A full parametric pump-jet propulsor design method

Abstract

The application provides a full-parameter pump-jet propeller design method, and specifically comprises the following steps: S1: determining characteristic parameters of a stator airfoil, a rotor airfoil and a duct airfoil, including chord length, maximum camber, maximum thickness, leading edge radius and trailing edge radius; a longitudinal inclination, a side inclination and a pitch corresponding to an airfoil profile of the rotor airfoil at different radial positions; a rotation angle of the stator; a relative distance between the rotor and the stator; S2: establishing an airfoil profile model of the stator airfoil, the rotor airfoil and the duct airfoil at different radial positions; S3: using a three-dimensional modeling software to establish a rotor model, including performing curve fitting on an original parameter curve of the rotor airfoil according to an F-spline curve fitting principle to obtain a corresponding rotor airfoil fitting parameter curve, and obtaining a rotor airfoil surface model by integration according to the rotor airfoil fitting parameter curve; and S4: establishing a stator model and a duct model. The application solves the problem that the existing propeller modeling method cannot realize flexible control of parameters.

Description

Technical Field

[0001] This invention relates to the field of marine propulsion technology, and more particularly to a fully parameterized pump-jet propulsion design method. Background Technology

[0002] Current methods for propeller modeling typically require manually creating a 3D solid propeller model. For example, Zhang Hongwei et al. proposed a program design method for calculating propeller shape point coordinates, manually importing data files into ProE software for solid modeling, but did not study a rapid modeling method after importing shape points into the software; Wu Lihong et al. used MATLAB to calculate the spatial coordinate points of the propeller blades and imported the spatial coordinate points in one go through ProE, but still needed to manually create a 3D solid propeller; Liu Kanle et al. used a combination of PropCAD and Rhino software to study a rapid method for propellers, but ultimately still needed to manually create the 3D propeller model.

[0003] Pump-jet propulsion is a component-combined propulsion device consisting of a rotor, stator, and duct. Manually creating a 3D model makes it difficult to achieve flexible control over the shape of the duct, stator, stator rotation angle, relative distance between the stator and rotor, and rotor shape. Therefore, it is also impossible to establish the relationship between the geometric features of pump-jet propulsion and its performance. Summary of the Invention

[0004] To address the technical problems of existing propeller modeling methods, a fully parameterized pump-jet propulsion design method is provided. By establishing a fully parameterized pump-jet propulsion model, the model can be flexibly controlled when studying the relationship between the geometric features and performance of the pump-jet propulsion, ensuring sufficient optimization design sample space, guaranteeing the high efficiency of pump-jet propulsion performance prediction and optimization, and improving the pump-jet propulsion performance optimization system.

[0005] The technical means employed in this invention are as follows:

[0006] A fully parameterized pump-jet propulsion design method specifically includes the following steps:

[0007] S1: Select the stator airfoil, rotor airfoil, and duct airfoil of the pump-jet propulsion system as needed, and determine the following parameters:

[0008] Based on the camber and thickness distribution lines of the stator airfoil, rotor airfoil, and duct airfoil in different radial directions, determine the characteristic parameters of the airfoil profile: chord length, maximum camber, maximum thickness, leading edge radius, and trailing edge radius;

[0009] Tilting, skew, and pitch corresponding to airfoil profiles at different radial directions of the rotor airfoil;

[0010] rotational angle of the stator;

[0011] relative distance between the rotor and the stator;

[0012] S2: using a three-dimensional modeling software, a profile model of the stator airfoil, the rotor airfoil and the duct airfoil at different radial positions is established

[0013] According to the camber distribution line, the thickness distribution line and the characteristic parameters, a profile model of the stator airfoil, the rotor airfoil and the duct airfoil at different radial positions is established by using the characteristic parameter description method respectively;

[0014] S3: using a three-dimensional modeling software, a rotor model is established

[0015] According to the chord length, the maximum camber, the maximum thickness, the pitch, the skew and the twist of the profile model of the rotor airfoil at different radial positions, the original parameter curves of the rotor airfoil are obtained, including the maximum chord length curve, the maximum thickness curve, the maximum camber curve, the twist curve, the pitch curve and the skew curve;

[0016] According to the F-spline curve fitting principle, each original parameter curve of the rotor airfoil is curve fitted to obtain the corresponding fitting parameter curve of the rotor airfoil, and in the curve fitting process, the point variance of the fitting parameter curve of the rotor airfoil and the original parameter curve of the rotor airfoil is ensured to be minimum, and the rotor airfoil surface model is obtained by integrating the fitting parameter curve of the rotor airfoil;

[0017] In the three-dimensional modeling software, the rotor airfoil surface model is connected with the hub model by Boolean operation to form a closed rotor model;

[0018] S4: according to the characteristic parameters corresponding to the profile model of the stator airfoil and the duct airfoil at different radial positions, a stator model and a duct model are established by using a three-dimensional modeling software, and the stator model, the duct model and the rotor model are connected to form a complete pump-jet propeller model according to the rotational angle of the stator and the relative distance between the rotor and the stator determined in step S1.

