CN112329128B - Marine high-speed pump spraying hydraulic model with finely controlled blade load and design method thereof - Google Patents
Marine high-speed pump spraying hydraulic model with finely controlled blade load and design method thereof Download PDFInfo
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Abstract
The invention discloses a marine high-speed pump jet hydraulic model with finely controlled blade load and a design method thereof. The invention greatly increases the power density, introduces two technical measures of fine control of blade load distribution and reverse lateral inclination of stator and rotor blades, obviously improves the cavitation initial critical navigational speed, controls the unsteady force, and expands the pump jet to be applied to the propulsion of medium-high speed surface ships for the first time. The design philosophy shifts from low noise to anti-cavitation. The two new technical measures are also suitable for the design of submersible mechanical pump spraying and shaftless pump spraying, and the popularization and application of the pump spraying on the water surface and underwater propulsion systems can be quickly promoted after popularization and application.
Description
Technical Field
The invention relates to the technical field of ship propellers, in particular to a pump jet propeller which has excellent cavitation resistance and abnormal force inhibition and can be used for propelling a high-speed surface ship, and specifically relates to a high-speed pump jet with finely controlled blade load and reversely inclined stator and rotor blades and a design method thereof.
Background
Because of its obvious characteristics of low radiation noise and high critical navigational speed, pump jet propulsion (pumjet for short) is currently used in a large number of low noise submarine propulsion, such as "seawolf-level" submarines, "virginia-level" submarines and "minds of north wind" submarines. The invention patent 'a pump jet hydraulic model with a circumferentially asymmetric arrangement of front stators and a design method thereof (CN 105117564B, granted time: 2018.10)' discloses a pump jet for a low-noise propelling submersible, which is essentially characterized in that the line spectrum noise of the pump jet is reduced and the lateral steering force is improved in a circumferentially asymmetric arrangement structural form by regularly changing the pitch angle of front stator blades. The invention patent 'a design method of a shaftless drive type integrated motor pump jet propeller hydraulic model (CN 104462652B, authorization time: 2017.09)' discloses a design method of a hydraulic model in which shaftless pump jet is evolved after combination of shafted mechanical pump jet and an integrated motor, and the design method is used for propelling a submersible with the navigational speed of 16 knots. The invention patent of 'a front and rear stator type pump spraying hydraulic model for increasing lateral operating force and a design method (application number: 201810819277.5, 2018.07)', which is substantially examined, describes that the single-stage blade configuration is changed into the structural form of a front stator, a rotor and a rear stator, the lateral operating force is increased, the transient radiation noise during steering is reduced, and the invention is simultaneously suitable for mechanical pump spraying and shaftless pump spraying for propelling a submersible vehicle. The propulsion carriers of the design scheme are underwater vehicles, the designed navigational speed is lower than 18 sections, and the first principle is to reduce radiation noise and improve the critical navigational speed.
Although the existing pump jet (Pumpjet) is mainly applied to submarine and torpedo propulsion, the application occasion of the pump jet is not limited to underwater, for example, a U.S. destroyer USS Witek (DD-848, design navigational speed of 36.8 kn) with water displacement of 3400 tons in the second war adopts a double-shaft pump jet propulsion system, the construction quantity is up to 98, and the purpose is to demonstrate and verify the feasibility of pump jet propulsion of a high-speed surface ship. Although LCS of the main warship coastal battleship of the 21 st century army is completely changed to adopt a more appropriate water jet propeller (Waterjet, jet pump for short), the LCS cannot negate the application value of high-speed pump jet propulsion and the technical progress significance of the pump jet propulsion system which can be modified from the existing propeller shaft propulsion system by a small amount of involvement engineering.
The design expectation of the high-speed pump spraying from the underwater medium-low speed pump spraying to the water surface lies in that the cavitation resistance is mainly improved, the rapidity index is met while the advantage of low noise performance is kept as much as possible, and even the efficiency and the noise performance can be sacrificed to a certain extent. Because the displacement of the driving ship-protecting vessel is generally larger than that of a conventional submersible vehicle, and the propelling requirement of high navigation speed is added, the constraints of the pump jet on the overall size and the rotating speed can be slightly relaxed, the weight is also strictly limited, and in consideration of the situation that the propeller is replaced in situ, in order to inhibit the induced pulse pressure at the bottom of the ship, the radial direction of the pump jet must keep enough spacing distance with the bottom of the ship, and the radial dimension of the pump jet is constrained to be only slightly larger than that of the original propeller at most. Meanwhile, the rotating speed is controlled as far as possible in consideration of the noise reduction requirement, the power density of high-speed pump spraying for a surface ship is determined to be far larger than that of underwater pump spraying by the aid of the rotating speed and the noise reduction requirement, and the difficulty of anti-cavitation design is multiplied. Taking a surface ship of 8000 ton as an example, the original propeller diameter is 4.4 meters, the single-propeller power requirement is 26800kW when the designed navigational speed is 30 hours, if the rated navigational speed is taken as a design point, the design navigational speed is required to be realized without cavitation, and when the maximum pump jet diameter is relaxed to 4.6 meters, the single-pump power density reaches 1613kW/m 2 The upper limit of the power density of the modern 5-blade propeller reaching the navigational speed of 30 hours is 1500kW/m higher than that of the modern 5-blade propeller given by the KaMeWa company 2 About 7.6%. Even if the diameter of the pump spray is enlarged to 5 meters, the power density is about 2.7 times higher than that of the front stator type pump spray (the power is 3150kW, and the inlet diameter is 2.8 m) in the invention patent CN 105117564B, and beneficial factors of suppressing cavitation of the working depth are reduced, so that the difficulty of the anti-cavitation design of the blade profile of the pump spray is increased greatly, and a new technical measure is required to realize the expected design target.
