A biomimetic nautilus shell for a hydraulic retarder

Abstract

This invention discloses a biomimetic nautilus volute for a hydraulic retarder, belonging to the field of vehicle hydraulic auxiliary braking technology. The inner profile of the biomimetic nautilus volute is a closed circular curve. The outer profile of the biomimetic nautilus volute is located outside the inner profile and is a closed curve composed of an inlet section, a first vertical inlet section, a straight section, a guide section, a return section, an inlet arc section, and a second vertical inlet section connected sequentially. Both the guide section and the return section are arc-shaped. The centers of the guide section and the return section do not coincide and are both located within the envelope of the inner profile, but do not coincide with the center of the inner profile. The concave surface of the arc of the inlet arc section faces the straight section. The angle formed by the inlet arc section and the return section does not abut against the inner profile. This invention, through the biomimetic structure of a nautilus, improves the distribution of streamlines inside the volute based on existing volutes, thereby optimizing the volute performance, suppressing the generation of vortex regions, and improving the braking response characteristics of the hydraulic retarder.

Description

Technical Field

[0001] This invention belongs to the field of vehicle hydraulic auxiliary braking technology, specifically relating to a biomimetic nautilus volute for a hydraulic retarder. Background Technology

[0002] As an auxiliary braking device for vehicles, a hydraulic retarder converts the input kinetic energy into internal fluid energy through the interaction between the blades and the hydraulic transmission fluid, and dissipates the generated internal fluid energy to achieve the effect of slowing down and braking.

[0003] Traditional research on volute design has largely focused on centrifugal compressors. However, the flow direction of the working medium inside the volute of a hydraulic retarder is completely opposite to that of the working medium inside the volute of a centrifugal compressor. Therefore, existing hydraulic retarder volute designs lack systematic theories and methods. Figure 1 As shown, the hydraulic retarder includes a housing, a moving impeller, and a fixed impeller, wherein the volute is a flow channel machined into the housing (made of...). Figure 1 The dotted arrow on the right side of the housing indicates that it is part of the housing. In a hydraulic retarder, the flow of oil inside the volute is highly complex. When the oil flows along the volute profile (…),… Figure 2 During operation (as shown by the dashed line), not all oil flows smoothly into the hydraulic retarder's working chamber; some oil will flow back and merge with the inflow oil at the inlet. Existing volute profiles exhibit a clearly symmetrical structure, such as... Figure 3 As shown, Figure 3 From a visual perspective, the rotating impeller of the hydraulic retarder rotates clockwise. Under the influence of this rotation, most of the incoming oil flows into the volute from the right side and moves clockwise. However, a portion of the incoming oil flows into the volute from the left side. When the oil enters the volute and moves clockwise along its profile, as... Figure 4 As shown, a portion of the returning oil impacts the incoming oil from the left, forming a large vortex region in the upper left corner of the volute. This vortex region causes significant energy loss, occupies the flow area inside the volute, and leads to oil accumulation, hindering the rapid flow of oil into the hydraulic retarder wheel cavity. Therefore, it is necessary to optimize the volute structure.

[0004] Bionic technology, as an increasingly mature approach, has been widely applied in hydraulic machinery design by simulating biological structures and evolutionary processes. Therefore, designing the volute of a hydraulic retarder using bionic methods and optimizing its performance can improve the braking response characteristics of the hydraulic retarder. Summary of the Invention

[0005] In view of this, the present invention provides a biomimetic nautilus volute for a hydraulic retarder. By incorporating the structure of a nautilus, the distribution of streamlines inside the volute is improved based on the existing volute, thereby optimizing the volute performance, suppressing the generation of vortex regions, and improving the braking response characteristics of the hydraulic retarder.

