DE4033674A1 - METHOD FOR OPERATING A WATER JET DRIVE FOR WATER VEHICLES AND ARRANGEMENT FOR IMPLEMENTING THE METHOD - Google Patents

Abstract

Water-jet drive for water craft with a nozzle whose effective cross-section can be altered depending upon the water flow rate to pump rotation speed = constant ratio, as can its effective direction of propulsion, the effective nozzle cross-section of which can be altered via two mutually independently adjustable flaps (20, 21), whereby one control flap (20) is curved and arranged to be directly dirigible about a bearing fitted in the nozzle body (19) while the other is straight and adjustable for position via two mutually independent adjusting devices (26, 33) with bearings at each end in such a way that they can free a slot for the emerging water jet at their forward end for the nozzle body or at the rear end for the lower edge of the curved flap or at both ends.

Description

The invention relates to a method for operating a Water jet propulsion for water vehicles according to the The preamble of claim 1 and an arrangement for Implementation of the process according to the preamble of Claim 9.

Using all known water as propulsion Jacking devices for watercraft, both Ship propellers of different geometries as well As is known, so-called water jet drives cannot larger speed ranges can be adjusted without that there are adverse effects on efficiency surrender. Variable pitch propellers also have only a limited number Work area, only with a propeller blade position and a propeller speed / progress ratio best efficiency over the entire propeller wing extension can be achieved.

Opposite a ship propeller, the one dealing with the Vessel speed changing, but otherwise inflow speed which cannot be influenced, has the advantage of a water jet that for that Water accelerating pump in all driving ranges and optimal flow to the pump at all pump speeds Blade profiles and thus operating points of the best efficiency  can be achieved if the flow-determining nozzle of the Water jet drive is designed so that their effective cross-section of the outlet during operation can change.

For this purpose, it is known to have the outlet cross section cylindrical nozzle by means of an adjustable, the To adapt the contour of the flexible component.

Here, one is related to the nozzle efficiency optimal jet exit speed of the water jet, one with the speed of the watercraft changing flow velocity of the pump and of itself thus changing depending on the driving speed Throughput out; see. GB-PS 10 63 945.

Another solution provides for the control flaps one Water jet drive in opposite directions around a vertical axis pivotable to support the beam outlet opening Radial pump are connected downstream, through the control valve pen the nozzle cross section according to the equation

should be changed, whereby
A = nozzle cross section (in square inches) and
H = horse power; see. U.S. Patent 30 55 175.

However, this mathematical approach leads to useless Control conditions, since - as can be shown - via the Drive power is not a specific point in the pump map is described, but a curve different Flow rates and thus also different nozzle cross cuts.  

A second requirement for water jet powered water travel witness refers to the ability to trim what basically by a vertical deflection of the jet les is achievable. For the optimal driving style Watercraft at different speeds and thus different buoyancy focus in the longitudinal direction of the watercraft is - as experience has shown has - the change in vertical known as trimming component of the thrust generated more advantageous than one Trim through an additional resistance-generating Trim tabs.

In the case of so-called outboards and Z drives, this is done by Change the angle of the propeller axis to the watercraft achieved. However, this change in the angle of attack results in a different inclined flow of the propeller blades and hence the known disadvantages resulting therefrom.

In water jet drives, it is known for this purpose Exit end of the water jet drive as a cylinder jacket cuts formed by sector-shaped cheeks Assign control flaps in a housing that means Bearing bolts passing through the crossbars on the pump housing a vertical axis is pivoted by one to store the horizontal axis pivoting in opposite directions; see. DE-OS 26 44 743.

It is also known to control such Water jet drive a nozzle with control flaps with in assign a substantially rectangular cross-section, which in Area of the jet outlet opening of the nozzle two in the same direction arc-shaped control flaps of different radii owns; see. DE-OS 37 00 530.8.

All of these controls have the peculiarity that either one possible beam deflection only in a vertical direction  with a coupled simultaneous and not separately controllable reduction of the nozzle outlet surface or a vertical beam deflection upwards and possible below without changing the nozzle cross-section is.

