Method for designing a volute flow channel of a turbocharger

Abstract

The application relates to a turbine housing flow channel design method of a turbocharger and relates to the technical field of turbochargers. The method comprises the following steps: determining a rotating shaft corresponding to the turbine housing flow channel, a rotating direction, an initial key cross-section area and an initial cross-section position; determining a first cross-section set corresponding to the turbine housing flow channel; determining a second cross-section set corresponding to the turbine housing flow channel; determining the cross-section position and the cross-section area of all key cross sections corresponding to the turbine housing flow channel; and generating the turbine housing flow channel. In the process of designing the turbine housing flow channel, the fluid entering the turbine housing flow channel has a linearly changed area distribution in the flow channel corresponding to the first function, and when entering the flow channel corresponding to the second segment function, the area distribution can be adjusted in the form of a quadratic function to change the flow, thereby changing the pressure distribution, reducing the total excitation amplitude of the turbine housing outlet (i.e. the turbine inlet) in the operating condition range, effectively reducing the high-cycle fatigue risk and improving the reliability of the turbine housing.

Description

Technical Field

[0001] This application relates to the field of turbocharger technology, and in particular to a turbocharger volute flow channel design method. Background Technology

[0002] A turbocharger uses engine exhaust gases to drive a turbine, which in turn powers a coaxial impeller, providing the internal combustion engine with greater intake pressure. The turbocharger turbine housing flow channel primarily alters the trajectory of the exhaust gas from the exhaust manifold through vortex flow paths, providing a matched initial velocity field to the turbine at the turbine housing outlet. Ideally, the matching between the turbine housing and the turbine should achieve the turbine's initial ideal injection angle; however, limitations in space, structure, and losses often result in deviations from this ideal value. The aerodynamic performance of turbochargers and the reliability of the turbine housing assembly have always been crucial aspects of turbine research. As the engine and turbocharger operate, the load on the impeller constantly changes, leading to fatigue issues. Ideally, the airflow within the turbine housing should be distributed as uniformly as possible upon reaching the turbine inlet (i.e., turbine housing outlet) section. This reduces pressure fluctuations, helps minimize excitation-induced vibrations, lowers fatigue levels, and improves the overall reliability of the turbocharger. To ensure a uniform mass flow rate distribution of exhaust gas after passing through the vortex channel, the channel is designed with a tapering shape. The vortex begins near the inlet at the point of maximum cross-sectional area, and ends at the point of minimum cross-sectional area along the 360° circumferential flow. A vortex tongue is formed at the junction of the maximum and minimum cross-sectional areas. The number of turbine blades is finite, and the flow is not uniform across different angular phases, exhibiting a periodic variation. During this periodic variation, the blades are most affected by the vortex tongue. Since the fluid before the vortex tongue has no radial velocity, while the fluid after the vortex tongue has radial velocity, the fluid velocity at this location changes significantly, resulting in pressure fluctuations, which in turn excite the turbine during operation. Reducing harmonic excitation values ​​through the initial design of the flow channel is the most economical, effective, and least performance-impacting method.

[0003] In current flow channel design, the cross-sectional area of ​​the flow channel is represented by A, and r represents the centroid of the flow channel cross-section. The ratio of the flow channel cross-sectional area distribution to the centroid is defined as A / r. The surface-to-diameter ratio A / r is used to characterize the variation law of the surface-to-diameter ratio of the entire flow channel, as shown in Formula 1 below:

[0004] Formula 1:

[0005] In the formula, angle represents the angle formed between the measured section and the initial section, with the section rotation axis as the included node after setting the initial section cross-section; A represents the cross-sectional area of ​​the section corresponding to the angle; A0 represents the cross-sectional area of ​​the initial section cross-section; r represents the position of the centroid of the section corresponding to the angle; and r0 represents the centroid of the initial section cross-section. In typical designs, since linear control of A / r is quite complex, the flow channel design can also follow the principle that the area A is linearly distributed.

