A design method for double-channel volute

Abstract

The present invention discloses a design method for a double-channel volute. The present invention designs a double-channel asymmetric volute cross-sectional shape, which is based on a pear shape and has two halves, the upper and lower halves, and the area size can be changed without crossing; a parametric modeling method for a double-channel volute is provided, which divides a single-sided volute into a spiral section, a pre-swirl section, and an inlet section. The spiral section can calculate the large arc radius of the cross section of the volute at different azimuths according to the given volute inlet aerodynamic parameters and geometric parameters. The cross sections of the pre-swirl section and the inlet section extend from the maximum cross section of the spiral section and degenerate into a general shape. Only the cross sections at the two ends are controlled, and the middle is lofted and modeled; all cross-sectional profiles can be calculated using a spatial coordinate calculation formula to obtain spatial coordinate points; the inlet flow rates of the volutes on both sides are allocated according to the asymmetric factor, and other inlet parameters are the same, so that two asymmetric single-sided volutes can be designed, and then the bottom surfaces are combined to obtain a double-channel asymmetric volute. This method improves the design accuracy and efficiency of the double-channel volute.

Description

Technical Field

[0001] The invention relates to the technical field of exhaust gas guide component design of a multi-cylinder engine turbocharger, and more specifically, to a design method for a double-channel volute. Background Art

[0002] In a turbocharger, the main function of the turbine volute is to collect the exhaust gas discharged by the accelerated engine and make it impact the turbine at a certain angle. The volute is widely used in various automotive and ship turbochargers, and plays an irreplaceable role in the fields of national defense and civil industry. The volute is one of the core components of the turbocharger turbine. Its main function is to accelerate and guide the engine exhaust gas to meet the turbine's intake requirements and improve the turbine's working capacity.

[0003] At present, the design of turbine volute profile mainly includes the design of volute spiral section, volute pre-swirl section and volute inlet section. The most commonly used design method is to divide the volute cross section into two parts: trapezoidal and circular parts based on the law of conservation of momentum of gas flow in the volute, calculate the law of change of volute profile with azimuth angle, and then use CAD software to shape it. This method works better when facing relatively simple cross-sectional shapes, but it is difficult to deal with situations with more complex cross-sectional shapes. In addition, with the development of multi-cylinder engines, traditional single-channel volutes will have intake interference problems, which will lead to increased airflow chaos, increase airflow losses, and weaken the flow guidance and acceleration effect of the volute. Summary of the invention

[0004] The present invention aims at the technical defects existing in the prior art and provides a double-channel volute design method based on parametric modeling, which solves the intake interference problem to a certain extent and adapts to different intake conditions through asymmetric design.

[0005] The technical solution adopted to achieve the purpose of the present invention is:

[0006] A method for designing a double-channel volute, wherein the design of the spiral segment profile of the volute comprises the following steps:

[0007] (1) Calculate the minimum cross-sectional arc radius r1 and its azimuth angle θ0 of the volute based on the given volute design geometric parameters and aerodynamic parameters;

[0008] The calculation formula for the minimum cross-sectional arc radius r1 of the volute in step (1) is as follows:

[0009]

[0010] Where: C is 1 / 2 of the gap between the two channels, b r is the outlet width, γ is the channel structure angle, δ = γ / 2.

[0011] The calculation formula of the minimum cross-sectional azimuth angle θ0 in step (1) is the following equation group:

[0012]

[0013] Where: k is the integral constant coefficient, ρ is the gas density at the volute inlet, c u is the tangential component of the absolute velocity at the volute outlet, r0 is the volute outlet radius, is the velocity loss coefficient; s1 is the radial length of segment 1, b r is the volute outlet width, C is 1 / 2 of the gap between the two channels, bt is the confluence angle; s'2 is the radial length of the minimum cross-section line segment 3, its value is 0, γ is the channel structure angle, δ is 1 / 2 of γ; R'0 is the distance from the center of the minimum cross-section large arc to the center of the base circle, R h is the base circle radius, r1 is the radius of the minimum cross-section arc of the volute; G' θ1 is the mass flow rate through the small triangle of the confluence section; G' θ2 is the mass flow rate through the trapezoid, G' θ3 is the mass flow rate through the arc-edge trapezoid, G' θ4 is the mass flow rate through the semicircle, G T is the total flow through the volute. The geometric meaning of the relevant parameters is as follows Figure 1 shown.

[0014] (2) Let the volute cross-section azimuth angle θ∈[θ0,360 0 ]The radius of the arc of the volute section corresponding to is r1;

[0015] (3) The implicit format iterative calculation method is used to calculate the arc radius r3 of the volute section corresponding to the azimuth angle of the volute section is 0; the implicit format iterative calculation method is generally to let r3 increase from r1, and substitute r3 into the calculation equation group to calculate the phase angle θ ,when θ When it is less than 0, the iteration stops. θ Corresponding r That is r3, the calculation equations are as follows:

[0016]

[0017] Where: k is the integral constant coefficient, ρ is the gas density at the volute inlet, c 1u is the tangential component of the absolute velocity at the volute outlet, r0 is the volute outlet radius, is the velocity loss coefficient; s1 is the radial length of segment 1, b ris the outlet width of the volute, C is 1 / 2 of the gap between the two channels, bt is the confluence angle; s'2 is the radial length of the maximum cross-sectional line segment 3, γ is the channel structural angle, δ is 1 / 2 of γ; R'0 is the distance from the center of the large arc of the cross section to the center of the base circle, R h is the base circle radius; G” θ1 is the mass flow rate through the small triangle of the confluence section; G” θ2 is the mass flow rate through the trapezoid, G” θ3 is the mass flow rate through the arc-edge trapezoid, G” θ4 is the mass flow rate through the semicircle, G T is the total flow through the volute. The geometric meaning of the relevant parameters is as follows Figure 1 shown.