One core content of successful design of the pump spray blade profile in the three invention patents is that a parameterized ternary reverse design method is adopted, three-dimensional geometric shape control of the blades is directly related to a blade load distribution rule, and high enough hydraulic efficiency can be ensured. Specifically, the blade load distribution rules adopt a three-section distribution rule along the axial flow direction and a quadratic circulation distribution rule along the radial direction. The three-section type refers to that the pressure coefficients of the blades from the blade root section to the blade tip section are distributed along the chord length direction and are all represented by spline curves formed by combining two sections of parabolas and a middle straight line, three-section type load distribution is called three-section type load distribution for short, and the three-section type load distribution is uniquely determined by 4 parameters of axial positions of inflection points at two ends of the straight line section, the slope of the straight line section and the load size of the starting point of the parabola at the position of a guide edge of the blade section. The control mode has the advantages of simple setting, visual appearance and capability of taking efficiency and cavitation performance requirements into consideration on the whole, such as the front-loading mode is favorable for synergy and the rear-loading mode is favorable for cavitation resistance; however, the method has the disadvantages that the local load distribution of the blade cannot be finely controlled, if desired, the convex parabola on the first section is changed into the concave parabola, so that the load distribution at the position close to the leading edge is reduced as much as possible, the small amount of local cavitation at the front edge of the blade is avoided, and the initial speed of the cavitation is further improved to the maximum extent. Design experience has shown that this design requirement is particularly desirable in high airspeed pump vane type designs.
In addition, in view of the fact that the rotating speed of the high-speed pump jet for the surface ship is usually slightly increased compared with that of the underwater pump jet, or the rotating speed is equivalent to that of the underwater pump jet, under the condition that the power density is greatly increased, in order to control the radiation noise of the pump jet as much as possible, particularly to control the low-frequency line spectrum noise, the abnormal force amplitude must be restrained as much as possible, so that new technical measures are introduced on the basis of the original effective technical measures, such as large lateral inclination of rotor blades, increase of the axial distance between the stator and rotor blades, increase of the number of the rotor blades and the like, and the measures which do not increase the processing, manufacturing and mounting difficulty as much as possible are required, so that the application effect of the pump jet on the medium-high-speed surface ship is maximized.
In the aspects of fine control of blade load and reverse skew design of stator and rotor blades, related documents published in China at present hardly report, and the retrieval result in the Chinese knowledge network is zero. Furthermore, in the Chinese patent network, retrieval is carried out by respectively using 'blade load fine control' and 'reverse lateral inclination of stator and rotor blades' as keywords, and related patents are not retrieved; in addition, in the international patent web, when searching for "Blade loads controlling precision" as a keyword, only 2 U.S. patents are directly related. One is "Wind turbine blade and method for controlling the load on a blade" (publication No. US2010/0215493 A1, 2010.8), which describes: the actuator arranged at the tail edge of the blade is driven by sensing the signal of the force sensor arranged on the blade, so that the aim of adjusting the pressure load of the blade is fulfilled; the other is ' precision loading blade and method for making same ' (accurate loading blade and synchronous realization method thereof, publication number: US5040030, 1991.8) ', which discloses a self-cleaning blade capable of accurately loading and sealing an antistatic surface and having certain rigidity and thickness, both inventions are essentially different from the invention described in the design stage of fine control of load distribution; on the basis, when a keyword of Rotor and Stator rotating blades is used for retrieval in an international patent network, retrieval patents mainly focus on the aspect of motor design, only two U.S. patents are related to the connection, one is a Stator for fan (a fan Stator, publication number: US6142733, 2000.12), and the patent discloses a fan assembly comprising a static flow guide Stator blade, a support ring and a rotating fan blade, and is mainly characterized in that one surface of the Stator blade is a plane, and the other surface of the Stator blade is a curved surface; the other one is High efficiency, low noise, axial fan assembly, which discloses a fan with a heat exchanger stator flow passage part, and the two inventions are not directly related to the technical measures of leading stator and rotor blade reverse sideslip in the design stage.