The invention has for its object a method and an arrangement for performing the method for a manual or automatic control of the nozzle exit cross cut regardless of driving speed and as whose sequence is pending at the nozzle outlet cross section to indicate different pressures that an operation of the Water accelerating pump in the area of optimal Guarantees efficiencies in the entire operating range and through a controlled vertical deflection of the driving jet also allows the watercraft to be trimmed, whereby also a large reversal of thrust for the reverse drive and for the braking process is enabled, and that the Arrangement also in towing mode, i.e. in the event of a failure Drive device - drive motor and / or pump - still should generate a usable control pressure.

This object is achieved according to the invention for the method the characterizing features of claim 1 and for the arrangement by the characteristic features of the Claim 9 solved.

Further features of the invention result from the Subclaims.

The method according to the invention makes an optimal one Operation in terms of thrust and efficiency of the water jet drive in all operating areas with regard to speeds and Driving speeds reached because of the changeable effective nozzle cross section "Fw" regardless of the Driving speed "w" depending on the pump speed "n" the associated water flow "Q" is adjusted.  

For this purpose, a, the Throughput "Q" proportional speed "vx" or the associated dynamic pressure "pdynx" in a suitable place "x" within the flow channel as a control criterion for the used nozzle outlet cross section "F", used and

kept constant, where "vx *" is the flow velocity and "pdynx *" the associated dynamic pressure "pdyn" on the Measuring point "x" at the operating point for optimum efficiency the throughput "Q *" and the design speed "n *", and the Speed "vx" or its dynamic pressure "pdynx" the measured value at the current pump speed "n" and the throughput to be regulated mean "Q".

The values "pdynx" and "n" or vx can be used as control signals either a computer and associated automatic Control device supplied or in a suitable form for a manual adjustment of the optimum are displayed.

The invention also allows the vertical component of the effective water jet and thus the trim automatically perform, for the necessary actuation of the Fold the deviation from the target value of the inclination of the Watercraft around the transverse axis with a water jet driven and / or around the longitudinal axis when using two or more water jet drives on the watercraft detected by suitable sensors and the control in suitable signal form are supplied.

Such an arrangement has decisive advantages compared to the usual passive control by trim tabs  or by adjustable wings on hydrofoils or similar watercraft with fully submerged wings or buoyancy bodies that provide additional driving resistance generate whose effectiveness strongly depends on the driving speed depends on and the desired trim to compensate for one stomping or yawing caused by heavy seas the low driving speed which is only permissible in such cases insufficient or not at all.

The nozzle according to the invention has a manufacturing technology easy to control at least partially rectangular Cross section on and allowed to carry out the procedure in addition to an effective change in the nozzle cross-section by changing the position of the two control flaps to each other also through the simultaneous same-minded Adjustment of the two flaps possible change in Vertical component of the effective thrust. Furthermore is by the possible lowering of the front bearing of the lower one Flap almost complete reversal of thrust possible.

Furthermore, by lowering the front end of the lower flap has a bypass opening inside created the nozzle so that as a result of this resulting injector effect an increase in accelerated water mass with lower outlet speed density arises from the nozzle, especially at low Water depth in ports or on rivers the agitation of the Reason reduced and advantageously in the area lower speeds to improve the Beam efficiency and thrust is used.

The water-carrying bypass generated in this way can also can also be used as a passive rudder in towing and generate usable taxpayers.  

Since the component supporting the nozzle is designed as a housing and is pivotally mounted about a vertical axis, wherein this axis can be inclined against the vertical is one Easy and safe cornering. With the housing are all parts of the control, which are the cross-sectional edges nozzle, the vertical thrust deflection and the Generate reverse thrust, indirect or directly connected, resulting in a simple and operational safe and efficient training of the water jet drive leads.

Since at least two flaps are assigned to the housing, whereby one as a cylinder shell segment and the second as a double stored lower flap is formed, and an unchanged distance between the front bearing of the lower flap and the lower end of the upper flap by tabs or the like Components is ensured, the upper flap on have an oppositely curved surface at the lower end, which serves as the upper limit of the nozzle cross section. This is very advantageous because by simultaneously closing the Flow cross-section on the front edge of the lower Control flap in the area of the bearings and on the rear edge between the facing surfaces of the lower and upper Flap the water channel of the entire water jet drive from the exit side is closable, so that a Flow and / or damage to the inner pump parts when the drive is at a standstill in the port is definitely avoided.