[0006] In related technologies, for dual-channel volutes, pressure fluctuations can be changed and excitation values ​​reduced by misaligning the throat or machining the partition wall. However, for single-channel turbocharger volutes, it is difficult to reduce the excitation amplitude using traditional methods due to the limitation of having only one throat and very little margin for subsequent tool machining. Summary of the Invention

[0007] This application relates to a turbocharger volute flow channel design method, which can effectively reduce the risk of high-cycle fatigue and improve the reliability of the volute by setting the cross-sectional area of ​​the volute flow channel. The method includes:

[0008] Determine the rotation axis, rotation direction, initial critical section area, and initial section position corresponding to the vortex flow channel;

[0009] Based on the variation law of the first cross section and the area of ​​the initial key cross section, a set of first cross sections corresponding to the vortex shell flow channel is determined. The set of first cross sections includes at least two key cross sections. Each key cross section has a corresponding cross section position and cross section area. The first key cross section in the set of first cross sections is the initial cross section, and the cross section area of ​​the first key cross section is the initial key cross section area. Starting from the second key cross section, with the rotation axis as the angle vertex, the clockwise angle between each key cross section and the adjacent previous key cross section is 1°. Each key cross section has a key cross section number. The area of ​​the key cross section in the set of first cross section areas conforms to a linear function with the key cross section number.

[0010] Based on the variation law of the second cross section and the cross-sectional area of ​​the last critical cross section in the first cross section set, a second cross section set corresponding to the vortex flow channel is determined. The second cross section set includes at least two critical cross sections. The sum of the number of cross sections in the first cross section set and the second cross section set is 361. The first critical cross section in the second cross section set is a cross section with the rotation axis as the included vertex and a clockwise angle of 1° with the last critical cross section in the first cross section set. Starting from the second critical cross section, with the rotation axis as the included vertex, each critical cross section has a clockwise angle of 1° with the adjacent previous critical cross section. The sequence number of the first critical cross section in the second cross section set is adjacent to the sequence number of the last critical cross section in the first cross section set, and the area of ​​the critical cross section in the second cross section area set conforms to a quadratic function with the sequence number of the critical cross section.

[0011] Based on the first set of cross-sections and the second set of cross-sections, determine the cross-sectional positions and cross-sectional areas of all key cross-sections corresponding to the vortex flow channel;

[0012] Based on the cross-sectional positions and cross-sectional areas of all key cross-sections corresponding to the vortex flow channel, and in conjunction with production parameters, the vortex flow channel is generated. In the vortex flow channel, the cross-sectional area distribution pattern between two adjacent key cross-sections conforms to either a first cross-sectional variation pattern or a second cross-sectional variation pattern.

[0013] In an optional embodiment, determining the first set of cross-sections corresponding to the vortex flow channel based on the first cross-section variation law and the initial key cross-sectional area includes:

[0014] Determine the cross-sectional area of ​​the initial critical section of the vortex flow channel and the cross-sectional area of ​​the final critical section of the vortex flow channel, wherein the initial critical section of the vortex flow channel coincides with the final critical section of the vortex flow channel.

[0015] The variation law of the first cross section is determined based on the initial critical cross section area and the cross section area of ​​the last critical cross section of the vortex flow channel;

[0016] The set of first cross sections corresponding to the vortex flow channel is determined based on the variation law of the first cross section.

[0017] In an optional embodiment, the variation law of the first cross-section is as follows:

[0018]

[0019] In the formula, n is the sequence number of the critical section, An is the area of ​​the critical section corresponding to the sequence number, A0 is the cross-sectional area of ​​the initial critical section of the vortex flow channel, and A360 is the cross-sectional area of ​​the final critical section of the vortex flow channel.

[0020] In an optional embodiment, determining the second set of cross-sections corresponding to the vortex flow channel based on the variation law of the second cross-section and the cross-sectional area of ​​the last critical cross-section in the first set of cross-sections includes:

[0021] The cross-sectional area of ​​the initial critical section in the second cross-section set is determined based on the cross-sectional area of ​​the last critical section in the first cross-section set.

[0022] Determine the area of ​​the largest critical section in the second section set;

[0023] The variation law of the second section is determined based on the initial critical section area in the second section set and the maximum critical section area in the second section set;

[0024] The set of second cross sections corresponding to the vortex shell flow channel is determined based on the variation law of the second cross section.