[0018] (4) Select the radius r from [r1, r3] and substitute it into the calculation equation group to obtain the corresponding azimuth angle θ. The calculation equation group is:

[0019]

[0020] Where: k is the integral constant coefficient, ρ is the gas density at the volute inlet, c 1u is the tangential component of the absolute velocity at the volute outlet, r0 is the volute outlet radius, is the velocity loss coefficient; s1 is the radial length of segment 1, b r is the outlet width of the volute, C is 1 / 2 of the gap between the two channels, bt is the confluence angle; s2 is the radial length of the maximum cross-sectional line segment 3, γ is the channel structural angle, δ is 1 / 2 of γ; R0 is the distance from the center of the large arc of the cross section to the center of the base circle, R h is the base circle radius; G θ1 G is the mass flow rate through the small triangle of the confluence section; θ2 is the mass flow rate through the trapezoid, G θ3 is the mass flow rate through the arc-edge trapezoid, G θ4 is the mass flow rate through the semicircle, G T is the total flow through the volute. The geometric meaning of the relevant parameters is as follows Figure 1 shown.

[0021] (5) The spatial coordinates (x, y, z) of the cross-section circle at any volute cross-section azimuth angle θ are calculated according to the spatial coordinate parameter equation of the cross-section circle at any volute cross-section azimuth angle θ; the spatial coordinate system is as follows: Figure 2 As shown, the coordinate parameter equation is:

[0022] Line segment 1:

[0023]

[0024] The position of line segment 1 in the cross section is as follows Figure 3As shown. In the formula, R h is the base circle radius, b r is the volute outlet width, γ is the channel structure angle, δ = γ / 2, C is 1 / 2 of the gap between the two channels, r is the radius of the large arc, θ is the volute section azimuth, and β is the line segment interpolation parameter, which ranges from [0,1].

[0025] Line segment 2:

[0026]

[0027] The position of line segment 2 in the cross section is as follows Figure 4 As shown. In the formula, R h is the base circle radius, b r is the volute outlet width, γ is the channel structure angle, δ = γ / 2, C is 1 / 2 of the gap between the two channels, r is the radius of the large arc, θ is the volute section azimuth, and β is the line segment interpolation parameter, which ranges from [0,1].

[0028] Great Circle:

[0029]

[0030] The position of the large arc in the cross section is as follows Figure 5 As shown. In the formula, R h is the base circle radius, b r is the volute outlet width, γ is the channel structure angle, δ = γ / 2, C is 1 / 2 of the gap between the two channels, r is the radius of the large arc, θ is the volute section azimuth, and α is the arc interpolation parameter, which has a range of

[0031] Line segment 3:

[0032]

[0033] The position of line segment 3 in the cross section is as follows Figure 6 As shown. In the formula, R h is the base circle radius, b r is the volute outlet width, γ is the channel structure angle, δ = γ / 2, C is 1 / 2 of the gap between the two channels, r is the radius of the large arc, θ is the volute section azimuth, and β is the line segment interpolation parameter, which ranges from [0,1].

[0034] (6) The spatial profile of the cross-section circle of the spiral section of the volute is obtained based on the spatial coordinates of the cross-section circle at different volute cross-section azimuths.

[0035] A method for designing a double-channel volute, wherein the design of a pre-swirl section profile of the volute comprises the following steps:

[0036] 1) Let the pre-spin angle be θ, that is, the pre-spin section azimuth angle be -θ, and the starting section of the pre-spin section be at θ = 0 0 Modification based on the cross section: First, the radial position increases by Δh, line segment 1 disappears, and the coordinate points of the remaining parts are relative to θ = 0 0 The coordinate point changes an azimuth angle, and a small arc segment is added. The starting section of the pre-rotation segment is as follows Figure 7 As shown. The calculation formula of Δh is:

[0037]

[0038] Where: C is 1 / 2 of the gap between the two channels, b r is the outlet width, and γ is the channel structure angle. The geometric relationship of Δh is as follows Figure 7 shown.

[0039] 2) According to the variable azimuth formula, the spatial coordinates of the starting section segment 2, the great circle arc, and the segment 3 are obtained The variable azimuth formula is:

[0040]

[0041] Where, X 00 The phase angle is 0 0 The x-coordinate of the cross section, Z 00 The phase angle is 0 0 The z-coordinate of the cross section.

[0042] 3) According to the small arc space coordinate parameter equation, the small arc space coordinate (X D ,Y D ,Z D ). The parametric equation is:

[0043]

[0044] Where: R h is the radius of the base circle, s1 is the radial length of segment 1 on the starting section of the spiral segment, Δh is the radial fixed increment of the starting section of the pre-spin segment, b r is the volute outlet width, C is 1 / 2 of the gap between the two channels, γ is the channel structure angle, and α is the arc interpolation parameter. Combine in order and (X D ,Y D ,Z D ) to obtain the complete pre-rotation section starting section coordinates (Xr, Yr, Zr)

[0045] 4) Take the starting section of the spiral section as the ending section of the pre-spin section. The profile line between the two surfaces does not need to be specifically designed. The result after surface lofting is suitable.

[0046] The design of the inlet section profile of the volute comprises the following steps:

[0047] ① Let the shape of the volute inlet be a capsule consisting of two line segments of length H and two semicircles of radius r3. Figure 8 As shown, the calculation formula of H is as follows:

[0048] H=s2cos 2 δ (12)

[0049] Where: s2 is the radial distance of line segment 3, and δ is 1 / 2 of the construction angle γ.

[0050] ② Let the inlet section be parallel to the starting section of the pre-swirl section, the distance between the two sections is L, and the centroids of the two sections have the same radial distance when L = 0. The spatial position of the section is as follows Figure 2 As shown. The calculation formula for the cross-sectional spacing L is:

[0051] L=1.5R h (13)

[0052] Where: R h is the base circle radius.