The invention is based on several in the Drawing more or less schematically shown Described embodiments.  

Show it:

Fig. 1 is a pump characteristic map with lines of constant rotational speed, throttle lines of constant nozzle cross section, and as a result of the recovered in the inlet part of the velocity head resulting nozzle and pump operation of dots,

Fig. 2 is a parallel projection of a control unit for the nozzle of a water jet propulsion reaction according to the invention,

Fig. 3 a section through the nozzle schematic of FIG. 2 with the associated control valves in a "closed position for downtime"

Fig. 4 is a section through the nozzle schematic of FIG. 2 with the associated control valve is in the "slow travel with a horizontal deflection downwards to reduce the deadrise"

Fig. 5 is a section through the schematically illustrated nozzle of FIG. 2 with the associated control valves in the "lower slow travel with increased by injector amount of water velocity" at the same time position of the control flaps to as "passive rudder"

Fig. 6 is a section through the schematically illustrated nozzle of FIG. 2 with the associated control valve is in the "high-speed travel with reduced nozzle surface and horizontal deflection upward = positive-Aufkimm moment"

Fig. 7 is a section through the schematically illustrated nozzle of FIG. 2 with the associated control valve is in the "high-speed travel with reduced nozzle surface and horizontal deflection downward (negative" Aufkimm- moment ")",

Fig. 8 shows a section through the schematically illustrated nozzle of FIG. 2 with the associated control flaps in the "reverse driving and braking"

Fig. 9 is a parallel projection in schematically Darge provided further steering with two adjustable flaps at both ends in a pivotable about the vertical axis of the nozzle body in the position for "slow travel with negative Trimmoment"

Fig. 10 is a nozzle according to Fig. 9 in the "brakes and reverse travel"

Fig. 11 is a nozzle according to Fig. 9 in the "long-samfahrt with increased by injector amount of water lower speed"

Fig. 12 is a parallel projection in schematically Darge provided further steering with two adjustable flaps at both ends in a pivotable about the horizontal axis of the nozzle body in the position "drive at low speed in a right curve"

Fig. 13 is a nozzle according to Fig. 12 is in the "high-speed travel with a positive trim corresponding to a positive Aufkimmoment"

Fig. 14 is a nozzle according to FIG. 12 in the position "reverse travel or braking" and

Fig. 15 is a control scheme for water jet propulsion systems according to the invention.

In order to facilitate the understanding of the invention, let us know in advance the theoretical relationships are explained.

As is known, w changes with increasing speed of the vehicle through the nozzle of the water jet drive amount of water Qw flowing through surface F according to:

where Hp is the pump head, hw is the speed head of the vehicle:

hw = w² / 2 g (2)

and denotes the ξ-part of the speed level, which in Inlet of the pump through advantageous suction design mouth and the diffuser can be recovered.

In Fig. 1 is in the usual representation of a pump map with the pump head H on the ordinate 1 and the pump throughput Q on the abscissa 2, the pump characteristic 3 constant speed without speed recovery (identical to the pump characteristic at the driving speed w = 0) and the pump characteristic curve 4 with speed recovery 9 , the throttle line 5 for the optimal standing thrust 6 and the throttle line 7 for the optimal thrust 8 at the design speed w.

At standstill, ie a driving speed w = 0, the pump operating point 10 also speaks the nozzle operating point. If the nozzle cross-section remains unchanged, the operating point moves to the new nozzle operating point 11 and consequently to the pump operating point 12 in accordance with the characteristic of the speed characteristic curve due to the higher driving pressure w due to the higher pressure at the nozzle by the value 9 = ξ · w² / 2 g 3 in an area of lower pump delivery heights and poorer pump efficiency, so that now only the lower thrust 13 can be achieved.

From the formula (1) and Fig. 1 it can be clearly seen that with increasing vehicle speed "w" and greater speed recovery, the nozzle cross-section determining the throttle line "F" must be reduced to the size "Fw" by the delivery head / throughput characteristic of the throttle line 5 to the throttle line 7 and the nozzle operating point 11 to the nozzle operating point 14 so that the throughput 15 of the efficiency point 10 of the speed characteristic line 3 of the pump and the highest possible thrust 8 is achieved.