[0025] In an optional embodiment, the variation law of the second cross section is as follows:

[0026] A n =c*(nd) 2 +e

[0027] Wherein, c is determined based on the area of ​​the initial key cross section in the second cross section set, the area of ​​the last key cross section of the vortex flow channel, and the value of d;

[0028] d indicates the index of the critical section with the largest area in the second section set;

[0029] e indicates the area of ​​the critical section with the largest area in the second set of sections.

[0030] In an optional embodiment, c is a negative value.

[0031] In an optional embodiment, the key section with the largest area in the second set of sections is numbered 345.

[0032] In an optional embodiment, the area of ​​the critical section with the largest area in the second set of sections is 1.04 to 1.2 times the area of ​​the initial critical section in the second set of sections.

[0033] In an optional embodiment, generating the vortex flow channel based on the cross-sectional positions and cross-sectional areas of all key cross-sections corresponding to the vortex flow channel, combined with production parameters, includes:

[0034] Based on the cross-sectional positions and cross-sectional areas of all key cross-sections corresponding to the vortex flow channel, the cross-sectional area distribution pattern between two adjacent key cross-sections is determined.

[0035] Based on the aforementioned cross-sectional area distribution pattern, an initial vortex shell flow channel is generated;

[0036] Based on the cross-sectional area of ​​the initial critical section of the vortex flow channel and the cross-sectional area of ​​the final critical section of the vortex flow channel, the contact surface of the initial critical section and the final critical section of the initial vortex flow channel is adjusted to obtain the vortex flow channel.

[0037] The beneficial effects of the technical solution provided in this application include at least the following:

[0038] In the process of designing the volute flow channel, the cross-sectional area variation law of the volute flow channel is set to conform to a piecewise function form, with the first segment conforming to a linear function and the second segment conforming to a quadratic function. Under this condition, when the fluid entering the volute flow channel flows through the flow channel corresponding to the second segment of the piecewise function, it can achieve flow rate adjustment in the flow channel that changes in the form of a quadratic function, thereby changing the pressure distribution. This, together with the pressure distribution generated by the fluid in the first segment cross-section set, constitutes the pressure distribution around the volute outlet (i.e., turbine inlet) for 360°. This pressure distribution form can obtain a lower excitation amplitude within the engine operating condition range, effectively reducing the risk of high-cycle fatigue and improving the reliability of the volute. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A schematic diagram of a vortex flow channel provided in an exemplary embodiment of this application is shown.

[0041] Figure 2 A schematic flowchart of a turbocharger volute flow channel design method provided in an exemplary embodiment of this application is shown.

[0042] Figure 3 This illustration shows a schematic diagram of the relationship between an angle and a cross-sectional area provided by an exemplary embodiment of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0044] This application provides a design method for a volute flow channel. The volute flow channel obtained based on the design method of this application is an ideal volute flow channel. In actual production, the volute flow channel entity that conforms to the design logic will be processed based on the design method provided in this application. That is, this application provides a process for designing an ideal volute flow channel. After designing the volute flow channel using this design method, the volute flow channel can be fabricated by combining it with technologies such as 3D printing.

[0045] Figure 1 This illustration shows a schematic diagram of a vortex flow channel provided in an exemplary embodiment of this application. Please refer to... Figure 1 This volute flow channel is an ideal volute flow channel that incorporates actual process parameters. Please refer to... Figure 1 The key features of this vortex flow channel include a rotation axis 110, a rotation direction 120, an initial critical section 130, and a final critical section 140. The initial critical section 130 and the final critical section 140 are coplanar, but their corresponding actual areas are different. Therefore, in the vortex flow channel, a significant area change can be clearly seen at the coplanar points of the initial critical section 130 and the final critical section 140. In this embodiment, the vortex flow channel can be divided into numerous sections. During the operation of the vortex flow channel, the change in the area of ​​the cross-section will provide a velocity excitation to the fluid within the channel. This velocity excitation will cause a change in the fluid velocity, thereby causing a change in the instantaneous flow rate of the fluid passing through the corresponding cross-section. This embodiment provides such a... Figure 1 The design process of the vortex flow channel is shown.