[0006] This invention is achieved through the following technical solution:

[0007] A biomimetic nautilus shell for a hydraulic retarder includes: an inner profile surface and an outer profile surface;

[0008] Let the profile lines of the inner profile surface be called inner profile lines, and the profile lines of the outer profile surface be called outer profile lines; the inner profile line is a closed circular curve with a radius of r0;

[0009] The outer profile is located outside the inner profile and is a closed curve composed of the inlet section, the first inlet vertical section, the straight section, the guide section, the return section, the inlet arc section, and the second inlet vertical section connected in sequence; the length of the first inlet vertical section and the second inlet vertical section is L2;

[0010] Let the direction of the entrance segment be horizontal, and the direction perpendicular to the entrance segment be vertical; let the length of the entrance segment be L1, and the vertical distance between the entrance segment and the center of the inner profile be L3;

[0011] Both the guide section and the return section are arc-shaped; the centers of the guide section and the return section do not coincide, and both are located within the envelope of the inner profile line but do not coincide with the center of the inner profile line; the radius of the guide section is r2, the horizontal distance between the center of the guide section and the inner profile line is e1, and the vertical distance is e2; the horizontal distance between the center of the return section and the guide section is a1, and the vertical distance is a2.

[0012] The radius of the inlet arc segment is r1, and the concave surface of the arc faces the straight line segment; the angle formed by the inlet arc segment and the return segment does not collide with the inner profile line;

[0013] L1, L2, L3, r0, r1, r2, a1, a2, e1, and e2 determine the outer contour lines of the biomimetic nautilus shell.

[0014] Furthermore, the incoming oil flows into the biomimetic nautilus volute in the sequence of the first inlet vertical section, the second inlet vertical section, the inlet arc section, the guide section, and the return section;

[0015] The guide section is located on the side near the inlet of the oil, and the return section is located on the opposite side near the inlet of the oil.

[0016] Furthermore, the inlet arc segment is tangent to the second inlet vertical segment.

[0017] Furthermore, the guide section and the return section are internally tangent.

[0018] Furthermore, the straight segment is tangent to the guide segment.

[0019] Furthermore, the radius r0 of the inner profile, the length L1 of the inlet section, and the lengths L2 of the first and second inlet vertical sections are adjusted by the structure of the hydraulic retarder and the spatial constraints of the vehicle layout.

[0020] Beneficial effects:

[0021] (1) A biomimetic nautilus volute for a hydraulic retarder of the present invention has an outer profile located outside the inner profile. It is a closed curve composed of an inlet section, a first vertical inlet section, a straight section, a guide section, a return section, an inlet arc section, and a second vertical inlet section connected in sequence. The biomimetic nautilus volute improves the flow of oil inside the volute and suppresses vortex generation, thereby reducing energy loss of the oil flowing inside the volute and improving the braking response characteristics of the hydraulic retarder. Specifically, the inlet arc section of the profile can quickly and smoothly change the direction of oil flow, guiding the oil into the volute along the profile according to the expected flow state. The intersection of the inlet arc section and the return section allows the oil to flow smoothly within the biomimetic nautilus volute due to the return flow. Oil that fails to flow into the working chamber rejoins the inflow oil at a smaller angle, effectively preventing impact between the inflow and return oil, thus preventing vortex formation and energy loss. The return section is arc-shaped, which can quickly change the flow state of the oil, changing it from vertical to right-hand flow, allowing it to merge into the inflow oil. This avoids flow separation caused by abrupt curvature changes and minimizes local energy loss caused by changes in the flow state. The centers of the guide section and the return section do not coincide. This eccentric design reduces the flow area of ​​the oil as it flows along the volute profile, increasing the flow velocity and allowing the oil to flow into the working chamber of the hydraulic retarder more quickly.

[0022] (2) The present invention provides a biomimetic nautilus volute for a hydraulic retarder, wherein the inlet arc segment is tangent to the second inlet vertical segment. The tangent design can reduce the redundancy of the design and reduce the parameters required for the design.

[0023] (3) The present invention provides a biomimetic nautilus volute for a hydraulic retarder. The internal tangency of the guide section and the return section can reduce the redundancy of the design while ensuring the continuity of the flow channel and preventing vortices caused by pressure changes due to protrusions or concave areas, thereby causing energy loss. The tangency of the guide section and the straight section can reduce the redundancy of the design. The two tangent designs can achieve the technical solution with the fewest parameters.

[0024] (4) The present invention provides a biomimetic nautilus volute for a hydraulic retarder, wherein the straight section and the guide section are tangent, which can reduce the redundancy of the design and reduce the parameters required for the design.