[0053] ③According to the spatial coordinate formula, the spatial coordinates of the inlet section are obtained, and then the inlet section profile is obtained. The spatial coordinate formula is as follows:

[0054] Side 1:

[0055]

[0056] The corresponding part of edge 1 in the cross section is as follows Figure 8 As shown. In the formula, R li is the distance from the centroid of the inlet section to the center of the base circle, H is the length of side 1 and side 2 of the inlet section, L is the distance from the inlet section to the starting section of the pre-rotation segment, and β is the interpolation parameter.

[0057] Semicircle 1:

[0058]

[0059] The corresponding part of semicircle 1 in the cross section is as follows Figure 8 As shown. In the formula, R li is the distance from the centroid of the inlet section to the center of the base circle, r3 is the radius of the large arc of the maximum section of the spiral segment, H is the length of sides 1 and 2 of the inlet section, L is the distance from the inlet section to the starting section of the pre-spin section, C is 1 / 2 of the gap between the two channels, and t and β are both interpolation parameters.

[0060] Side 2:

[0061]

[0062] The corresponding part of edge 2 in the cross section is as follows Figure 8 As shown. In the formula, R li is the distance from the centroid of the inlet section to the center of the base circle, r3 is the radius of the large arc of the maximum section of the spiral segment, H is the length of side 1 and side 2 of the inlet section, L is the distance from the inlet section to the starting section of the pre-spin section, C is 1 / 2 of the gap between the two channels, and t and β are both interpolation parameters.

[0063] Semicircle 2:

[0064]

[0065] Where: R li is the distance from the centroid of the inlet section to the center of the base circle, H is the length of the side 1 and side 2 of the inlet section, r3 is the radius of the large arc of the maximum section of the spiral segment, L is the distance from the inlet section to the starting section of the pre-spin section, and t and β are both interpolation parameters. Figure 8 As shown. li The calculation formula is:

[0066] R li =y o cosδ+(2+sinγ-cosδ)r1+R h (18)

[0067] In the formula, y o Indicates the position of the centroid of the starting cross section of the pre-rotation segment, such as Fig. 9 As shown, δ is 1 / 2 of the channel structure angle γ, r1 is the minimum cross-sectional arc radius, R h is the base circle radius. o The calculation formula is:

[0068]

[0069] Where y1 represents the center of the small arc; y2 represents the centroid of the trapezoid; y3 represents the centroid of the large arc; the centroid positions are as follows: Fig. 9 As shown, r3 is the maximum cross-sectional arc radius, δ is 1 / 2 of the channel structure angle γ, r1 is the minimum cross-sectional arc radius, and h is the height of the cross section in the direction of its own symmetry axis, as shown in Fig. 9 As shown, the calculation formula of h is as follows:

[0070] h=s2cosδ (20)

[0071] Where s2 is the radial distance of line segment 3, and δ is 1 / 2 of the construction angle γ.

[0072] The calculation formula of y1 is as follows:

[0073]

[0074] Where r1 is the minimum cross-sectional arc radius, γ is the channel structural angle, and δ is 1 / 2 of γ. The calculation formula of r1 is as follows:

[0075]

[0076] Where: C is 1 / 2 of the gap between the two channels, b r is the outlet width, γ is the channel structure angle, δ = γ / 2.

[0077] The calculation formula of y2 in formula (19) is:

[0078]

[0079] In the formula, r1 is the minimum cross-sectional arc radius, γ is the channel structural angle, δ is 1 / 2 of γ, and h is the height of the cross section in the direction of its own symmetry axis. The calculation formula of r1 is as follows:

[0080]

[0081] Where: C is 1 / 2 of the gap between the two channels, b r is the outlet width, γ is the channel structure angle, δ = γ / 2.

[0082] The calculation formula of h in formula (23) is as follows:

[0083] h=s2cosδ (25)

[0084] Where s2 is the radial distance of line segment 3, and δ is 1 / 2 of the construction angle γ.

[0085] In formula (19), the calculation formula of y3 is as follows:

[0086]

[0087] Where r3 is the maximum cross-sectional arc radius of the spiral segment, γ is the channel structural angle, and δ is 1 / 2 of γ.

[0088] ④ Take the starting section of the pre-swirl section as the ending section of the inlet section. The profile line between the two surfaces does not need to be designed specifically. The result after surface lofting is suitable.

[0089] Combining the inlet coordinates of the spiral section, pre-swirl section, and inlet section of the volute above can obtain the structure of a single-sided volute. To obtain a double-channel volute, the following steps are required:

[0090] ① Using the above volute modeling method, design another volute with different channel cross-section sizes according to the size of the asymmetric factor. The formula of the asymmetric factor is as follows:

[0091]

[0092] Where: G t1 is the inlet flow rate of volute 1, G t2 is the inlet flow rate of volute 2.

[0093] ② The bottom surfaces of the two volutes are joined together to obtain a double-channel volute.

[0094] Compared with the prior art, the present invention has the following beneficial effects:

[0095] 1. The design method of the volute profile of the present invention performs segmented processing on the volute cross section, broadens the design range of the parametric modeling method, and improves the design accuracy.

[0096] 2. The present invention adopts a pear shape as the passage cross section of the volute, which is beneficial to improving the aerodynamic performance of the equipment.

[0097] 3. The present invention designs a double-channel volute, which is beneficial to solving the problem of air intake interference, reducing aerodynamic losses, and expanding the application range of the turbocharger.