From the research background and the current application situation, aiming at two specific application requirements of cavitation resistance and noise control of high-speed pump jet, the invention introduces a blade load fine control and stator and rotor blade reverse side inclination design method, helps to simultaneously realize cavitation resistance design and unsteady force control of high-speed pump jet, clears technical obstacles for pump jet medium-high speed surface ship application, is a direct expansion of the original submersible pump jet hydraulic model design method, has creativity, can effectively fill up the defects of the application field in China, and promotes the independent research, development and popularization and application of medium-high speed surface ship pump jet propulsion.
Disclosure of Invention
The invention aims to expand pump jet from underwater low-and-medium-speed submersible vehicle propulsion to medium-and-high-speed water surface ship propulsion, and on the basis of design of a submersible vehicle pump jet hydraulic model, by greatly increasing power density, and introducing the characteristics of fine control of blade load distribution and reverse side inclination design of stator and rotor blades, the anti-cavitation performance is improved, particularly the generation of local cavitation is inhibited, the abnormal force is controlled, and then the low-frequency line spectrum noise is controlled, so that the invention can better adapt to the tail non-uniform wake field of the water surface ship under the conditions of medium-and-low-speed navigation and small-work sinking depth, and maintain the performance advantages of strong anti-cavitation capability and low noise of the pump jet.
In order to achieve the aim, the invention designs a high-speed pump jet propeller hydraulic model for a ship with stator and rotor blades with reverse side inclined surfaces, which is used for finely controlling the blade load distribution, and is characterized in that: the device comprises a guide pipe, wherein a stator and a rotor which are coaxial are arranged in the guide pipe, the stator is arranged in front, and the rotor is arranged in back; the stator comprises a stator blade and a stator hub, the stator blade is fixed on the stator hub, and a stator blade tip is fixed on the inner wall surface of the guide pipe; the rotor comprises a rotor blade and a rotor hub, the rotor blade is fixed on the rotor hub, and equidistant blade top gaps are reserved between the blade tip end surface of the rotor blade and the inner wall surface of the guide pipe; the stator blades and the rotor blades are circumferentially and symmetrically arranged on the hub, the small front sides of the stator blades are inclined, and the large rear sides of the rotor blades are inclined; the blade profiles of the stator blade and the rotor blade are obtained by a parametric ternary reverse design method, the load distribution of the blade section of the stator blade adopts a three-section control rule, and the load distribution of the blade section of the rotor blade adopts a B spline fine control rule.
Preferably, the stator blade has a blade number of 11 blades, and the rotor blade has a blade number of 7 or 9 blades.
Preferably, the ratio of the blade top clearance of the rotor impeller blade to the rotor diameter is 2-5 per mill according to the machining precision.
Preferably, the front side inclination degree of the stator blade is 20-40%, and the rear side inclination degree of the rotor blade is 50-60%.
Further preferably, the stator blade and the rotor blade increase the side bevel angle according to a given rule from the blade root to the blade tip section, and the mathematical expression of the side bevel angles at the sections with different radii is as follows:
wherein, theta smax Is the blade tip section side bevel angle, used to describe the side bevel angle of the stator and rotor blades; r is a radical of hydrogen h Is the hub radius, R is the stator or rotor radius, R is any cross-sectional radius on the blade, θ s Is the side bevel at radius r cross section. The lateral inclination degree is the percentage of the ratio of the lateral inclination angle of the blade tip section to the circumferential included angle of two adjacent blades.
Preferably, both the stator and rotor blades use a NACA16 airfoil thickness profile.
Preferably, the cross-sectional profile formed by the inner and outer wall surfaces of the conduit is an airfoil.