[0019] Further, the rotor model includes a plurality of rotor airfoil surface models, and the other rotor airfoil surface models are obtained by copying and rotating one rotor airfoil surface model in the three-dimensional modeling software.

[0020] Further, the three-dimensional modeling software used is CAESES.

[0021] Further, the method further comprises a step S5 of parameterizing the pump-jet propeller model by adjusting the characteristic parameters corresponding to the airfoil profile models of the stator airfoil and the duct airfoil at different radial positions, the chord length, the maximum camber, the maximum thickness, the leading edge radius, the trailing edge radius, the dihedral, the side-slip and the pitch of the rotor airfoil at different radial positions, the rotation angle of the stator and the relative distance between the rotor and the stator.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] The full-parameter pump-jet propeller design method provided by the present application can achieve flexible control over the duct shape, the stator shape, the stator rotation angle, the relative distance between the stator and the rotor and the rotor shape, and can establish a method of expressing the shape of a solid model by characteristic parameters, convert the geometric information of the solid model into characteristic parameters, and accurately express the solid model by defining the characteristic parameters. The solid model can be changed by changing the characteristic parameters, so that the performance of the pump-jet propeller can be optimized. The parametric modeling of the pump-jet propeller can better establish the relationship between the geometric characteristics of the pump-jet propeller and the performance of the pump-jet propeller.

[0024] Based on the above reasons, the present application can be widely used in the field of ship propulsion. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0026] Figure 1 The figure is a schematic diagram of the airfoil profile of the pump-jet propeller stator airfoil, the rotor airfoil and the duct airfoil according to the present application.

[0027] Figure 2 The figure is a mapping relationship between the rotor airfoil parameter curve and the rotor model in the full-parameter pump-jet propeller design method according to the present application.

[0028] Figure 3 The figure is a schematic diagram of the pump-jet propeller model obtained by using the full-parameter pump-jet propeller design method according to the present application. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] like Figures 1-3 As shown, since airfoil performance determines the overall performance of a pump-jet propulsion system, and the airfoil profile directly affects the airfoil's hydrodynamic performance, a suitable airfoil parameterization method is needed to express the continuous and smooth airfoil geometry. This invention provides a fully parameterized pump-jet propulsion design method, specifically including the following steps:

[0032] S1: Select the stator airfoil, rotor airfoil, and duct airfoil of the pump-jet propulsion system as needed, and determine the following parameters:

[0033] Based on the camber and thickness distribution lines of the stator airfoil, rotor airfoil, and duct airfoil in different radial directions, the characteristic parameters of the airfoil profile are determined: chord, maximum camber, maximum thickness, leading edge radius, and trailing edge radius.

[0034] like Figure 1 As shown, parametric modeling enables flexible control of the airfoil shape, transforming the geometric information of the solid model into feature parameters. By defining feature parameters, the solid model can be accurately expressed, and by changing the feature parameters, the solid model can be altered.

[0035] like Figure 1As shown, the most forward point on the airfoil section is called the leading edge point, and the last point is called the trailing edge point. The distance between the leading edge point and the trailing edge point is the chord. The upper surface of the airfoil section has a faster flow rate (suction surface), and the lower surface has a slower flow rate (pressure surface). Taking the trailing edge tip as the center, a circle is drawn from the trailing edge to the leading edge direction, tangent to the pressure surface and suction surface. Connecting all the circle centers forms the camber distribution line of the airfoil section. The maximum value of the distance between the centerline and the inner chord is called the maximum camber. The maximum distance between the suction surface and the pressure surface is the maximum thickness. Different leading edge and trailing edge shapes will cause different changes in the performance of the airfoil section. In addition, the thickness of the trailing edge must meet the design requirements. Therefore, the leading edge radius and the trailing edge radius are set as characteristic parameters to control the shape of the leading edge and the trailing edge, which can make the change of the airfoil shape more flexible.