[0025] (5) The biomimetic nautilus volute of the hydraulic retarder of the present invention has its inner profile radius r0, inlet section length L1, first inlet vertical section and second inlet vertical section length L2 adjusted by the structure of the hydraulic retarder and the space constraints of the vehicle layout. Therefore, the biomimetic nautilus volute can be applied to hydraulic retarders of various structures. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the hydraulic retarder.

[0027] Figure 2 A schematic diagram of the three-dimensional structure of an existing volute.

[0028] Figure 3 A schematic diagram of the existing volute profile;

[0029] Figure 4 This is a schematic diagram of the flow field inside an existing volute.

[0030] Figure 5 This is a three-dimensional structural diagram of the biomimetic nautilus shell of the present invention;

[0031] Figure 6 This is a schematic diagram of the biomimetic nautilus shell profile of the present invention;

[0032] Figure 7 This is a schematic diagram of the internal flow field of the biomimetic nautilus shell of the present invention;

[0033] Figure 8 Comparison of braking characteristics of hydraulic retarders with existing volutes and biomimetic nautilus volutes;

[0034] Among them, 1-inlet, 2-first inlet vertical section, 3-straight line section, 4-guide section, 5-return section, 6-inlet arc section, 7-inner profile line, 8-second inlet vertical section. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] This embodiment provides a biomimetic nautilus volute for a hydraulic retarder, such as... Figure 5 As shown, the bionic nautilus volute is a shell composed of an inner profile surface, an outer profile surface, and two side walls, with its top being the inlet. Oil enters the interior of the bionic nautilus volute from the inlet and flows along the inner wall of the bionic nautilus volute into the working chamber of the hydraulic retarder. Let the profile of the inner profile surface be the inner profile 7, and the profile of the outer profile surface be the outer profile.

[0037] The inner profile 7 is a closed circular curve with a radius of r0. The radius of the inner profile 7 is determined by the structure of the hydraulic retarder and the spatial constraints of the vehicle layout.

[0038] like Figure 6 As shown, the outer profile is located outside the inner profile 7 and is a closed curve composed of the inlet section 1, the first inlet vertical section 2, the straight section 3, the guide section 4, the return section 5, the inlet arc section 6, and the second inlet vertical section 8 connected in sequence; the incoming oil enters the biomimetic nautilus shell along the sequence of the first inlet vertical section 2, the second inlet vertical section 8, the inlet arc section 6, the guide section 4, and the return section 5, and flows there;

[0039] The first vertical segment 2 and the second vertical segment 8 of the inlet are of equal length and parallel to each other. One end of the first vertical segment 2 and the second vertical segment 8 of the inlet are perpendicularly connected to the two ends of the inlet segment 1, respectively. Figure 6 L2 represents the length of the vertical section 2 at the inlet. The length of the vertical section 2 at the inlet is determined by the structure of the hydraulic retarder and the spatial constraints of the overall vehicle layout.

[0040] In this embodiment, the biomimetic nautilus shell has an added flow guide section 4, a return flow section 5, and an inlet arc section 6 on the basis of the original outer shape.

[0041] make Figure 6 The direction of the middle entrance section 1 is horizontal, and the direction perpendicular to the entrance section 1 is vertical; Figure 6 In the diagram, L1 represents the length of the inlet segment 1, and L3 represents the vertical distance from the center of the inner profile 7 to the inlet segment 1. The length of the inlet segment 1 and the vertical distance from the center of the inner profile 7 to the inlet segment 1 are determined by the structure of the hydraulic retarder and the spatial constraints of the overall vehicle layout.

[0042] The guide section 4 is arc-shaped, and the center of the guide section 4 is located within the envelope of the inner profile 7, close to the side where the inflowing oil enters; the guide section 4 adopts an eccentric design, and its center does not coincide with the center of the inner profile 7. Figure 6 In the diagram, r2 represents the radius of the guide section 4, and e1 and e2 represent the horizontal and vertical distances between the center of the guide section 4 and the center of the inner profile 7, respectively. The eccentric design can reduce the flow area of ​​the oil during the flow along the biomimetic nautilus volute profile, and can increase the flow velocity of the oil, so that the oil flows into the working chamber of the hydraulic retarder faster.