If, on the other hand, the nozzle cross section "F" for the maximum thrust 8 is carried out at the desired maximum speed "w" with "Fw", only a lower thrust 17 corresponding to the throttle line 7 can be achieved compared to the largest possible thrust 6 which is related to the performance.

These criteria naturally apply to the entire speed range of the pump, since the same optimal flow conditions prevail within the pump blading for all points of the parabola 5 through the optimum point 10 .

So it becomes an optimal operation - thrust and impact degree - a water jet drive in all areas of operation - Speeds and driving speeds - aimed, must be about the effective nozzle cross section "Fw" regardless of the Driving speed "w" always depends on the pump rotation  number "n" the associated water flow "Q" adjusted will. There

is the dynamic pressure proportional to the flow Q. pdynx at any point of constant cross section and constant flow direction within the pump or Flow channel can be selected.

If a throughput Q * is reached at the speed n * in the selected optimal map point 10 , a flow velocity vx * and thus the dynamic pressure pdynx * is consequently present in the measuring cross section Fx. Thus, vx * / n * or can also be used for the control criterion Q * / n *.

It can be used to write:

or for the dynamic pressure to be regulated

Here "pdynx *" means the dynamic pressure in the measuring cross section "Fx" at the operating point ( 10 ) optimum efficiency at the design speed "n *" (3) and the throughput "Q *", the pressure "pdynx" the measured value at the current pump speed "n".

An exemplary embodiment for carrying out the method according to the invention will now be described with reference to FIG. 2, only the parts belonging to the invention being shown. Of the flow channel arranged in the forward direction on a watercraft with an inlet having an intake opening at its front end, a pump downstream of the inlet in its central region for drawing in and accelerating water, and a nozzle at the jet outlet opening at its rear end is therefore only the rear End of the pump body 18 shown. The pump body has an approximately circular cross section and merges downstream into a nozzle D formed by a nozzle body 19 , an upper flap 20 and a lower flap 21 .

The nozzle body 19 is pivotally mounted on the pump body in the pivot axis 22, which is only partially shown, and is vertically adjustable at an angle to the pump axis by means of the pivot device 37 ( not shown in any more detail).

The end face 23 of the nozzle body 19 is designed in the form of a circular arc. The underside of the nozzle body is open and closed by the lower flap 21 . The flap 21 movably supported by means of bearing eyes 27 and 32 thus forms the lower boundary of the flow channel and the nozzle. The lower flap 21 also has lateral cheeks 24 which serve to guide the flap 21 in the nozzle body 19 and to limit the water jet laterally when reversing.

The upper flap 20 is rotatably mounted about a pivot axis 25 in bearing eyes 25 'of the nozzle body 19 and adjustable by an engaging on a bearing 31 and on the other hand on the nozzle body 19 pivotally mounted in a bearing eye 38 adjusting device 26 . Furthermore, two adjusting devices 33 are provided between the bearing eyes 32 of the lower flap and the bearing eye 31 of the upper flap 20 .

The lower flap 21 has at its front end bearing 27 , in which the existing adjustment mechanism 28 , the angle levers 39 and the linkage 40 engages direction with which the lower flap can be lowered at this end. Spacer tabs 29 are arranged on the bearing 27 , the other ends of which are pivoted on the upper flap 20 in the bearings 30 .

The operation of the arrangement described is as follows.

By means of the one hand on the upper flap 20 on the mounting eye 31 serving as storage and on the other hand in the mounting eyes 32 also serving as storage at the rear end of the lower flap 21 actuating devices 33 , the effective nozzle cross section by changing the gap 34 between the lower circular arc-shaped Area 35 of the upper flap 20 and the rear edge 36 of the lower flap 21 changeable. With the actuating device 33 in the unchanged position, the lower flap 21 is adjusted simultaneously with the upper flap 20 by the actuating device 26 and thus with a constant gap 34 and thus constant nozzle cross section, only a vertical change in direction of the emerging water jet is generated. In the end position of FIG. 33 , a complete closing of the gap 34 is achieved by the surface 41 of the lower flap 21 being directly supported on the circular surface 35 of the upper flap 20 . In this way, the cross section of the nozzle can be cut when the port is idle and the flow channel can be closed at least on one side, so that contamination is largely avoided.