[0046] Figure 2 This application illustrates a flowchart of a turbocharger volute flow channel design method according to an exemplary embodiment, which is used to design, for example... Figure 1 Taking the turbocharger shown as an example, the method includes:

[0047] Step 201: Determine the rotation axis, rotation direction, initial key cross-sectional area, and initial cross-sectional position corresponding to the vortex flow channel.

[0048] In this process, the rotation axis, rotation direction, initial critical section area, and initial section position for establishing the vortex flow channel will be determined. Optionally, after determining the initial critical section position, the initial critical section position and the final critical section position of the vortex flow channel can be determined simultaneously. In some embodiments, since the two are coplanar, the final critical section area of ​​the vortex flow channel will also be determined.

[0049] Step 202: Based on the variation law of the first cross section and the area of ​​the initial key cross section, determine the set of the first cross sections corresponding to the vortex shell flow channel.

[0050] In this embodiment, the first set of cross-sections includes at least two key cross-sections. Each key cross-section corresponds to a cross-section position and a cross-sectional area. The first key cross-section in the first set is the key cross-section itself, and its area is the initial key cross-section area. Starting from the second key cross-section, with the rotation axis as the angle vertex, each key cross-section forms a clockwise angle of 1° with its adjacent preceding key cross-section. Each key cross-section has a corresponding key cross-section number. The area of ​​each key cross-section in the first set of cross-section areas conforms to a linear function with its key cross-section number. It should be noted that the included angle shown in this embodiment is...

[0051] In some embodiments, the process of determining the first cross-section set includes: first, determining the cross-sectional area of ​​the initial critical cross-section of the vortex flow channel and the cross-sectional area of ​​the final critical cross-section of the vortex flow channel, wherein the initial critical cross-section of the vortex flow channel coincides with the final critical cross-section of the vortex flow channel; determining the variation law of the first cross-section based on the cross-sectional area of ​​the initial critical cross-section and the cross-sectional area of ​​the final critical cross-section of the vortex flow channel; and finally, determining the first cross-section set corresponding to the vortex flow channel based on the variation law of the first cross-section.

[0052] In one example, the final determined variation law of the first cross section is shown in Formula 2 below:

[0053] Formula 2:

[0054] In the formula, n is the sequence number of the critical section, An is the area of ​​the critical section corresponding to the sequence number, A0 is the cross-sectional area of ​​the initial critical section of the vortex flow channel, and A360 is the cross-sectional area of ​​the final critical section of the vortex flow channel. As can be seen from Formula 2, after the initial critical section, the area of ​​each subsequent cross-section is smaller than the cross-sectional area of ​​the initial critical section.

[0055] Step 203: Based on the variation law of the second cross section and the cross-sectional area of ​​the last critical cross section in the first cross section set, determine the second cross section set corresponding to the vortex shell flow channel.

[0056] In this embodiment, the second section set includes at least two key sections, and the sum of the number of sections in the first section set and the second section set is 361. In one example, the first section set has a total of 341 key sections, denoted as A0 to A340, and the second section set includes 20 key sections, denoted as A341 to A360, and each section between A340 and A341 conforms to the variation rule of the second section.

[0057] The first critical section in the second section set is a section with the rotation axis as the angular vertex, which forms a clockwise angle of 1° with the last critical section in the first section set. Starting from the second critical section, with the rotation axis as the angular vertex, each critical section forms a clockwise angle of 1° with the adjacent previous critical section. The index of the first critical section in the second section set is adjacent to the index of the last critical section in the first section set, and the area of ​​the critical sections in the second section area set conforms to a quadratic function with the index of the critical sections.

[0058] In some embodiments, the second section set is generated as follows: the cross-sectional area of ​​the initial critical section in the second section set is determined based on the cross-sectional area of ​​the last critical section in the first section set; the maximum critical section area in the second section set is determined; the variation law of the second section is determined based on the initial critical section area and the maximum critical section area in the second section set; and the second section set corresponding to the vortex shell channel is determined based on the variation law of the second section.

