a result of centrifugal action associated with rotation of nozzles is imparted to hydraulic fluid impacting the deflector and a component reaction force sustaining said rotor rotation is achieved.

In a preferred construction, the water circulator comprises a generally annular funnel member axially off-set from said rotor and incorporating a conical baffle plate upon which are mounted a circumferentially-spaced series of generally radial deflector or guide plates disposed to direct hydraulic fluid inward to an annular collecting trough in said rotor.

In such a construction, the rotor desirably comprises a pair of radial fluid supply lines suitably lying along a common diameter, and fitted in fluid communication with said central collecting trough which is mounted axially of the rotor.

The rotor is conveniently coupled to a rotary electric generator and a starting motor axially aligned therewith and desirably on the same shaft thereas; the entire assembly being mounted in a common housing.

The fluid collecting trough of said rotor may comprise a funnel member incorporating a venturi nozzle with a mouth opening into a chamber communicating with the hydraulic fluid passageways in said rotor arms.

There now follows a description of a particular embodiment of the invention, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 shows a verticai part cut-away and part-sectioned view of a rotating hydraulic machine for electrical power generation; Figure 2 shows a plan view of the rotor employed in the machine shown in Figure 1; Figure 3 shows a vector diagram relating to the operation of the machine shown in Figures 1 and 2; Figure 4 shows in vertical section an alternative rotor and fluid circulator construction for use in the rotating hydraulic machine shown in Figure 1; and Figure 5 shows a perspective view of part of a fluid circulator employed in the rotating hydraulic machine shown in Figures 1 and 2.

Referring to the drawings, a rotating hydraulic machine for electrical power generation comprises a rotor assembly 26 mounted on a shaft 1 6 supported in end bearings 3 and 17 and co-operatively arranged in axially off-set relationship to a hydraulic fluid (e.g. water) circulator assembly 5. A starting motor 1 4 and electrical generator 12, which may each be of conventional construction, are also drivably connected to the shaft 1 6 and mounted on support plates 1 3 and 1 5 respectively integral with an overall machine casing 1, which houses the rotor assembly 26 and hydraulic fluid circulator assembly 5.The end bearings 4 and 1 7 are mounted on support plates 2 and 1 5 respectively, also integral with the casing 1.

Electrical supply connections for the generator 12 and starting motor 14 are effected through a slip ring assembly 4 housed within a fluid-tight casing.

Rotation of the shaft 1 6, initially by the starting motor 14, effects rotation of the rotor assembly 26, which comprises a support disc 10 carrying a pair of opposed radial or diametral rotor arms 8 incorporating hydraulic fluid passages and at their remote ends adjustable or metering nozzle valve assemblies 9 incorporating nozzles or jets 25 for directing a controlled jet of hydraulic fluid outward from the hydraulic fluid supply passages in the rotor arms 8. Specifically, the flow of hydraulic fluid from the nozzle 25 is adjustable by means of metering valve 9.

The inner ends of the rotor arms 8 communicate with a collecting trough assembly 24 disposed axially adjacent the hydraulic fluid circulator assembly 5, which comprises an annular shield partially enveloping the rotor assembly 26 and continuing into a frusto-conical funnel, upon which are mounted a series of generally radial guide or deflector plates 29 and surmounted by a deflector shield 30 attached to the fluid circulator assembly 5 by means of clamping and spacer bolts 6.

The co-operative arrangement of the rotor assembly 26 and the fluid circulator assembly 5 is such that hydraulic fluid emerging from the nozzles 9 is caught or tripped by the annular rim of the deflector shield 30 and inwardly directed flange lip of the deflector shield 30 and drawn upwardly into the scoop or funnel formed between the deflector shield 30 and the conical disc portion of the circulator 5 and therefrom into the collecting trough 24 of the rotor assembly 26.

As may more readily be appreciated from Figures 2 and 3, the motion imparted to the hydraulic fluid by rotation of the rotor 26 produces component velocities and forces which are utilised to sustain the rotation. In particular, hydraulic fluid emerges from the nozzles 25 in a direction of velocity vector or arrow 20, this representing the centre line or axis of the nozzle or jet 25, and this centre line is slightiy off-set at an acute angle 21 to the tangent 27 to the rotational axis of the shaft 16 and thus the rotor assembly 26 at the notional nozzle extremity point 28.

It will be appreciated that, when the jet nozzle 25 is closed, fluid at the nozzle extremity 28 has an instantaneous velocity in a tangential direction of arrow 27, but when the nozzle is opened the dynamic rotational forces are such that the fluid emerges along the nozzle direction 20; this changing component velocity is represented by complementary vector 23 in Figure 3, forming the third side of a triangle velocities, of which the other two sides are the nozzle vector 20, representing the direction of hydraulic fluid flow with the nozzle 25 open and the tangent vector 22, representing the direction of fluid flow when the nozzle is closed.

