A ramjet fuel pump hole-shaft matching method and system

Abstract

A ramjet fuel pump hole-shaft matching method, the ramjet fuel pump includes a gear pump, a gear shaft, and a sliding bearing, including: obtaining the design point parameters of the fuel pump and the selected materials of the gear pump; calculating the output power, torque, the minimum shaft diameter corresponding to the gear shaft under the load condition of the gear pump output power, the width of the sliding bearing, and the circumferential speed of the gear shaft shaft diameter position; obtaining the working pressure of the oil film in the gear shaft shaft diameter gap through the hydraulic pressure and meshing force generated by the gear meshing during the operation of the gear pump; obtaining the working pressure of the gear shaft bearing surface according to the working pressure of the oil film in the gear shaft shaft diameter gap; calculating the gear bearing load coefficient; obtaining the fuel pump hole-shaft matching clearance value according to the gear bearing load coefficient. This application can shorten the engineering cycle, reduce the design cost, and ensure the high-speed operation stability and efficiency of the fuel pump.

Description

Technical Field

[0001] The present application relates to the field of ramjet fuel supply systems, and in particular to a ramjet fuel pump hole-shaft matching method and system. Background Art

[0002] The fuel pump is the core component of the ramjet engine. Increasing the speed of the fuel pump is the most effective way to reduce the system power and battery weight. Therefore, the speed of the high-power fuel pump has become one of the bottlenecks restricting the lightweight design of the engine. However, the fuel pump will bring a series of problems under high power and high speed, such as severe wear and low efficiency. In order to ensure the reliability of the fuel pump under high power and high speed, it is necessary to reasonably design the hole-shaft matching relationship between the gear shaft and the inner diameter of the sliding bearing at high speed.

[0003] In the prior art, the hole-shaft clearance between the gear shaft and the inner diameter of the sliding bearing is continuously determined and adjusted through engineering experience, testing, debugging, and other processes to obtain the best value. However, this process has a long engineering cycle, requires more time and energy for continuous trial and error, and has high sunk costs. Summary of the invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present application provides a ramjet engine fuel pump hole-shaft matching method and system.

[0005] In a first aspect, the present application provides a method for matching a ramjet engine fuel pump hole and shaft, wherein the ramjet engine fuel pump comprises a gear pump, a gear shaft, and a sliding bearing, and is characterized in that it comprises:

[0006] Obtain the design point parameters of the fuel pump and the selected materials of the gear pump;

[0007] Calculate the output power, torque, the minimum shaft diameter, the width of the sliding bearing and the circumferential speed of the gear shaft at the shaft diameter position corresponding to the gear shaft under the output power load of the gear pump according to the design point parameters of the fuel pump and the yield point stress and the allowable shear stress of the material selected for the gear pump;

[0008] The working pressure of the oil film in the gear shaft diameter clearance is obtained through the hydraulic pressure and meshing force generated by the gear meshing during the operation of the gear pump;

[0009] According to the working pressure borne by the oil film in the axial diameter gap of the gear shaft, the working pressure on the gear shaft bearing surface is obtained;

[0010] The gear bearing load coefficient is calculated based on the minimum shaft diameter of the gear shaft under the condition of the output power load of the gear pump, the width of the sliding bearing, the circumferential speed of the gear shaft shaft diameter position, the working pressure of the gear shaft bearing surface and the dynamic viscosity of the working medium of the gear pump;

[0011] According to the gear bearing load coefficient, the fuel pump hole-shaft matching clearance value is obtained.

[0012] Preferably, the calculation of the output power, torque, the minimum shaft diameter, the sliding bearing width and the circumferential speed of the gear shaft at the shaft diameter position corresponding to the gear shaft under the condition of the output power load of the gear pump according to the design point parameters of the fuel pump and the yield point stress and the allowable shear stress of the material selected for the gear pump includes:

[0013] The design point parameters of the gear pump include: design speed n, flow rate Q, and pressure difference ΔP before and after the pump;

[0014] Gear pump material yield point stress and allowable shear stress [τ];

[0015] Gear pump output power P c =Q·ΔP;

[0016] Torque

[0017] The minimum shaft diameter of the gear shaft under the condition of bearing the output power load of the gear pump

[0018] Circumferential speed of the gear shaft at the axial diameter position:

[0019] n is the rotation speed;

[0020] The width B of the sliding bearing is calculated based on the width-to-diameter ratio B / d=1.1.

[0021] Preferably, the working pressure borne by the oil film in the axial diameter clearance of the gear shaft is obtained by the hydraulic pressure and meshing force generated by the meshing of the gears during the operation of the gear pump, including:

[0022] The hydraulic pressure F generated by the gear meshing during the operation of the gear pump i =aΔPbd d , a calculation coefficient, b gear width, d d Tip diameter;

[0023] Meshing force:

[0024] Working pressure F borne by the oil film in the gear shaft diameter clearance Σ =F i +F n .

[0025] Preferably, the working pressure on the gear shaft bearing surface is obtained according to the working pressure borne by the oil film in the gear shaft axial diameter clearance, including:

[0026] Gear shaft bearing surface working pressure

[0027] Preferably, the gear bearing load coefficient is calculated based on the minimum shaft diameter corresponding to the gear shaft under the condition of the output power load of the gear pump, the width of the sliding bearing, the circumferential speed of the gear shaft shaft diameter position, the working pressure on the gear shaft bearing surface, and the dynamic viscosity of the gear pump working medium, including:

[0028] Relative clearance value of hole-shaft fit ψ;

[0029] Gear bearing load factor Dynamic viscosity η of the working medium of the gear pump.