[0098] 4. The present invention provides a design method for the volute pre-swirl section and the inlet section, which provides a reference for engineering practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Figure 1 The figure shows the cross-sectional shape of the spiral section of the volute and the schematic diagram of the related parameters of the design method of the volute of the present invention;

[0100] Figure 2 Shown is a schematic diagram of the spatial position of the volute cross-section profile and the spatial coordinate system;

[0101] Figure 3 The figure shows a schematic diagram of a cross-sectional profile line segment 1 of a spiral segment of a volute;

[0102] Figure 4 The figure shows a schematic diagram of a cross-sectional profile line segment 2 of a spiral section of a volute;

[0103] Figure 5 The figure shows the large arc schematic diagram of the cross-section profile of the spiral section of the volute;

[0104] Figure 6 The figure shows a schematic diagram of a cross-sectional profile line segment 3 of the spiral segment of the volute;

[0105] Figure 7 Shown is a schematic diagram of the relative position of the starting section of the pre-rotation section and the small arc segment added;

[0106] Figure 8 The figure shows the cross-sectional shape of the inlet section and the schematic diagram of the sections;

[0107] Fig. 9The figure shows the centroid position and relative height of the starting cross section of the pre-rotation section;

[0108] Fig.10 The figure shows the volute section azimuth angle θ and the volute section arc radius r1 in θ∈[θ0,360 0 ] within the range of function relationship;

[0109] Fig.11 The figure shows the functional relationship between the arc radius r of the volute section and the azimuth angle θ of the volute section in the range of r∈[r1,r3];

[0110] Fig.12 The figure shows the volute section azimuth angle θ and the volute section large arc radius r. Functional relationship within the range;

[0111] Fig.13 The figure shows the cross-sectional spatial profile of the spiral section of the volute;

[0112] Fig.14 The complete spatial profile of the volute 1 is shown;

[0113] Fig.15 Shown is the spatial profile of the volute 2;

[0114] Fig.16 Shown is the overall profile of a double channel volute. DETAILED DESCRIPTION

[0115] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0116] The design method of the volute of the present invention includes the design of the volute spiral segment profile, the volute pre-swirl segment profile and the volute inlet segment profile. The schematic diagram of the cross section of the volute spiral segment is as shown in FIG. Figure 1 As shown, the space view of the spiral section, pre-swirl section and inlet section of the volute is as follows Figure 2 The spiral segment profile design of the volute includes the following steps:

[0117] (1) Compared with the prior art, the present invention first calculates the minimum cross-sectional arc radius r1 and the minimum cross-sectional azimuth θ0 of the volute according to the given flow parameters of the volute inlet cross section and the volute design geometric parameters. The aerodynamic parameters of the volute inlet cross section include the asymmetry factor D, the volute inlet mass flow rate G t1 , the tangential component of the absolute velocity at the volute inlet c 1u , gas density ρ in the volute passage, velocity loss coefficient The volute design geometric parameters include: volute outlet radius r0, volute inlet width b r , base circle radius R h , channel structure angle γ, confluence angle bt. The calculation formula for the minimum cross-sectional arc radius r1 of the volute is:

[0118]

[0119] The calculation formula of the minimum cross-sectional azimuth angle θ0 is as follows:

[0120]

[0121] Where: k is the integral constant coefficient, ρ is the gas density at the volute inlet, c 1u is the tangential component of the absolute velocity at the volute outlet, r0 is the volute outlet radius, is the velocity loss coefficient; s1 is the radial length of segment 1, b r is the volute outlet width, C is 1 / 2 of the gap between the two channels, bt is the confluence angle; s'2 is the radial length of the minimum cross-section line segment 3, its value is 0, γ is the channel structure angle, δ is 1 / 2 of γ; R'0 is the distance from the center of the minimum cross-section large arc to the center of the base circle, R h is the base circle radius, r1 is the radius of the minimum cross-section arc of the volute; G' θ1 is the mass flow rate through the small triangle of the confluence section; G' θ2 is the mass flow rate through the trapezoid, G' θ3 is the mass flow rate through the arc-edge trapezoid, G' θ4 is the mass flow rate through the semicircle, G T is the total flow through the volute. The geometric meaning of the relevant parameters is as follows Figure 1 shown.

[0122] (2) Let the range of the angular range of the volute section be [θ0,360 0 ]The corresponding volute cross-section circle radius is r1.

[0123] (3) The implicit format iterative calculation method is used to calculate the radius r3 of the large arc of the volute section corresponding to the azimuth angle of 0. The calculation formula of the radius r3 of the volute section circle corresponding to the azimuth angle of 0 is:

[0124]

[0125] Where: k is the integral constant coefficient, ρ is the gas density at the volute inlet, c 1u is the tangential component of the absolute velocity at the volute outlet, r0 is the volute outlet radius, is the velocity loss coefficient; s1 is the radial length of segment 1, b r is the outlet width of the volute, C is 1 / 2 of the gap between the two channels, bt is the confluence angle; s'2 is the radial length of the maximum cross-sectional line segment 3, γ is the channel structural angle, δ is 1 / 2 of γ; R'0 is the distance from the center of the large arc of the cross section to the center of the base circle, R h is the base circle radius; G” θ1is the mass flow rate through the small triangle of the confluence section; G” θ2 is the mass flow rate through the trapezoid, G” θ3 is the mass flow rate through the arc-edge trapezoid, G” θ4 is the mass flow rate through the semicircle, G T is the total flow through the volute. The geometric meaning of the relevant parameters is as follows Figure 1 shown.

[0126] (4) Select any radius r in [r1, r3] and substitute it into the calculation formula to obtain the corresponding azimuth angle θ, then θ∈[0, θ0]; the calculation formula for the volute section phase angle θ corresponding to the volute section large arc radius range [r1, r3] is as follows:

[0127]

[0128] Where: k is the integral constant coefficient, ρ is the gas density at the volute inlet, c 1u is the tangential component of the absolute velocity at the volute outlet, r0 is the volute outlet radius, is the velocity loss coefficient; s1 is the radial length of segment 1, b r is the outlet width of the volute, C is 1 / 2 of the gap between the two channels, bt is the confluence angle; s2 is the radial length of segment 3, γ is the channel structure angle, δ is 1 / 2 of γ; R0 is the distance from the center of the large arc of the cross section to the center of the base circle, R h is the base circle radius; G θ1 is the mass flow rate through the small triangle of the confluence section; G θ2 is the mass flow rate through the trapezoid, G θ3 is the mass flow rate through the arc-edge trapezoid, G θ4 is the mass flow rate through the semicircle, G T is the total flow through the volute.