[0043] The straight segment 3 connects the first inlet vertical segment and the guide segment 4; the straight segment 3 and the first inlet vertical segment share an endpoint, which can ensure the continuity of the profile of the biomimetic nautilus volute; the straight segment 3 is also tangent to the guide segment 4, and the tangent design can reduce the redundancy when designing the profile and reduce the parameters required to design the biomimetic nautilus volute.

[0044] like Figure 6As shown, the return section 5 is arc-shaped, and its center is located within the envelope of the inner profile 7, close to the opposite side where the incoming oil enters. The arc-shaped structure of the return section 5 can quickly change the flow state of the oil, changing the flow from vertical to rightward, so that the return oil can merge into the incoming oil, thereby avoiding flow separation caused by sudden curvature changes and minimizing local energy loss caused by changes in the flow state of the oil. The return section 5 adopts an eccentric design, and its center does not coincide with the center of the inner profile 7. The eccentric design allows the oil to flow into the working chamber of the hydraulic retarder more quickly. Figure 6 In the diagram, a1 and a2 represent the horizontal and vertical distances between the center of the return flow section 5 and the center of the guide flow section 4, respectively. In this embodiment, the return flow section 5 and the guide flow section 4 are internally tangent. The internal tangent design of the return flow section 5 and the guide flow section 4 can ensure the continuity of the flow channel, prevent vortices caused by pressure changes due to protruding corners or concave areas from causing energy loss, and also reduce the redundancy of the design.

[0045] One end of the inlet arc segment 6 intersects with the return segment 5, that is, the other end of the inlet arc segment 6 shares an endpoint with the second inlet vertical segment; the concave surface of the arc of the inlet arc segment 6 faces the straight segment 3; the included angle formed by the arc segment 6 and the return segment 5 does not abut against the inner profile line 7; Figure 6 In this context, r1 represents the radius of the inlet arc segment 6. The inlet arc segment 6 can quickly and smoothly change the direction of oil flow, guiding the oil into the volute along the profile according to the expected flow state. The return segment 5 and the inlet arc segment 6 enable the oil flowing back in the biomimetic nautilus volute to rejoin the inflow oil at a small angle (the angle formed between the velocity of the oil at the inlet and the velocity of the returning oil). This effectively avoids impact between the inflow and return oil, thus preventing the formation of vortices. In this embodiment, the inlet arc segment 6 is tangent to the inlet vertical segment 2. This tangent design reduces design redundancy and the number of parameters required for the design.

[0046] In this embodiment, the biomimetic nautilus shell reduces the design parameters to 10 through tangential design, namely: L1, L2, L3, r0, r1, r2, a1, a2, e1, and e2.

[0047] Working principle:

[0048] The biomimetic nautilus shell in this embodiment is an optimization of the existing shell structure, to... Figure 5 For example, Figure 5From the perspective of the rotating impeller of the hydraulic retarder, the rotation direction is clockwise. Under the dynamic action of the rotating impeller, most of the oil entering the volute also moves in a clockwise direction. In this embodiment, the biomimetic nautilus volute has an inlet arc section 6 at the inlet. The inlet arc section 6 causes the incoming oil to move to the right, preventing some of the incoming oil from entering to the left and impacting the returning oil. The oil enters the guide section 4 along the straight section 3. The guide section 4 adopts an eccentric design to reduce the flow area of ​​the oil and accelerate the flow rate of the oil. The oil enters the working chamber of the hydraulic retarder more quickly; the oil passes through the guide section 4 and enters the return section 5. The return section 5 is also arc-shaped and tangent to the guide section 4. This tangential design ensures the continuity of the flow channel and prevents the generation of vortices. Furthermore, the intersection of the return section 5 and the inlet arc section 6 reduces the impact between the returning oil at the return section 5 and the incoming oil flowing from the inlet arc section 6, allowing the returning oil to rejoin the incoming oil. This suppresses vortex generation, reduces energy loss in the internal flow, and thus achieves the braking response characteristics of the hydraulic retarder. Figure 7 As shown, the biomimetic nautilus shell in this embodiment does not generate a large area of ​​vortex region inside.