The kinetic energy associated with the velocity component 23 of the hydraulic fluid is accordingly changed between the nozzle open and closed positions as the nozzle is rotated and it is this energy change which produces an associated reaction force which is used to sustain the rotor rotation after rotation is initiated with the starting motor 1 4. Sustained rotation of the rotor assembly 26 is transmitted to the generator 12.

The magnitude of the velocity component 23 can be calculated by reference to the velocity of fluid emerging from the nozzle 25 and this in turn can be calculated from the rotational speed of the rotor assembly 26, and multiplying this nozzle axis component by the trigonometric sine function of the small acute included angle between the vector 20 and 22.

In practice it is found that the velocity component in question is limited to about 10 meters per second and the related included angle 21 is limited to about 120 for jet velocities in the range 30 to 16 metres per second.

An alternative construction of hydraulic fluid circulator assembly 5 is illustrated in Figure 4. In this construction the rotor assembly 26 has a venturi shaped collection trough 24' communicating at its inner end with fluid passages in the rotor arms 8'. The water circulator 5 comprises a simple dish shape.

The centrifugal pressure P associated with the centrifugal head H in the nozzle 25, the gravitational acceleration G, with the angle 21 previously discussed taken as zero, can all be linked by the following equations (disregarding mechanical losses): Internal nozzle fluid pressure p = P = V2/20.66G H = V2/2G P = H/10.33, with v = O (i.e. no fluid emerging from the jet).

The energy associated with the centrifugal pressure P is generated automatically and with minimal energy loss.

When the needle valve 9 is opened to allow hydraulic fluid to emerge from the nozzle 25, the energy associated with the centrifugal pressure P and stored in the hydraulic fluid is changed into kinetic energy associated with movement of the hydraulic fluid from the nozzle 25; the behaviour being described by the following equations: p + v2/20.66G = P = V2/20.66G and P - p = v2/20.66G It will be appreciated that the centrifugal pressure P is not itself associated with opening or closing of the needle valve, but is present all the time, as it simply arises from the rotation of the rotor assembly 26.

The rate of flow Q of hydraulic fluid from a nozzle 25; the specific mass Z; the reaction force F acting on a nozzle 25 in the opposite direction to the fluid velocity vector 22; the energy input El and the energy output E2 per nozzle can be inter-related by the following equations: F=ZQV El =ZQV2/2 E2 = F . V = ZQV2 The kinetic energy of the fluid jet produced by the centrifugal pressure P = ZQV2/2.

The reaction force F available for maintaining rotation of the rotor assembly 26 is F-El/V=ZQV/2 and thus E2-E1 =ZQV2/2- representing an effective release of energy for improved operating efficiency.

When the needle valve 9 is operated to close a nozzle 25, El and E2 return to 0 and the internal pressure p returns automatically to the centrifugal pressure P virtually instantaneously.

In a trial experiment the following data were produced: With a rotating nozzle radius of 0.49 meters, a rotational speed of 1200 rpm, a nozzle rotating velocity of 62 meters per second was achieved and thus the velocity vector 20 was 60 meters per second; the angle 21 was 100; the fluid flow rate from each nozzle was about 0.00123 cubic meters per second and the practical output per nozzle was about 203 kilogramme meters per second, with a fluid jet diameter of 0.0051 meters.

Claims (3)

1. A rotating hydraulic machine comprising a co-operatively arranged rotor and hydraulic fluid circulator assembly in which hydraulic fluid is rotated therebetween and energy associated with the rotation of the fluid is utilised to achieve the improved operating efficiency, the rotor comprising a plurality of nozzles to direct hydraulic fluid outwardly from the rotor axis into the fluid collector which is arranged to redirect fluid to the inner axial end of the rotor.

2. A rotating hydraulic machine comprising a rotor incorporating a plurality of generally radial hydraulic fluid supply rotor arms fitted at their opposite remote outer ends with transversely directed nozzles, the rotor arms being mounted for rotation adjacent a hydraulic fluid circulator incorporating a deflector for collecting hydraulic fluid upon impacting therewith after emerging under pressure from said nozzles and a plurality of guide plates for directing the impacted hydraulic fluid in a collecting trough adjacent the rotor axis and feeding the rotor arms at their adjacent inner ends; the ongoing jetting and recirculation of hydraulic fluid being arranged whereby residual energy released as a result of centrifugal action associated with rotation of nozzles is imparted to hydraulic fluid impacting the deflector and a component reaction force sustaining said rotor rotation is achieved.

3. A rotating hydraulic machine substantially as hereinbefore described with reference to and as shown in the accompanying drawings.