[0129] (5) Take the union of the volute sections corresponding to step (3) and step (4) to obtain the volute section azimuth θ∈[0,360 0 ] is the set of large arc radii of the volute cross section corresponding to the range.

[0130] (6) The spatial coordinates (X, Y, Z) of the cross-section circle at any volute cross-section azimuth angle θ are calculated based on the spatial coordinate parameter equation of the cross-section at any volute cross-section azimuth angle. The spatial coordinates here are the Cartesian coordinate system of space. The spatial coordinate parameter equation of the cross-section at any volute cross-section azimuth angle is:

[0131] Line segment 1:

[0132]

[0133] Line segment 2:

[0134]

[0135] Great Circle:

[0136]

[0137] Line segment 3:

[0138]

[0139] Where: R h is the base circle radius, b r is the volute outlet width, γ is the channel structure angle, δ = γ / 2, C is 1 / 2 of the gap between the two channels, r is the radius of the large arc, θ is the volute section azimuth, β is the line segment interpolation parameter, β∈[0,1]; α is the arc interpolation parameter, The positions of the segments in the cross section are as follows: Figures 3 to 6 As shown, after taking the union of the coordinates of each segment in order, the cross-sectional space coordinates (X, Y, Z) can be obtained.

[0140] (7) The spatial profile of the spiral section circle of the volute is obtained based on the spatial coordinates of the cross-sectional circles of different spiral sections.

[0141] After obtaining the spatial coordinates of the cross-sectional circle at any azimuth angle of the volute helical section, the spatial three-dimensional coordinates of the pre-swirl section and the inlet section are calculated. The complete single-sided volute structure can be obtained by combining the three.

[0142] The design method of the pre-swirl section of the volute of the present invention is:

[0143] 1) Let the pre-rotation angle be That is, the azimuth angle of the starting section of the pre-rotation section is

[0144] 2) At θ = 0 0 Modify the starting section of the pre-spin segment based on the section: first, the radial position increases by Δh, line segment 1 disappears, and the coordinate points of the remaining part are relative to θ = 0 0 The cross-sectional coordinate point changes an azimuth angle, and a small arc segment is added. The starting cross-sectional area of ​​the pre-rotation segment is as follows: Figure 7 As shown. The calculation formula of Δh is:

[0145]

[0146] Where: C is 1 / 2 of the gap between the two channels, b r is the outlet width, and γ is the channel structure angle. The geometric relationship of Δh is as follows Figure 7 shown.

[0147] 3) According to the variable azimuth formula, the spatial coordinates of the starting section segment 2, the large arc, and the segment 3 are obtained The variable azimuth formula is:

[0148]

[0149] In the formula, X 00 The phase angle is 0 0 The x-coordinate of the cross section, Z 00 The phase angle is 0 0 The z coordinate of the cross section, where the spatial coordinate is the Cartesian coordinate system of space.

[0150] 4) According to the small arc space coordinate parameter equation, the small arc space coordinate (X D ,Y D ,Z D ). The parametric equation is:

[0151]

[0152] Where: R h is the radius of the base circle, s1 is the radial length of segment 1 on the starting section of the spiral segment, Δh is the radial fixed increment of the starting section of the pre-spin segment, b r is the volute outlet width, C is 1 / 2 of the gap between the two channels, γ is the channel structure angle, α is the arc interpolation parameter, and the value range of α is

[0153] (X -θ ,Y -θ ,Z -θ ) and (X D ,Y D ,Z D ) are combined in sequence to obtain the spatial coordinates (Xr, Yr, Zr) of the starting section of the complete volute pre-swirl section, and then the spatial profile of the section is obtained.

[0154] 5) Take the starting section of the spiral section as the ending section of the pre-spin section. The profile line between the two surfaces does not need to be specifically designed. The result after surface lofting is suitable.

[0155] The design method of the inlet section profile of the volute of the present invention is as follows:

[0156] ① Let the shape of the volute inlet be a capsule consisting of two line segments of length H and two semicircles of radius r3. Figure 8 As shown, the calculation formula of H is as follows:

[0157] H=s2cos 2 δ (12)

[0158] Where: s2 is the radial distance of line segment 3, and δ is 1 / 2 of the construction angle γ.

[0159] ② Let the inlet starting section be parallel to the pre-swirl starting section, the distance between the two sections is L, and the centroids of the two sections have the same radial distance when L = 0. The spatial position of the section is as follows Figure 2 As shown. The calculation formula for the cross-sectional spacing L is:

[0160] L=1.5R h (13)

[0161] Where: R h is the base circle radius.

[0162] ③According to the spatial coordinate parameter equation, the spatial coordinate of the inlet starting section is obtained, and then the inlet starting section profile is obtained. The spatial coordinate here is the Cartesian coordinate system of space. The spatial coordinate parameter equation is as follows:

[0163] Side 1:

[0164]

[0165] Semicircle 1:

[0166]

[0167] Side 2:

[0168]

[0169] Semicircle 2:

[0170]

[0171] Where: R li is the distance from the centroid of the inlet section to the center of the base circle, H is the length of the sides 1 and 2 of the inlet section, r3 is the radius of the largest arc of the helical section, θ is the phase angle of the pre-rotation section, L is the distance from the inlet section to the starting section of the pre-rotation section, and t and β are both interpolation parameters. li The calculation formula is:

[0172] R li =y o cosδ+(2+sinγ-cosδ)r1+R h (18)

[0173] In the formula, y o represents the position of the centroid of the starting section of the pre-spin section, δ is 1 / 2 of the channel structure angle γ, r1 is the radius of the minimum cross-sectional arc, R h is the base circle radius. The centroid position is as follows Fig. 9 As shown, y o The calculation formula is:

[0174] (19)

[0176] Where y1 represents the center of the small arc; y2 represents the centroid of the trapezoid; y3 represents the centroid of the large arc; the centroid positions are as follows: Fig. 9 As shown, r3 is the maximum cross-sectional arc radius, δ is 1 / 2 of the channel structure angle γ, r1 is the minimum cross-sectional arc radius, and h is the height of the cross section in the direction of its own symmetry axis, as shown in Fig. 9 As shown, the calculation formula of h is as follows:

[0177] h=s2cosδ (20)

[0178] Where s2 is the radial distance of line segment 3, and δ is 1 / 2 of the construction angle γ.