The invention discloses a design method of a hydraulic model of a high-speed pump jet propeller for a ship with stator and rotor blades with reverse side inclined surfaces and blades with finely controlled blade load distribution, which comprises the following steps:
firstly), carrying out model selection design on hydraulic parameters of a pump fluid channel according to design requirements;
secondly), determining two-dimensional axial plane projection geometry of the pump spraying preposed stator, the postpositive rotor and the inner and outer wall surfaces of the conduit;
thirdly) determining the three-dimensional geometric shapes of the stator and the rotor by adopting a parameterized ternary reverse design method according to results obtained in the first step and the second step; rotating the two-dimensional axial plane projection geometry of the catheter along the axial direction according to the results obtained in the first step) and the second step to obtain the three-dimensional geometry of the catheter;
fourthly) adopting a computational fluid mechanics method to calculate the hydrodynamic performance and the cavitation performance of the pump jet under the conditions of the designed navigational speed, the designed rotating speed and the designed stern wake current of the model obtained in the third) step, and judging whether the axial thrust, the consumed power and the cavitation performance of the pump jet meet the design requirements or not: if yes, the next step is carried out; if not, returning to the step two) to modify the corresponding two-dimensional axial plane projection geometry, adjusting the blade load distribution curve of the stator and the rotor in the ternary reverse design process, and redesigning the three-dimensional geometric shapes of the stator and the rotor;
fifthly), leading in small front side inclination of the stator blade and large rear side inclination of the rotor blade: the ratio of the side oblique angle of the blade tip section of the stator blade to the included angle between the adjacent blades of the stator is 20-40%, the ratio of the side oblique angle of the blade tip section of the rotor blade to the included angle between the adjacent blades of the rotor is 50-60%, and the side oblique angles of the blade sections of the stator blade and the rotor blade at different radiuses are increased according to a linear rule from the blade root to the blade tip section;
sixthly), performing transient calculation on the model obtained in the step five) by adopting a computational fluid mechanics method, and judging whether the ratio of the axial unsteady force to the average thrust of the pump jet is less than 30% under the conditions of designed navigational speed, rotating speed and stern wake flow: if yes, the next step is carried out; if not, returning to the step five), increasing the reverse lateral inclination degree of the stator blade and the rotor blade, and if necessary, increasing the axial distance between the stator and the rotor;
and seventhly) determining a high-speed pump jet propeller hydraulic model for the ship with the stator and rotor blades being controlled by the blade load distribution in a fine manner and being inclined towards the reverse side.
Preferably, said steps one) to three) are the same as those carried out in patent CN 105117564B, the only difference being: and step three), in the process of determining the rotor blade profile by applying a parameterized ternary reverse design method, the blade load distribution rule is changed into a B spline fine control rule from a three-stage control rule.
Further preferably, when the rotor blade load distribution adopts a B spline fine control rule, the B spline near the leading edge suggests a preferred concave parabolic shape, and the leading edge load of the blade section is reduced as much as possible.
Preferably, the implementation processes of steady-state calculation and transient calculation of the computational fluid dynamics method in the fourth step) and the sixth step) are the same as those in the patent CN 105117564B.
The invention has the beneficial effects that: on the basis of the design of a pump spraying hydraulic model of a medium-low speed submersible, after power density is obviously increased, the characteristics of fine control of blade load distribution and reverse lateral inclination design of stator and rotor blades are introduced, the pump spraying anti-cavitation performance is improved, the unsteady force is controlled, and the high-speed pump spraying hydraulic model suitable for 8000-ton water surface ship propulsion is designed. The primary principle of design is to shift from low noise to anti-cavitation. The number of the front stator blades in the pump spraying hydraulic model is 11, the number of the rear rotor blades is 7 or 9, and the cross section profile of the conduit is an airfoil profile. Both stator and rotor blades employ NACA16 airfoil thickness distribution characteristics. The stator blades have a small forward skew, and the rotor blades have a large aft skew feature. The design pump is sprayed under the conditions of 30 sections of rated navigational speed, 165rpm of rated rotational speed and the wake flow behind a ship, the consumed power of a single pump is less than 26MW, the generated thrust is 1095kN, the hydraulic efficiency is 0.834, the total thrust efficiency of a double-pump propulsion system is 0.654, the cavitation-free primary navigational speed is higher than 26 sections, the ratio of the first-order axial unsteady force to the average thrust is less than 20 percent, and the rapidity and cavitation design requirements are met. The two new technical measures adopted in the design scheme are also suitable for the design of mechanical pump spraying and shaftless pump spraying for propelling the underwater vehicle, in particular to application objects with particularly strict requirements on anti-cavitation performance, and the popularization and application of the pump spraying on the medium-high speed surface ship propulsion system can be quickly promoted after the technical measures are popularized and applied.
Drawings
FIG. 1 is a three-dimensional geometry of a marine high-speed pump water jet model with fine control of blade loading according to an embodiment of the invention;
FIG. 2 is a structural arrangement of a high-speed pump jet mounted on the stern of a biaxial shaft for a ship with stator and rotor blades having finely controlled blade load distribution according to an embodiment of the present invention;
FIG. 3 is a three-stage load control curve adopted in designing the high-speed pump-spraying stator blade profile for the ship with the stator and rotor blades inclined to the opposite sides for finely controlling the blade load distribution according to the embodiment of the invention;
FIG. 4 is a B-spline load fine control curve adopted in designing a high-speed pump-spraying rotor blade profile for a stator and rotor blade reverse-side inclined surface ship for fine control of blade load distribution according to an embodiment of the present invention;
FIG. 5 is a comparison graph of cavitation performance of a three-stage load control curve and a B-spline load fine control curve at a designed navigational speed when designing a high-speed pump-jet rotor profile for a marine surface with a reverse slope of stator and rotor blades for fine control of blade load distribution according to an embodiment of the present invention;
FIG. 6 is a flow chart of the design of a marine high-speed pump water injection model with fine control of blade load according to the embodiment of the invention.