[0059] In one example, the final determined variation law of the second cross section is shown in Formula 3 below:

[0060] Formula 3: A n =c*(nd) 2 +e

[0061] In the formula, c is determined based on the area of ​​the initial critical section in the second section set, the area of ​​the last critical section of the vortex casing channel, and the value of d, and c is negative; d indicates the index of the critical section with the largest area in the second section set; e indicates the area of ​​the critical section with the largest area in the second section set. In an optional embodiment, the index of the critical section with the largest area in the second section set is 345. In an optional embodiment, the area of ​​the critical section with the largest area in the second section set is 1.04 to 1.2 times the area of ​​the initial critical section in the second section set.

[0062] Step 204: Based on the first set of cross-sections and the second set of cross-sections, determine the cross-sectional positions and cross-sectional areas of all key cross-sections corresponding to the vortex flow channel.

[0063] In this case, combining Formula 2 and Formula 3, that is, the first set of cross-sections and the second set of cross-sections, we can determine that the cross-sectional area of ​​all cross-sections corresponding to the vortex shell flow channel should conform to Formula 4, the piecewise function:

[0064] Formula 4:

[0065] Based on Formula 4, the numerical calculation of c is shown in Formula 5 below:

[0066] Formula 5:

[0067] In one example, the value of k can be 1.04, and in another example, the value of k can be 1.2. In this embodiment, the value of k will be determined according to actual needs.

[0068] In one example, the cross-sectional area distribution of the vortex flow channel is as follows: Figure 3 As shown. Figure 3 The variation of the cross-sectional area 320 with the increase of the angle 310 is shown.

[0069] It should be noted that the embodiments of this application only show one possible segmentation method. In other embodiments of this application, the sequence number of the last critical section in the first section set can be any number from 320 to 340.

[0070] Step 205: Based on the cross-sectional positions and cross-sectional areas of all key sections corresponding to the vortex flow channel, and in conjunction with production parameters, generate the vortex flow channel.

[0071] In this embodiment, the cross-sectional area distribution between two adjacent critical sections in the vortex flow channel conforms to either a first cross-sectional variation law or a second cross-sectional variation law. It should be noted that when handling the coplanarity of the initial critical section and the final critical section of the vortex flow channel, the actual cross-section is generated based on the area difference between the initial and final critical sections.

[0072] In summary, the method provided in this application, during the design of the volute flow channel, sets the cross-sectional area variation law of the volute flow channel to conform to a piecewise function, with the first segment conforming to a linear function and the second segment conforming to a quadratic function. Under this condition, when the fluid entering the volute flow channel flows through the flow channel corresponding to the second segment of the piecewise function, it can achieve flow rate adjustment in the flow channel that changes in the form of a quadratic function, thereby changing the pressure distribution. This, together with the pressure distribution generated by the fluid in the first cross-sectional set, constitutes the pressure distribution around the volute outlet (i.e., the turbine inlet) for 360°. This pressure distribution form can achieve a lower excitation amplitude within the engine operating condition range, effectively reducing the risk of high-cycle fatigue and improving the reliability of the volute.