[0179] The calculation formula of y1 in formula (19) is as follows:

[0180]

[0181] Where r1 is the minimum cross-sectional arc radius, γ is the channel structural angle, and δ is 1 / 2 of γ. The calculation formula of r1 is as follows:

[0182]

[0183] Where: C is 1 / 2 of the gap between the two channels, b r is the outlet width, γ is the channel structure angle, δ = γ / 2.

[0184] The calculation formula of y2 in formula (19) is:

[0185]

[0186] Where: r1 is the minimum cross-sectional arc radius, γ is the channel structural angle, δ is 1 / 2 of γ, and h is the height of the cross section in the direction of its own symmetry axis. The calculation formula of r1 is as follows:

[0187]

[0188] Where: C is 1 / 2 of the gap between the two channels, b r is the outlet width, γ is the channel structure angle, δ = γ / 2.

[0189] In formula (23), the calculation formula of h is as follows:

[0190] h=s2cosδ (25)

[0191] Where s2 is the radial distance of line segment 3, and δ is 1 / 2 of the construction angle γ.

[0192] In formula (19), the calculation formula of y3 is as follows:

[0193]

[0194] Where r3 is the maximum cross-sectional arc radius of the spiral segment, γ is the channel structural angle, and δ is 1 / 2 of γ.

[0195] Combining the spatial coordinates of the above four segments in sequence can obtain the coordinates of the starting section of the complete volute inlet section, and then the cross-sectional profile can be obtained.

[0196] ④ Take the starting section of the pre-swirl section as the ending section of the inlet section. The profile line between the two surfaces does not need to be designed specifically. The result after surface lofting is suitable.

[0197] The spatial coordinates of the spiral section, pre-swirl section and inlet section of the volute are combined to obtain a complete single-sided volute structure. To obtain a double-channel volute, the following steps are required:

[0198] ① Using the above volute modeling method, design another volute with a different channel cross-section size according to the size of the asymmetric factor. The formula of the asymmetric factor is as follows:

[0199]

[0200] Where: G t1 is the known inlet flow rate of volute 1, G t2 is the unknown inlet flow rate of volute 2.

[0201] ② Mirror one of the volutes along the bottom surface and combine it with the bottom surface of the other volute to obtain a double-channel volute.

[0202] Example: The design process of a turbocharger volute is as follows:

[0203] 1) Given the inlet aerodynamic parameters of the volute, including: asymmetry factor D = 0.4481, volute inlet mass flow rate G t1 =1.10835kg / s, tangential component of absolute velocity of gas at volute outlet c 1u =336m / s, gas density in the volute passage ρ = 0.588141kg / m 3 , speed loss coefficient Given the volute design geometric parameters, including: volute outlet radius, r0 = 0.0785m, volute inlet width b r =0.0141m, base circle radius R h =0.0845m, pre-spin angle Confluence angle bt = 45 0 , channel structure angle γ = 45 0 Next, we will calculate the parameters and coordinates of the volute 1.

[0204] 2) Use formula (1) to calculate the minimum cross-sectional arc radius of the volute, r1 = 0.00292 m.

[0205] 3) Using formula (2), calculate the minimum cross-sectional arc radius of the volute corresponding to θ0 = 357 0

[0206] 4) Set the range of the volute section azimuth angle θ to θ∈[θ0,360 0 ] The corresponding volute section arc radius is positioned at r1, and the volute section azimuth angle θ and the volute section arc radius r1 are in θ∈[θ0,360 0 ]The functional relationship within the range is as follows Fig.10 shown.

[0207] 5) Use the implicit iterative calculation method to calculate the arc radius r3 of the volute section corresponding to the volute section azimuth angle of 0, r3 = 0.0324m.

[0208] 6) Let the range of the arc radius r of the spiral section of the volute be r∈[r1,r3]. For any given arc radius r of the volute section within this range, the corresponding volute section azimuth θ is calculated using formula (4). The functional relationship between the arc radius r of the volute section and the azimuth θ of the volute section within the range of r∈[r1,r3] is as follows: Fig.11 shown.

[0209] 7) Through steps 4), 5) and 6), θ∈[0 0 ,θ0] and θ∈[θ0,360 0 ] The radius of the large arc of the volute section corresponding to the volute section is obtained by taking the union of θ∈[0 0 ,360 0 The set of the volute section large arc radius r corresponding to the range of ], the volute section azimuth angle θ and the volute section large arc radius r are in The functional relationship within the range is as follows Fig.12 As shown; Fig.12 The specific data results are shown in Table 1 below.