Detailed Description
The technical solutions (including the preferred technical solutions) of the present invention are further described in detail by referring to fig. 1 to fig. 6 and some alternative embodiments of the present invention, and any technical features and any technical solutions in the present embodiment do not limit the protection scope of the present invention.
The flow chart of the marine high-speed pump water spraying model design method for finely controlling the blade load designed by the invention is shown in figure 6,
step S1, carrying out model selection design on hydraulic parameters of a pump fluid channel according to design requirements, and determining 5 parameters of the lift, the flow, the outlet area, the specific rotating speed and the suction inlet specific rotating speed of a pump blade cascade channel.
And S2, determining two-dimensional axial plane projection geometry of the pump spraying preposed stator, the postpositioned rotor and the inner and outer wall surfaces of the guide pipe, wherein the two-dimensional axial plane projection geometry comprises axial plane projections of the guide edge and the trailing edge of the blade, the cross sections of the blade tip and the blade root and the inner and outer wall surfaces of the guide pipe.
S3, determining the three-dimensional geometric shapes of the stator and the rotor by adopting a parameterized ternary reverse design method according to results obtained in the steps S1 and S2; and (3) rotating the two-dimensional axial plane projection geometry of the catheter along the axial direction according to the results obtained in the step (S1) and the step (S2) to obtain the three-dimensional geometry of the catheter.
Steps S1 to S3 are the same as those of CN 105117564B. When confirming stator and rotor blade's blade profile, stator blade is along with the limit and is adopted increasing gradually type annular distribution, and blade load adopts syllogic load distribution law, specifically is: the blade root section adopts a middle-load type load distribution, and the blade tip section adopts a front-load type load distribution, as shown in fig. 3; the rotor blade is distributed along the edge by using quadratic circular quantity, and the blade load distribution adopts a B spline fine load control rule, as shown in FIG. 4.
Wherein, the three-stage type load distribution control rule is as follows: the load distribution curve consists of a first section of outward convex parabolic curve, a middle section of straight line and a tail section of outward convex parabolic curve, wherein the middle section of straight line is controlled by the given axial positions and slopes of the front end point and the rear end point, and the axial positions of the front end point and the rear end point can approach to the same point; when the slope of the straight line is zero, the load distribution rule is called medium-load type load distribution, when the slope of the straight line is negative, the load distribution rule is called front-load type load distribution, and otherwise, when the slope of the straight line is positive, the load distribution rule is called rear-load type load distribution. The B spline fine load control rule is as follows: the load distribution curve is composed of a first section of multi-time spline curve, a middle section of straight line and a tail section of multi-time spline curve, and the middle section of straight line is still controlled by the given axial positions and slopes of the front end point and the rear end point.
And S4, adopting a computational fluid dynamics method to stably calculate the hydrodynamic performance and the cavitation performance of the pump jet of the model obtained in the step S3 under the conditions of the designed navigational speed, the designed rotational speed and the designed stern wake current, and judging whether the axial thrust, the consumed power and the cavitation performance of the pump jet meet the design requirements or not: if yes, the next step is carried out; if not, returning to the step S2 to modify the corresponding two-dimensional axial plane projection geometry, adjusting the blade load distribution curves of the stator and the rotor in the ternary reverse design process, and redesigning the three-dimensional geometric shapes of the stator and the rotor;
when the pump jet thrust and the power are checked, if the thrust is insufficient and the power is too high, the axial positions of the leading edge and the trailing edge of the rotor blade can be moved backwards; when cavitation performance is checked, if local small-amount cavitation occurs at the position, close to the leading edge, of the suction surface of the rotor blade, the load value of the blade section at the position, close to the leading edge, is reduced, and the concave spline curve at the first section of the B spline fine load control curve is moved downwards. As shown in fig. 5, when the rotor blade profile is designed, after the upper convex parabola profile curve of the first section of the three-section load control curve is changed into the lower concave spline curve of the first section of the B-spline fine load control curve, two local small cavitations at the near-leading edge of the suction surface of the rotor blade at the designed navigational speed are significantly inhibited.
Step S5, introducing the characteristics of small front side inclination of the stator blade and large rear side inclination of the rotor blade: the ratio of the side oblique angle of the blade tip section of the stator blade to the included angle between the adjacent blades of the stator is 20-40%, the ratio of the side oblique angle of the blade tip section of the rotor blade to the included angle between the adjacent blades of the rotor is 50-60%, and the side oblique angles of the blade sections of the stator blade and the rotor blade at different radiuses from the blade root to the blade tip section are increased according to a linear rule. The front and rear lateral inclinations refer to the lateral inclination direction which is the same as or opposite to the circumferential rotating direction of the rotor blade; the small and large lateral inclinations refer to the ratio of the lateral inclination angle to the included angle between the adjacent blades which is less than or not less than 50%. The mathematical expression for the side bevel angles at sections of different radii is:
wherein, theta smax In the embodiment, the number of the stator blades is 11, the side oblique angle of the blade tip section is 10 degrees, the front side inclination towards the rotation direction of the rotor is 30%, the number of the rotor blades is 7, the side oblique angle of the blade tip section is 30 degrees, and the back side inclination towards the rotation direction of the rotor is 58%; r is a radical of hydrogen h Is the radius of the hub of the stator and the rotor, R is the radius of the stator and the rotor, R is the radius of any section on the blade, theta s Is the side bevel at radius r cross section.