[0036] Rake, skew and pitch of the airfoil section of the rotor airfoil at different radial positions

[0037] Rotation angle of the stator;

[0038] Relative distance between the rotor and the stator;

[0039] S2: Using three-dimensional modeling software, establish airfoil section models of the stator airfoil, the rotor airfoil and the duct airfoil at different radial positions

[0040] According to the camber distribution line, the thickness distribution line and the characteristic parameters, the characteristic parameter description method is used to establish airfoil section models of the stator airfoil, the rotor airfoil and the duct airfoil at different radial positions;

[0041] S3: Using three-dimensional modeling software, establish a rotor model

[0042] According to the chord length, the maximum camber, the maximum thickness, the rake, the skew and the pitch of the airfoil section model of the rotor airfoil at different radial positions, obtain the original parameter curves of the rotor airfoil: the maximum chord length curve, the maximum thickness curve, the maximum camber curve, the pitch curve, the rake curve and the skew curve;

[0043] The chord length curve, the maximum thickness curve and the maximum camber curve can express the shape of the rotor airfoil. The rake curve, the skew curve and the pitch curve can express the distribution of the rotor airfoil in the circumferential, axial and radial airfoil sections.

[0044] According to the F-spline curve fitting principle, the original parameter curve of each rotor airfoil is fitted to obtain a corresponding rotor airfoil fitting parameter curve, and in the curve fitting process, the fitting point variance of the final rotor airfoil fitting parameter curve and the rotor airfoil original parameter curve is ensured to be minimum, and the rotor airfoil surface model is obtained through integration according to the rotor airfoil fitting parameter curve;

[0045] The present application uses fewer control variables to accurately fit the curve and the idea of minimum fitting point variance, greatly reducing the error between the fitting parameter curve and the original parameter curve; using F-Spline curve to express the characteristic parameters of propeller blade parameters can clearly express the distribution of propeller chord length, thickness, camber, pitch, skew, and pitch parameters, and generate a smooth distribution curve after changing the parameters, and the rotor airfoil surface model generated in this way can maintain good smoothness.

[0046] In the three-dimensional modeling software, the rotor airfoil surface model is connected with the hub model constructed by Boolean operation to form a closed rotor model.

[0047] S4: According to the characteristic parameters corresponding to the airfoil profile model of the stator airfoil and the duct airfoil at different radial positions, a stator model and a duct model are established by using three-dimensional modeling software, and the stator model, the duct model and the rotor model are connected to form a complete pump-jet propeller model according to the rotation angle of the stator determined in step S1 and the relative distance between the rotor and the stator. The stator blade mainly plays a flow regulating role in the pump-jet propeller, to a certain extent, reduces the energy loss of the fluid accelerated and rotated by the rotor, that is, absorbs part of the rotational kinetic energy of the fluid at the outlet of the rotor and converts it into pressure energy, to a certain extent, can generate thrust and reduce noise.

[0048] Further, the rotor model includes a plurality of rotor airfoil surface models, and the other rotor airfoil surface models are obtained by copying and rotating one rotor airfoil surface model in the three-dimensional modeling software.

[0049] Further, the three-dimensional modeling software used is CAESES.

[0050] Further, it further includes step S5: adjusting the characteristic parameters corresponding to the airfoil profile model of the stator airfoil and the duct airfoil at different radial positions, the chord length, the maximum camber, the maximum thickness, the leading edge radius, the trailing edge radius, the pitch, the skew and the pitch of the airfoil profile model of the rotor airfoil at different radial positions, and the rotation angle of the stator and the relative distance between the rotor and the stator to realize the parameterization control of the pump-jet propeller model in the three-dimensional modeling software; specifically, by changing each parameter, the shape of the airfoil can be changed, and then the parameterization control of the pump-jet propeller can be realized.

[0051] Further, the F-spline curve fitting specifically comprises the following steps:

[0052] S31: for a rotor airfoil original parameter curve, selecting a head point and a tail point as reference points of a fitting curve, the head point representing a starting point of a first F-spline curve, and the tail point representing a terminal point of a second F-spline curve;

[0053] S32: intercepting n fitting points from the rotor airfoil original parameter curve from the head point to the tail point to fit the rotor airfoil original parameter curve, for each point intercepted, the point can be used as a terminal point of the first F-spline curve and a starting point of the second F-spline curve, and two F-spline curves corresponding to each point are fitted as an intermediate fitting curve, and finally n intermediate fitting curves are obtained;

[0054] S33: calculating variances of n fitting points intercepted from each intermediate fitting curve and n fitting points intercepted from the rotor airfoil original parameter curve, and taking an intermediate fitting curve with the smallest variance as a final rotor airfoil fitting parameter curve, and the variance calculation formula is as shown in the following formula:

[0055] s 2 =[(x1-x) 2 +...(x n -x) 2 ] / n

[0056] Wherein, s 2 represents the variance, x1....x n represents a value of each fitting point, x represents an average value of x1....x n , and n represents a fitting point quantity.