[0210] Table 1: Volute section azimuth angle θ and the corresponding volute section large arc radius r

[0211] θ r(m) θ r(m) θ r(m) 360 0.00292 275.7747 0.01312 134.7695 0.02392 356.85 0.00292 269.1566 0.01372 125.779 0.02452 355.97 0.00352 262.3731 0.01432 116.6862 0.02512 355.05 0.00412 255.4291 0.01492 107.4936 0.02572 354.09 0.00472 248.3293 0.01552 98.2034 0.02632 353.10 0.00532 241.0781 0.01612 88.8178 0.02692 352.08 0.00592 233.6799 0.01672 79.3391 0.02752 351.03 0.00652 226.1387 0.01732 69.7692 0.02812 349.94 0.00712 218.4584 0.01792 60.1102 0.02872 348.82 0.00772 210.6429 0.01852 50.364 0.02932 347.67 0.00832 202.6957 0.01912 40.5325 0.02992 346.50 0.00892 194.6204 0.01972 30.6175 0.03052 345.29 0.00952 186.4203 0.02032 20.6208 0.03112 344.05 0.01012 178.0985 0.02092 10.544 0.03172 342.78 0.01072 169.6582 0.02152 0.3889 0.03232 341.48 0.01132 161.1023 0.02212 -1.3111 0.03242 340.15 0.01192 152.4338 0.02272 338.79 0.01252 143.6553 0.02332

[0212] 8) The spatial coordinates (X, Y, Z) of the cross-section circle at any azimuth angle θ are calculated using formulas (5) to (8). Some data results are shown in Table 2. The spatial profile of the cross-section of the spiral section of the volute is obtained based on the calculated spatial coordinates. The spatial profile of the cross-section of the spiral section of the volute is as follows: Fig.13 shown.

[0213] Table 2: Volute section azimuth Space coordinates of the circular line of the cross section

[0214]

[0215]

[0216] 9) Calculate the pre-swirl profile of the volute, given that the pre-swirl angle is 20 0 , that is, the phase angle of the starting section of the pre-swirl section is θ = -20 degrees. According to formula (9), the radial increase distance of the volute pre-swirl section is Δh = 0.0058 m. The small arc section and radial position of the pre-swirl section are as follows: Figure 7 shown.

[0217] 10) According to formula (10), calculate the spatial coordinates of the non-small arc section of the starting section of the volute pre-swirl section According to formula (11), the spatial coordinates (X D ,Y D ,Z D ), the results of some of the data after the collection are shown in Table 3 below. According to the calculated spatial coordinates, the spatial profile of the starting section of the volute pre-swirl section is obtained as follows Figure 2 .

[0218] Table 3: Space coordinates of the cross-section profile of the volute pre-swirl section

[0219]

[0220]

[0221] 11) Calculate the profile of the volute inlet section. From the geometric relationship, it is known that the radius of the semicircle 1 and semicircle 2 of the volute inlet section is r3 = 0.03242m. According to formula (12), the length of the side 1 and the side 2 is H = 0.059m. According to formula (13), the distance between the inlet section and the pre-swirl section is L = 0.1268m.

[0222] 12) According to formulas (14), (15), (16) and (17), the spatial coordinates Xr2, Yr2 and Zr2 of the volute inlet section can be calculated. Some data results are shown in Table 4. According to the calculated spatial coordinates, the spatial profile of the starting section of the volute inlet section is obtained as follows: Figure 2 .

[0223] Table 4: Space coordinates of the cross-section profile of the volute inlet section

[0224]

[0225]

[0226] 13) Steps 6) and 8) respectively obtain the spatial three-dimensional coordinates of the spiral section, pre-swirl section and inlet section of the volute, and combine the three to obtain the volute structure of one channel in the double-channel volute, which is volute 1. The spatial profile of the channel is as follows: Fig.14 shown.

[0227] 14) In order to obtain a double-channel volute, it is also necessary to obtain the volute structure of another channel, which is volute 2. The asymmetry factor is known to be D = 0.4481, and according to formula (27), G can be calculated t2 = 0.9 kg / s, other inlet conditions are the same as those of volute 1, and the spatial profile of volute 2 can be obtained by going through steps 2) to 14) again. Fig.15 shown.

[0228] 15) After mirroring the volute 2 relative to the bottom surface and combining it with the volute 1, the overall profile of the double-channel volute can be obtained as follows: Fig.16 shown.