S6, adopting a computational fluid mechanics method to transiently calculate the unsteady force of the pump jet of the model obtained in the step S5 under the conditions of designing the navigational speed, the rotating speed and the stern wake flow, and judging whether the ratio of the axial unsteady force of the pump jet to the average thrust is less than 30 percent or not: if yes, carrying out the next step; if not, returning to the step S5 to increase the reverse side inclination degree of the stator blade and the rotor blade, and increasing the axial distance between the stator and the rotor when the time still exceeds the standard.
The implementation method for transient CFD calculation of unsteady force is the same as the sixth step in patent CN 105117564B).
And S7, determining the hydraulic model of the high-speed pump jet propeller for the ship with the stator and rotor blades with the reverse side inclined surfaces and the rotor blades with the finely controlled blade load distribution. The finally obtained pump spraying hydraulic model is shown in figure 1, the double-pump spraying replaces double controllable-pitch propellers, the structural arrangement when the double-pump spraying is installed at the stern is shown in figure 2, a traditional 'beauty frame' is omitted, pump spraying inflow is facilitated, a fixed connecting guide pipe and a sword-shaped support at the bottom of a ship are added, and the structural safety is guaranteed.
As shown in fig. 1, the high-speed pump jet propeller hydraulic model for the ship with the stator and rotor blades with the reverse inclined sides and the finely controlled blade load distribution comprises a guide pipe, wherein a stator and a rotor which are coaxial are arranged in the guide pipe, the stator is arranged in the front, and the rotor is arranged in the rear; the stator comprises a stator blade 1 and a stator hub 2, the stator blade 1 is fixed on the stator hub 2, and a stator blade tip is fixed on the inner wall surface of the guide pipe 5; the rotor comprises a rotor blade 3 and a rotor hub 4, the rotor blade 3 is fixed on the rotor hub 4, and equidistant blade top gaps are reserved between the end surface of the blade tip of the rotor blade and the inner wall surface of the guide pipe 5; the stator blades and the rotor blades are circumferentially and symmetrically arranged on the hub, the small front side of each stator blade 1 is inclined, and the large rear side of each rotor blade 3 is inclined; the blade profiles of the stator blade and the rotor blade are obtained by a parametric ternary reverse design method, the load distribution of the blade section of the stator blade adopts a three-section control rule, and the load distribution of the blade section of the rotor blade adopts a B spline fine control rule.
When the original propeller is replaced by pump spraying, the structure of a propeller shaft system is kept unchanged as much as possible, so that the involvement engineering is minimized. As shown in fig. 2, the diameter of the propeller shaft 6 at the tail end of the stern shaft is adaptively increased because the hub diameter of the pump injection stator is larger than that of the propeller hub; because the cavitation initial navigational speed of the original propeller propulsion system is lower than the cruising navigational speed by 18 knots, the pump jet propulsion system is supposed to realize that the cavitation-free critical navigational speed is higher than 26 knots, even the cavitation-free generation is expected to be realized within the range of the full navigational speed of 30 knots, so that the outflow speed sprayed by a high-navigational speed pump is obviously higher than the propeller at the cruising navigational speed, and the cavitation of a vane is generated in the guide edge area of the control surface 7, which inevitably influences the realization of the anti-cavitation performance of the whole propulsion system, therefore, the design of the geometric adjustment of the control surface is proposed, for example, a twisted rudder or a step curved surface rudder is adopted, and the specific effect is elaborated in the next invention application.
Preferably, the tip clearance between the rotor blade 3 and the inner wall surface of the duct 5 is 3 ‰ of the rotor diameter.
Preferably, the front oblique angle of each stator blade is smaller than half of the included angle between two adjacent stator blades 1, and the rear oblique angle of each rotor blade is larger than half of the included angle between two adjacent rotor blades 3. The front side diagonal fingers are in the diagonal direction opposite to the rotation direction of the rotor blades, whereas the rear side diagonal fingers are in the opposite direction to the rotation direction of the rotor blades. The side bevel angle of the stator blade 1 and the rotor blade 3 increases according to a given rule from the blade root to the blade tip section, and the mathematical expression of the side bevel angles at the sections with different radiuses is as follows:
wherein, theta smax Is the blade tip section side cant angle, used to describe the side cant angle of a stator blade or rotor blade; r is h Is the stator or rotor hub radius, R is the stator or rotor radius, R is any cross-sectional radius on the stator or rotor blade, θ s Is the side bevel at radius r cross section.