[0073] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for designing the volute flow channel of a turbocharger, characterized in that, The method includes: Determine the rotation axis, rotation direction, initial critical section area, and initial section position corresponding to the vortex flow channel; Based on the variation law of the first cross section and the area of ​​the initial key cross section, a set of first cross sections corresponding to the vortex shell flow channel is determined. The first set of cross sections includes at least two key cross sections. Each key cross section has a corresponding cross section position and cross section area. The first key cross section in the first set of cross sections is the initial cross section, and the cross section area of ​​the first key cross section is the initial key cross section area. Starting from the second key cross section, with the rotation axis as the angle vertex, the clockwise angle between each key cross section and the adjacent previous key cross section is 1°. Each key cross section has a key cross section number. The area of ​​the key cross section in the first set of cross sections and the key cross section number conform to a linear function. Based on the variation law of the second cross section and the cross-sectional area of ​​the last critical cross section in the first cross section set, a second cross section set corresponding to the vortex flow channel is determined. The second cross section set includes at least two critical cross sections. The sum of the number of cross sections in the first cross section set and the second cross section set is 361 (0~360). The first critical cross section in the second cross section set is a cross section with the rotation axis as the included vertex and a clockwise angle of 1° with the last critical cross section in the first cross section set. Starting from the second critical cross section, with the rotation axis as the included vertex, each critical cross section has a clockwise angle of 1° with the adjacent previous critical cross section. The sequence number of the first critical cross section in the second cross section set is adjacent to the sequence number of the last critical cross section in the first cross section set, and the area of ​​the critical cross section in the second cross section set conforms to a quadratic function with the sequence number of the critical cross section. Based on the first set of cross-sections and the second set of cross-sections, determine the cross-sectional positions and cross-sectional areas of all key cross-sections corresponding to the vortex flow channel; Based on the cross-sectional positions and cross-sectional areas of all key cross-sections corresponding to the vortex flow channel, and combined with production parameters, the vortex flow channel is generated. In the vortex flow channel, the cross-sectional area distribution pattern between two adjacent key cross-sections conforms to the first cross-sectional variation pattern or the second cross-sectional variation pattern. The variation pattern of the first cross section is as follows: ； In the formula, n is the index of the critical section, and A n A0 is the area of ​​the critical section corresponding to the serial number, and A0 is the cross-sectional area of ​​the initial critical section of the vortex casing flow channel. 360 The cross-sectional area of ​​the final critical section of the vortex flow channel; The variation pattern of the second cross section is as follows: ； Wherein, c is determined based on the area of ​​the initial key section in the second section set, the area of ​​the last key section of the vortex flow channel, and the value of d; d indicates the index of the critical section with the largest area in the second section set; e indicates the area of ​​the critical section with the largest area in the second set of sections.

2. The method according to claim 1, characterized in that, The determination of the first cross-section set corresponding to the vortex shell flow channel based on the first cross-section variation law and the initial key cross-section area includes: Determine the cross-sectional area of ​​the initial critical section of the vortex flow channel and the cross-sectional area of ​​the final critical section of the vortex flow channel, wherein the initial critical section of the vortex flow channel coincides with the final critical section of the vortex flow channel. The variation law of the first cross section is determined based on the initial critical cross section area and the cross section area of ​​the last critical cross section of the vortex flow channel; The set of first cross sections corresponding to the vortex flow channel is determined based on the variation law of the first cross section.

3. The method according to claim 1, characterized in that, The determination of the second section set corresponding to the vortex flow channel based on the variation law of the second section and the cross-sectional area of ​​the last critical section in the first section set includes: The cross-sectional area of ​​the initial critical section in the second cross-section set is determined based on the cross-sectional area of ​​the last critical section in the first cross-section set. Determine the area of ​​the largest critical section in the second section set; The variation law of the second section is determined based on the initial critical section area in the second section set and the maximum critical section area in the second section set; The set of second cross sections corresponding to the vortex shell flow channel is determined based on the variation law of the second cross section.

4. The method according to claim 1, characterized in that, The value of c is negative.

5. The method according to claim 1, characterized in that, In the second set of cross-sections, the key cross-section with the largest area is numbered 345.

6. The method according to claim 1, characterized in that, In the second set of cross-sections, the area of ​​the critical cross-section with the largest area is 1.04 to 1.2 times the cross-sectional area of ​​the initial critical cross-section in the second set of cross-sections.

7. The method according to claim 1, characterized in that, The process of generating the vortex flow channel based on the cross-sectional positions and areas of all key cross-sections corresponding to the vortex flow channel, combined with production parameters, includes: Based on the cross-sectional positions and cross-sectional areas of all key cross-sections corresponding to the vortex flow channel, the cross-sectional area distribution pattern between two adjacent key cross-sections is determined. Based on the aforementioned cross-sectional area distribution pattern, an initial vortex shell flow channel is generated; Based on the cross-sectional area of ​​the initial critical section of the vortex flow channel and the cross-sectional area of ​​the final critical section of the vortex flow channel, the contact surface of the initial critical section and the final critical section of the initial vortex flow channel is adjusted to obtain the vortex flow channel.

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