Claims

1. A design method for a double-channel volute, characterized in that: The design of the spiral segment profile of the volute comprises the following steps: (1) Calculate the minimum cross-sectional arc radius r1 and its azimuth angle θ0 of the volute based on the given volute design aerodynamic parameters and geometric parameters; (2) Let the arc radius of the volute cross section corresponding to the volute cross section azimuth angle θ∈[θ0,360°] be r1; (3) The implicit iterative calculation method is used to calculate the arc radius r3 of the volute section corresponding to the volute section azimuth angle of 0; (4) Select the radius r from [r1, r3] and substitute it into the equations to obtain the corresponding azimuth angle θ; (5) Calculate the spatial coordinates (X, Y, Z) of the cross-sectional circle at any volute cross-sectional azimuth angle θ according to the spatial coordinate parameter equation of the cross-sectional circle at any volute cross-sectional azimuth angle θ; (6) obtaining the spatial profile of the cross-section circle of the spiral section of the volute according to the spatial coordinates of the cross-section circle at different volute cross-section azimuths; The aerodynamic and geometric parameters of the volute design given in step (1) include the volute inlet mass flow rate G t1 , the tangential component of the absolute velocity at the volute outlet c 1u , gas density ρ in the volute passage, velocity loss coefficient Asymmetry factor D, volute outlet radius r0, volute outlet width b r , base circle radius R h , channel structure angle γ, confluence angle bt; The calculation formula of the minimum cross-sectional arc radius r1 of the volute in step (1) is: Where: C is 1 / 2 of the gap between the two channels, δ = γ / 2; The calculation formula for the azimuth angle θ0 corresponding to r1 is: Where: k is the integral constant coefficient; s1 is the radial length of segment 1; s'2 is the radial length of segment 3 with the smallest cross section, and its value is 0; R'0 is the distance from the center of the arc with the smallest cross section to the center of the base circle; G' θ1 is the mass flow rate through the small triangle of the confluence section; G' θ2 is the mass flow rate through the trapezoid, G' θ3 is the mass flow rate through the arc-edge trapezoid, G' θ4 is the mass flow rate through the semicircle, G T is the total flow through the volute. The basic shape of the volute cross section is pear-shaped, while the minimum cross section degenerates into an arc, and the overall size is equivalent to the small triangle of the confluence section; The system of equations in step (4) is: Where: s2 is the radial length of line segment 3; R0 is the distance from the center of the large arc of the cross section to the center of the base circle; G θ1 is the mass flow rate through the small triangle of the confluence section; G θ2 is the mass flow rate through the trapezoid, G θ3 is the mass flow rate through the arc-edge trapezoid, G θ4 It is the mass flow through the semicircle. The shape of the volute cross section is based on the pear shape and is compounded with the small triangle of the confluence section. The size of the small triangle remains unchanged, and the pear shape will increase as the azimuth angle decreases. Its size can be determined by the radius r of the large arc. The spatial coordinate parameter equation of the cross-section circle at any volute cross-section azimuth angle θ in step (5) is: Line segment 1: Line segment 2: Great Circle: Line segment 3: Where: β is the line segment interpolation parameter, β∈[0,1]; α is the arc interpolation parameter, The segmentation of the cross-section line is obtained by dividing the cross-section hub counterclockwise from the hypotenuse of the small triangle of the confluence section, and according to the actual situation of the volute cross section, it is not closed at the volute outlet; The design method of the pre-swirl section profile of the volute is as follows: ①Let the pre-rotation angle be That is, the starting section azimuth is The cross section is modified on the basis of the cross section at θ = 0°: first, Δh is added to the radial position, line segment 1 disappears, the coordinate points of the remaining part change an azimuth relative to the coordinate points at θ = 0°, and a small arc segment is added at the same time. The starting cross section structure actually changes from the original composite shape to a complete pear shape, and a certain distance is added in the radial position; ②According to the variable azimuth formula, the spatial coordinates of the starting section segment 2, the great circle arc, and the segment 3 are obtained. ③According to the small arc space coordinate parameter equation, the space coordinate of the small arc (X D ,Y D ,Z D ); ④ The end section of the pre-spin section is the starting section of the spiral section. The profile line between the two surfaces does not need to be specifically designed. The result after the surface lofting is appropriate. The design method of the inlet section profile of the volute is: ① Let the shape of the volute inlet be a capsule consisting of two line segments of length H and two semicircles of radius r3, or a pear shape with the same size at both ends; ② Let the inlet section be parallel to the starting section of the pre-swirl section, the distance between the two sections is L, and the centroids of the two sections have the same radial distance when L=0; ③According to the spatial coordinate formula, the spatial coordinates of the inlet section are obtained, and then the inlet section profile is obtained; The inlet coordinates of the spiral section, pre-swirl section and inlet section of the volute can be combined to obtain a single-sided volute structure. If a double-channel volute is obtained, the following steps are required: ① Using the above volute modeling method, another volute with different channel cross-section sizes is designed according to the size of the asymmetric factor. The formula of the asymmetric factor is as follows: Where: G t1 is the inlet flow rate of volute 1, G t2 is the inlet flow rate of volute 2; ② The bottom surfaces of the two volutes are joined together to obtain a double-channel volute.

2. The method for designing a volute according to claim 1, characterized in that: The iterative formula for the arc radius r3 of the volute section with an azimuth angle of 0 in step (3) is as follows: Where: s″2 is the radial length of the maximum cross-sectional line segment 3; R″0 is the distance from the center of the cross-sectional large arc to the center of the base circle; G″ θ1 is the mass flow rate through the small triangle of the confluence section; G″ θ2 is the mass flow rate through the trapezoid, G″ θ3 is the mass flow rate through the arc-edge trapezoid, G″ θ4 It is the mass flow rate through the semicircle. The section with an azimuth angle of 0 in the volute section is the largest section in the spiral segment, and its large arc radius r3 is also the largest. Overall, its radial and axial dimensions are the largest.

3. The method for designing a volute according to claim 1, characterized in that: The calculation formula of Δh in step ① of the design method of the pre-swirl section profile of the volute is:

4. The method for designing a volute according to claim 1, characterized in that: The variable azimuth angle formula in step ② of the design method of the pre-swirl section profile of the volute is: Where: is the coordinate value of the point on the starting section of the spiral segment, and Δh is the radial fixed increment of the starting section of the pre-swirl segment.

5. The method for designing a volute according to claim 1, characterized in that: The spatial coordinate calculation formula of the small arc segment in step ③ of the design method of the pre-swirl segment profile of the volute is:

6. The method for designing a volute according to claim 1, characterized in that: The calculation formula of H in step ① of the design method of the inlet section profile of the volute is: H=s2cos 2 d (10) In step ① of the method for designing the inlet section profile of the volute, r3 is the arc radius of the volute cross section when the azimuth angle of the volute cross section is 0.

7. The method for designing a volute according to claim 1, characterized in that: The calculation formula of L in step ② of the design method of the inlet section profile of the volute is L=1.5R h (11).

8. The method for designing a volute according to claim 1, characterized in that: The calculation formula of the spatial coordinates in step ③ of the design method of the inlet section profile of the volute is: Side 1: Semicircle 1: Side 2: Semicircle 2: Where: R li is the distance between the centroid of the inlet section and the center of the base circle, H is the length of the inlet section side 1 and the inlet section side 2, r3 is the radius of the large arc of the maximum section of the spiral segment, L is the distance between the inlet section and the starting section of the pre-spin section, and t is the interpolation parameter; the R li The calculation formula is: R li =y o cosδ+(2+sinγ-cosδ)r1+R h (16) In the formula, y o represents the position of the centroid of the starting cross section of the pre-rotation segment; the y o The calculation formula is: In the formula, y1 represents the center position of the small arc; y2 represents the centroid position of the trapezoid; y3 represents the centroid position of the large arc; h is the height of the cross section in the direction of its own symmetry axis, and the calculation formula of h is as follows: h=s2 cosδ (18) The calculation formula of y1 is as follows: The calculation formula of y2 in formula (17) is: In formula (17), the calculation formula of y3 is as follows:

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