Preferably, both the stator and rotor blades use a NACA16 airfoil thickness profile.
Preferably, the cross-sectional profiles of the inner and outer wall surfaces of the duct 5 are airfoil-shaped.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.
Those not described in detail in this specification are well within the skill of the art.
Claims (10)
1. The utility model provides a marine high-speed pump of meticulous control of blade load spouts which characterized in that: the device comprises a guide pipe, wherein a stator and a rotor which are coaxial are arranged in the guide pipe, the stator is arranged in front, and the rotor is arranged in back; the stator comprises stator blades and a stator hub, the stator blades are fixedly arranged on the stator hub, and blade tips of the stator blades are fixed on the inner wall surface of the guide pipe; the rotor comprises a rotor blade and a rotor hub, the rotor blade is fixed on the rotor hub, and equidistant blade top gaps are formed between the end surface of the blade tip of the rotor blade and the inner wall surface of the guide pipe; the stator blades and the rotor blades are circumferentially and symmetrically arranged on the hub, the small front sides of the stator blades are inclined, and the large rear sides of the rotor blades are inclined; and acquiring the blade profiles of the stator blade and the rotor blade by a parametric ternary reverse design method, wherein the load distribution of the blade section of the stator blade is controlled in a three-section mode, and the load distribution of the blade section of the rotor blade is finely controlled by adopting a B spline.
2. Marine high-speed pump shooting with fine control of blade load according to claim 1, characterized in that: the number of the stator blades is 11, and the number of the rotor blades is 7 or 9.
3. Marine high-speed pump shooting with fine control of blade load according to claim 1, characterized in that: a blade top gap is formed between the blade tip section of the rotor blade and the inner wall surface of the guide pipe, and the ratio of the blade top gap to the diameter of the rotor is 2-5 per mill.
4. The marine high-speed pump nozzle with fine blade load control according to any one of claims 1 to 3, wherein: the small front skew of the stator blade means that the side skew angle of the stator blade is smaller than half of the included angle between the adjacent stator blades, the skew direction is the same as the rotating direction of the rotor blade, the large rear skew of the rotor blade means that the side skew angle of the rotor blade is larger than or equal to half of the included angle between the adjacent rotor blades and smaller than or equal to the included angle between the rotor blades, and the skew direction is opposite to the rotating direction of the rotor blades.
5. The marine high-speed pump nozzle with fine blade load control according to claim 4, wherein: the side oblique angles of the stator blade from the blade root section to the different-radius sections of the blade tip section are increased according to a linear rule; the side bevel angle of the rotor blade increases according to a linear rule from the blade root section to the blade tip section at sections with different radii.
6. The marine high-speed pump nozzle with fine blade load control according to claim 1, characterized in that: the stator blade and the rotor blade are distributed in the thickness of an NACA16 airfoil, and the airfoil is formed by the section profiles of the inner wall surface and the outer wall surface of the guide pipe.
7. The design method of the marine high-speed pump water spraying hydraulic model with finely controlled blade load comprises the following steps:
firstly), the model selection design of hydraulic parameters of a pump fluid channel;
secondly), determining two-dimensional axial plane projection geometry of the pump spraying preposed stator, the postpositive rotor and the inner and outer wall surfaces of the conduit;
thirdly), determining the three-dimensional geometric shapes of the stator and the rotor by adopting a parameterized ternary reverse design method according to the results obtained in the first step and the second step; rotating the two-dimensional axial plane projection geometry of the catheter along the axial direction according to the results obtained in the first step) and the second step to obtain the three-dimensional geometry of the catheter;
fourthly) adopting a computational fluid mechanics method to calculate the hydrodynamic performance and the cavitation performance of the pump jet under the conditions of designed navigational speed, rotating speed and wake current of the model obtained in the third step), and judging whether the axial thrust, the consumed power and the cavitation performance of the pump jet meet the design requirements or not: if yes, carrying out the next step; if not, returning to the step two) to modify the corresponding two-dimensional axial plane projection geometry, adjusting the blade load distribution rule of the stator and the rotor in the ternary reverse design process, and redesigning the three-dimensional geometric shapes of the stator and the rotor;
fifthly), leading in small front side inclination of the stator blade and large rear side inclination of the rotor blade: the ratio of the side oblique angle of the blade tip section of the stator blade to the included angle between the adjacent blades of the stator is 20-40%, the ratio of the side oblique angle of the blade tip section of the rotor blade to the included angle between the adjacent blades of the rotor is 50-60%, and the side oblique angles of the blade sections of the stator blade and the rotor blade at different radiuses from the blade root to the blade tip section are increased according to a linear rule;
sixthly) adopting a computational fluid mechanics method to calculate the unsteady force of the pump jet of the model obtained in the step five) under the conditions of designing the navigational speed, the rotating speed and the stern wake flow, and judging whether the ratio of the axial unsteady force of the pump jet to the average thrust is less than 30 percent or not: if yes, the next step is carried out; if not, returning to the step five), firstly, equally dividing the original reverse side inclination degree into intervals of 10 equal parts, and increasing the reverse side inclination degrees of the stator blade and the rotor blade by taking 1 equal part of the intervals each time; then, 10 equal parts of the axial distance of the original stator and rotor are used as intervals, and the axial distance between the stator and the rotor is increased by taking 1 equal part of the intervals as amplitude each time until the unsteady force meets the requirement of 30% of a preset limit value;
and seventhly) assembling the three-dimensional geometry of the guide pipe determined in the step three) and the three-dimensional geometry of the pump spray blade profile determined in the step six), namely determining a marine high-speed pump spray hydraulic model with finely controlled blade load.