[0057] Further, step S32 intercepts 50 fitting points from the rotor airfoil original parameter curve from the head point to the tail point for curve fitting.

[0058] The pump-jet propeller model obtained by using the full-parameter pump-jet propeller design method provided in the application can be used to change the three-dimensional model of the pump-jet propeller by changing parameters through three-dimensional modeling software when optimizing the performance of the pump-jet propeller, so as to study the relationship between the geometric characteristics and performance of the pump-jet propeller, for example, when optimizing the hydrodynamic performance of the pump-jet propeller, a sufficient sample space for optimization calculation can be established by using the method provided in the application.

[0059] The present application can realize flexible control of the pump-jet propeller conduit shape, the stator shape, the stator rotation angle, the relative distance between the stator and the rotor and the rotor shape, and the parameterized modeling of the pump-jet propeller can better establish the relationship between the geometric characteristics of the pump-jet propeller and the performance of the pump-jet propeller, the flexibility ensures the high efficiency of the performance prediction and optimization of the pump-jet propeller, and the performance optimization system of the pump-jet propeller is improved.

[0060] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A fully parametric pump-jet propulsor design method, characterized by, Specifically comprising the following steps: S1: Selecting the stator airfoil, rotor airfoil and duct airfoil of the pump-jet propeller according to needs, and determining the following parameters: According to the camber distribution line and thickness distribution line of the airfoil profile at different radial directions of the stator airfoil, rotor airfoil and duct airfoil, the characteristic parameters of the airfoil profile are determined, including chord length, maximum camber, maximum thickness, leading edge radius and trailing edge radius; The pitch, skew and twist corresponding to the airfoil profile at different radial directions of the rotor airfoil; The rotation angle of the stator; The relative distance between the rotor and the stator; S2: Using a three-dimensional modeling software to establish the airfoil profile model at different radial directions of the stator airfoil, rotor airfoil and duct airfoil According to the camber distribution line, thickness distribution line and characteristic parameters, the airfoil profile model at different radial directions of the stator airfoil, rotor airfoil and duct airfoil is respectively established by using the characteristic parameter description method; S3: Using a three-dimensional modeling software to establish the rotor model According to the chord length, maximum camber, maximum thickness, pitch, skew and twist corresponding to the airfoil profile model at different radial directions of the rotor airfoil, the original parameter curves of the rotor airfoil are obtained, including maximum chord length curve, maximum thickness curve, maximum camber curve, pitch curve, skew curve and twist curve; According to the F-spline curve fitting principle, the original parameter curves of the rotor airfoil are curve fitted to obtain the corresponding fitting parameter curves of the rotor airfoil, and in the curve fitting process, the point variance of the fitting parameter curves of the rotor airfoil and the original parameter curves of the rotor airfoil is ensured to be minimum, and the rotor airfoil surface model is obtained by integration according to the fitting parameter curves of the rotor airfoil; In the three-dimensional modeling software, the rotor airfoil surface model is connected with the hub model constructed by Boolean operation to form a closed rotor model; S4: According to the characteristic parameters corresponding to the airfoil profile model at different radial directions of the stator airfoil and duct airfoil, the stator model and duct model are established by using a three-dimensional modeling software, and the stator model, duct model and rotor model are connected to form a complete pump-jet propeller model according to the rotation angle of the stator and the relative distance between the rotor and the stator determined in step S1.

2. The full parametric pump-jet propulsor design method of claim 1, wherein, The rotor model includes a plurality of rotor airfoil surface models, and other rotor airfoil surface models are obtained by copying and rotating one rotor airfoil surface model in the three-dimensional modeling software.

3. The full parametric pumpjet propulsor design method of claim 1, wherein, The three-dimensional modeling software used is CAESES.

4. The full parametric pump-jet propulsor design method of claim 1, wherein, Further comprising step S5: adjusting the characteristic parameters corresponding to the airfoil profile model at different radial directions of the stator airfoil and duct airfoil, the chord length, maximum camber, maximum thickness, leading edge radius, trailing edge radius, pitch, skew and twist corresponding to the airfoil profile model at different radial directions of the rotor airfoil, and the rotation angle of the stator and the relative distance between the rotor and the stator in the three-dimensional modeling software to realize the parameterization control of the pump-jet propeller model.

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