In FIGS. 3 to 8 the various possible positions of the control valves 20 and 21 with respect to the flow channel serving as a nozzle body 19 and the Abströmrichtungen produced thereby of the drive beam and the lowering of the flap 21 are shown schematically.

In FIG. 5, the "Bypaßstellung" is shown of the nozzle, wherein the air flowing in the cross-section 42 drive jet with the speed 43 of the inflowing through the Bypaßquerschnitt 44 according to vehicle speed 45 water mass by friction and mix a relative to the driving jet lower average exit velocity 46 in cross-section 34 communicates and thus improves the nozzle efficiency in the low driving speed range.

In FIGS. 9 to 11 a second embodiment is shown of such a steering nozzle. The nozzle body 19 , which can be pivoted about a partially shown vertical pivot axis 22 in the pump body 18, has two parallel cheeks 19 , between which the two flaps 21 a and 21 b are guided and in their position on the bearing eyes 27 a, 27 b, 32 by means of adjusting devices (not shown) a and 32 b are adjustable such that both the outlet cross-section is adjustable by the distance 34 between the two rear edges 36 a, 36 b of the flaps 21 a, 21 b and also by simultaneous adjustment of the two rear edges 36 a, 36 b in the same direction the flaps 21 a, 21 b a vertical deflection of the effective beam direction for trimming can be achieved.

By closing the cross sections in the area of the front edges 47 a, 47 b and the gap 34 between the edges 36 a, 36 b, flow through the pump is advantageously prevented when the vehicle is at a standstill and during lay times in port and thus its damage.

For the braking process or for driving backwards, the gap 34 between the rear edges 36 a, 36 b of the flaps 21 a, 21 b is closed, the front edge 47 a or 47 b or both adjusted in such a way that the gap created by the Pump accelerated water can flow out in almost the direction of flow in the pump in the opposite direction and thus produces a thrust opposite to the normal direction of travel. If, on the other hand, the gap 34 is additionally opened, a bypass acting as an injector is created.

In Figs. 12 to 14 is further rotated by 90 ° embodiment shown in Figs. 9 to 11 illustrated control means, here by gleichzei term equidirectional swiveling of the two flaps 21 a, 21 b, the horizontal beam deflection and thus the Control of the direction of travel and by pivoting the nozzle body 19 about the horizontal axis 22, the vertical deflection of the driving jet for trimming is achieved.

From Fig. 15, the interaction of the above beschrie surrounded assembly structure can be seen drive pump nozzle control and power, ie the actuation of the described valves of the nozzle via a controller and a servo in dependence of the available measurements pump speed, Dynamic pressure and / or flow speed in the flow channel, such that the cross section of the nozzle is controlled independently of the speed of the watercraft depending on the speed of the pump and the associated flow rate of water through the flow channel to a ratio of water flow rate to pump speed = constant, whereby the detectable dynamic pressure or the flow velocity in the flow channel and the speed of the pump are used as the control variable.

The trimming of the watercraft described above can naturally automatically with the help of a computer be performed.

Claims (16)