8. The design method of the marine high-speed pump water injection model with the finely controlled blade load according to claim 7 is characterized in that: when the three-dimensional geometric shapes of the stator and the rotor blade are designed in the third step): the trailing edges of the stator blades are distributed in an increasing type annular quantity mode, the blade loads are distributed in a three-section type load distribution mode, the blade root sections are distributed in a medium-load type load mode, and the blade tip sections are distributed in a front-load type load mode; the rotor blade is distributed along the edge by using quadratic circle quantity, and the blade load distribution is controlled by adopting B-spline fine load.
9. The marine high-speed pump water-jet force model design method for the fine blade load control according to claim 7: when the cavitation performance is checked through steady-state calculation in the step four), if local cavitation occurs at the leading edge of the suction surface of the rotor blade, the load value of the blade section close to the leading edge is reduced by taking 5 equal parts of the load value at the original leading edge as intervals and 1 equal part of the intervals as amplitude every time, and the concave parabolic profile curve at the first section of the B-spline fine load control curve is moved downwards; the local cavitation refers to the ratio of the cavitation area at the leading edge of the suction surface of the rotor blade to the disc area being less than 5%.
10. The design method of the marine high-speed pump water injection hydraulic model with the finely controlled blade load according to claim 7 comprises the following steps: in the sixth step), returning to the second step), modifying the corresponding two-dimensional axial plane projection geometry, adjusting the blade load distribution rule of the stator and the rotor in the ternary reverse design process, and redesigning the three-dimensional geometric shapes of the stator and the rotor comprises the following steps: when pump jet thrust and power are checked, if the thrust is smaller than a design value and the power is larger than the design value, 5 equal parts of the axial distance from the trailing edge of the original rotor blade to the outlet of the guide pipe are used as intervals, and the axial positions of the leading edge and the trailing edge of the rotor blade are moved backwards by taking 1 equal part of the interval as amplitude each time; when the cavitation performance is checked, if local small-amount cavitation with the cavitation area ratio smaller than 5% occurs at the position, close to the leading edge, of the suction surface of the rotor blade, the load value of the blade section close to the leading edge is reduced by taking 5 equal parts of the load value at the original leading edge as intervals and taking 1 equal part of the intervals as amplitude every time, and the concave spline curve at the first section of the B-spline fine load control curve is moved downwards.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0742509A (en) * | 1993-07-29 | 1995-02-10 | Mitsubishi Heavy Ind Ltd | Movable blade control device for ciculating water pump |
| WO2011071420A1 (en) * | 2009-12-09 | 2011-06-16 | Открытое Акционерное Общество "Силовые Машины - Зтл, Лмз, Электросила, Энергомашэкспорт" (Оао "Силовые Машины") | Vane apparatus of an impeller of a radial/axial hydroturbine |
| CN105117564A (en) * | 2015-09-18 | 2015-12-02 | 中国人民解放军海军工程大学 | Pumpjetpropulsor hydraulic model with front stators circumferentially and asymmetrically arranged and design method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7284495B2 (en) * | 2005-04-04 | 2007-10-23 | Seiford Sr Donald S | Shaftless radial vane rotary device and a marine propulsion system using the device |
| US7442007B2 (en) * | 2005-06-02 | 2008-10-28 | Pratt & Whitney Canada Corp. | Angled blade firtree retaining system |
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2020
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0742509A (en) * | 1993-07-29 | 1995-02-10 | Mitsubishi Heavy Ind Ltd | Movable blade control device for ciculating water pump |
| WO2011071420A1 (en) * | 2009-12-09 | 2011-06-16 | Открытое Акционерное Общество "Силовые Машины - Зтл, Лмз, Электросила, Энергомашэкспорт" (Оао "Силовые Машины") | Vane apparatus of an impeller of a radial/axial hydroturbine |
| CN105117564A (en) * | 2015-09-18 | 2015-12-02 | 中国人民解放军海军工程大学 | Pumpjetpropulsor hydraulic model with front stators circumferentially and asymmetrically arranged and design method thereof |
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