[0049] The experimental results of simulating and comparing the biomimetic nautilus casing in this embodiment with existing casings in a hydraulic retarder are as follows: Figure 8 And as shown in the table below:

[0050] Inlet and outlet pressure difference (Pa) <![CDATA[Maximum oil velocity (v max , m / s)]]> Existing volute 1766.6 4.8937 In this embodiment, a biomimetic nautilus shell is used. 955.23 6.6536

[0051] The simulation comparison test utilized computational fluid dynamics (CFD) simulation technology and, under the same operating conditions, simulated the braking characteristics of hydraulic retarders with existing volutes and biomimetic nautilus volutes; the rotational speeds of the two hydraulic retarders in the simulation comparison test were the same.

[0052] As shown in Table 1, the inlet and outlet pressure difference of the hydraulic retarder with the bionic nautilus volute is lower than that of the hydraulic retarder with the existing volute. Therefore, the bionic nautilus volute can reduce internal flow resistance, thereby reducing energy loss inside the volute. In addition, the maximum oil velocity of the hydraulic retarder with the bionic nautilus volute is greater than that of the hydraulic retarder with the existing volute. Therefore, the bionic nautilus volute can allow the oil to flow into the working chamber of the hydraulic retarder more quickly, resulting in better torque response characteristics of the hydraulic retarder.

[0053] The braking response characteristics of a hydraulic retarder include: maximum braking torque and onset time, where onset time refers to the time it takes for the hydraulic retarder to begin filling with fluid (corresponding to...). Figure 8 The total time taken from time t0 in the equation to reaching the maximum braking torque; Figure 8It includes braking torque and drive wheel speed data for two types of hydraulic retarders, where the original volute is the existing volute, and the biomimetic volute is the biomimetic nautilus volute in this embodiment; such as Figure 8 As shown, compared with the hydraulic retarder with the existing volute, the hydraulic retarder with the biomimetic nautilus volute in this embodiment has a 6.15% increase in maximum braking torque and a 6.58% reduction in start-up time, indicating that the biomimetic nautilus volute in this embodiment has a better optimization effect on the braking response characteristics of the hydraulic retarder.

[0054] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A biomimetic nautilus shell for a hydraulic retarder, characterized in that, The biomimetic nautilus shell includes: inner shaped surfaces and outer shaped surfaces; Let the profile lines of the inner profile surface be called inner profile lines, and the profile lines of the outer profile surface be called outer profile lines; the inner profile line is a closed circular curve with a radius of r0; The outer profile is located outside the inner profile and is a closed curve composed of an inlet segment, a first inlet vertical segment, a straight segment, a guide segment, a return segment, an inlet arc segment, and a second inlet vertical segment connected in sequence. The inlet arc segment is tangent to the second inlet vertical segment, the guide segment is internally tangent to the return segment, and the straight segment is tangent to the guide segment. The lengths of the first and second inlet vertical segments are both L2. Let the direction of the inlet segment be the horizontal direction, and the direction perpendicular to the inlet segment be the vertical direction. The length of the inlet segment is L1, and the vertical distance between the inlet segment and the center of the inner profile is L3. Both the guide section and the return section are arc-shaped; the centers of the guide section and the return section do not coincide, and both are located within the envelope of the inner profile line but do not coincide with the center of the inner profile line; the radius of the guide section is r2, the horizontal distance between the center of the guide section and the inner profile line is e1, and the vertical distance is e2; the horizontal distance between the center of the return section and the guide section is a1, and the vertical distance is a2. The radius of the inlet arc segment is r1, and the concave surface of the arc faces the straight line segment; the angle formed by the inlet arc segment and the return segment does not collide with the inner profile line; L1, L2, L3, r0, r1, r2, a1, a2, e1, and e2 determine the outer shape lines of the biomimetic nautilus shell; The incoming oil flows into the biomimetic nautilus shell in the following order: the first vertical inlet section, the second vertical inlet section, the inlet arc section, the guide section, and the return section; The guide section is located on the side near the inlet of the oil, and the return section is located on the opposite side near the inlet of the oil.

2. The biomimetic nautilus shell of a hydraulic retarder as described in claim 1, characterized in that, The radius r0 of the inner profile, the length L1 of the inlet section, and the lengths L2 of the first and second inlet vertical sections are adjusted by the structure of the hydraulic retarder and the spatial constraints of the vehicle layout.

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