1. A method of operating a water jet drive for watercraft, with a flow channel comprising an inlet, a pump and an outlet opening and with a nozzle assigned to the outlet opening, which can be changed in its effective cross section and can be controlled in the effective jet direction, characterized in that the cross section of the nozzle Regardless of the speed of the watercraft depending on the speed of the pump and the associated flow of water through the flow channel to a ratio of water flow to pump speed = constant. 2. The method according to claim 1, characterized in that the dynamic variable pdyn used in the region of constant cross-section and constant flow direction within the flow channel is used as a reference variable and according to the equation is regulated, where k is a constant determined as a function of the pump characteristic to the optimum pump efficiency and n is the pump speed. 3. The method according to claim 1, characterized in that uses the speed proportional to the throughput vx as the reference variable and the ratio of throughput to pump speed in accordance is kept constant, with "vx *" the flow speed at the measuring point "x" in the operating point optimum efficiency at the throughput "Q *" and the design speed "n *", and the speed "vx" the measured value at the current pump speed "n" and the throughput to be regulated mean "Q". 4. The method according to claims 1 to 3, characterized records that adjusting the size of the effective nozzles outlet cross section through at least two of each other independently adjustable, the outlet opening of the flow flaps or sliders assigned to the channel automatically or done manually. 5. The method according to claim 4, characterized in that for controlling the throughput / speed ratio Signals for the controlled variables pdynx and speed by one Calculator in the necessary adjustments of the control flaps effecting control signals are processed. 6. The method according to claim 4, characterized in that those for regulating the throughput / speed ratio required signals for manual control of the optimal nozzle cross-section can be displayed. 7. The method according to claims 1 to 6, characterized characterized in that the effective nozzle exit cross cut determining flaps or sliders additionally for a vertical deflection of the propulsion jet to trim the Watercraft are used.   8. The method according to claim 7, characterized in that for actuating the vertical deflection of the propulsion jet to trim the vehicle sensors to determine the Position of the watercraft about its transverse and / or longitudinal axis are used, whose signal to indicate the deviation from Setpoint and / or used to form control commands will. 9. The method according to claims 7 and 8, characterized characterized in that the trimming of the watercraft around his Transverse and / or longitudinal axis automatically using a Computer is carried out. 10. Water jet drive for carrying out the method according to claims 1 to 9, with a flow channel arranged in the forward direction on the watercraft with an inlet having an inlet at its front end and with a single-stage or multi-stage pump downstream of the inlet in the middle region of the flow channel for suction and accelerating water and with Einrich lines for changing the effective cross-section of a nozzle controllable in the effective jet direction at the jet outlet opening, characterized in that independently adjustable control flaps ( 20 , 21 ) are present, the one control flap being circular in shape and immediately around a in the nozzle body ( 19 ) mounted bearing ( 25 ') is pivotally arranged, and that the second control flap is straight and its position is adjustable by means of two independent adjustment devices mounted at both ends, d ate through it both at its front end towards the nozzle body or with respect to the rear end to the lower edge of the arc-shaped flap or with respect to both ends a gap for the emerging water jet is released. 11. Water jet drive according to claim 10, characterized in that the front edge ( 47 ) of the lower control flap ( 21 ) by means of the adjusting device ( 28 ) is mounted so that a bypass acting as an injector is formed, by which serves as a propellant jet Current of the amount of water conveyed by the pump is sucked in and accelerated an additional amount of water from below, in such a way that the amount of water leaving the nozzle increases, the average speed of which is reduced and thus an increase in thrust can be achieved at low driving speeds. 12. Water jet propulsion according to claims 10 and 11, characterized in that the lower flap ( 21 ) on the front bearing ( 27 ) with the gap ( 34 ) open is mounted such that a control of the water driving tool is also made possible in towing passive rudder is. 13. Water jet drive according to claims 10 to 12, characterized in that the lower flap ( 21 ) with respect to the front edge ( 47 ) in the region of the bearing ( 27 ) and on the rear edge ( 36 ) to the upper flap ( 20 ) of the water leading channel of the entire water jet drive is mounted so that it can be closed from the outlet side in such a way that flow through and / or damage to the inner pump parts is prevented when the drive is at a standstill. 14. Water jet drive according to claims 10 to 13, characterized in that the control flaps ( 20 , 21 ) are adjustably supported simultaneously and in the same direction (adjusting device 26 ). 15. Water jet drive according to claims 10 to 14, characterized in that the component (D) carrying the component is designed as a pivotable about a vertical axis ( 22 ) housing ( 19 ), the axis ( 22 ) of which is perpendicular or inclined to the vertical . 16. Water jet drive according to claims 10 to 15, characterized in that the housing ( 19 ) assigned to the upper flap ( 20 ) has a shape corresponding to the shape of the outlet cross section of the housing ( 19 ) and serves as the upper limit of the nozzle cross section that the lower flap ( 21 ) is flat and has two bearings ( 27, 32 ), and that the front bearing ( 27 ) of the lower flap ( 21 ) can be lowered via an adjusting device ( 28 ).