[0030] Preferably, the fuel pump hole-shaft clearance value is obtained according to the gear bearing load coefficient, including:

[0031] According to the gear bearing load coefficient Cp and the aspect ratio B / d value, the eccentricity χ is obtained;

[0032] By formula Get the fuel pump hole-shaft clearance value.

[0033] Preferably, the working pressure P on the gear shaft bearing surface is used to verify whether the values ​​of the gear shaft minimum shaft diameter d and the gear width b are reasonable;

[0034] If the working pressure P on the gear shaft bearing surface is greater than a critical value, the minimum shaft diameter d of the gear shaft and the gear width b are re-determined.

[0035] In a second aspect, the present application provides a ramjet engine fuel pump hole-shaft matching method and system, characterized by comprising:

[0036] The acquisition module is used to obtain the design point parameters of the fuel pump and the selected materials of the gear pump;

[0037] The first calculation module is used to calculate the output power, torque, the minimum shaft diameter, the width of the sliding bearing and the circumferential speed of the gear shaft shaft diameter position corresponding to the gear shaft under the condition of the output power load of the gear pump according to the design point parameters of the fuel pump and the yield point stress and the allowable shear stress of the material selected for the gear pump;

[0038] The second calculation module is used to obtain the working pressure of the oil film in the axial diameter clearance of the gear shaft through the hydraulic pressure and meshing force generated by the gear meshing during the operation of the gear pump;

[0039] A verification module, used for obtaining the working pressure of the gear shaft bearing surface according to the working pressure borne by the oil film in the shaft diameter clearance of the gear shaft;

[0040] The third calculation module is used to calculate the gear bearing load coefficient according to the minimum shaft diameter corresponding to the gear shaft under the condition of the output power load of the gear pump, the width of the sliding bearing, the circumferential speed of the gear shaft shaft diameter position, the working pressure of the gear shaft bearing surface and the dynamic viscosity of the gear pump working medium;

[0041] The fourth calculation module is used to obtain the fuel pump hole-shaft matching clearance value according to the gear bearing load coefficient.

[0042] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art: according to the design point parameters required for designing the fuel pump, the relevant values ​​of the gear shaft and the sliding bearing are calculated, and then the working pressure between the gear shaft and the sliding bearing is obtained through the relevant values ​​of the gear shaft and the sliding bearing, thereby obtaining the hole-shaft clearance value. Compared with the prior art, the engineering cycle can be shortened and the trial and error cost can be reduced. The required values ​​can be obtained through the method and system disclosed in the present application, and the design can be performed according to the obtained relevant values. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0045] Figure 1 A schematic flow chart of a method for matching a hole and a shaft of a ramjet fuel pump provided in an embodiment of the present application;

[0046] Figure 2 A schematic flow chart of a ramjet engine fuel pump hole-shaft matching system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0048] In order to improve the operating efficiency and stability of the engine fuel pump during the development process of miniaturization, heightening and lightweighting, and overcome the unfavorable factors that restrict the operating efficiency and stability of the gear pump, an embodiment of the present application provides a ramjet engine fuel pump hole-shaft matching method and system, wherein the engine fuel pump includes a gear pump and a sliding bearing.

[0049] See also Figure 1 , is a schematic diagram of a flow chart of a ramjet engine fuel pump hole-shaft matching method provided in an embodiment of the present application. As shown in the figure,

[0050] In step S100, the design point parameters of the fuel pump and the selected materials of the gear pump are obtained.

[0051] The fuel pump design point parameters are related to the fuel pump parameters to be designed. The fuel pump design point parameters are input into the system according to the designed fuel pump related parameters.

[0052] In the embodiment of the present application, the gear pump design point parameters include: design speed n, flow rate Q, and pressure difference ΔP before and after the pump. Among them, the speed n is the rotation speed of the gear pump, the flow rate Q is the flow rate of kerosene in the gear pump, and the pressure difference before and after the pump refers to the pressure difference before and after the rotation in the gear pump.

[0053] The material of the fuel pump gear pump determines the material yield point stress and allowable shear stress in the design parameters, as well as other material-related parameters.

[0054] When a fuel pump needs to be designed, the design parameters are input into the system according to the requirements of the fuel pump, and the algorithm in the system calculates the fuel pump hole-shaft clearance value based on the input parameter values.

[0055] In step S200, the output power, torque, the minimum shaft diameter, the sliding bearing width and the circumferential speed of the gear shaft at the shaft diameter position corresponding to the gear shaft under the output power load of the gear pump are calculated based on the design point parameters of the fuel pump and the yield point stress and allowable shear stress of the material selected for the gear pump.

[0056] Specifically, the gear pump design point parameters include: design speed n, flow rate Q, pressure difference ΔP before and after the pump; gear pump material yield point stress and allowable shear stress [τ].

[0057] The corresponding value is calculated according to the following formula:

[0058] Gear pump output power P c =Q·ΔP;

[0059] Torque

[0060] The minimum shaft diameter of the gear shaft under the condition of bearing the output power load of the gear pump

[0061] Peripheral speed of gear shaft at axial diameter position: n is the rotation speed;

[0062] The width B of the sliding bearing is calculated based on the width-to-diameter ratio B / d=1.1.

[0063] During high-speed rotation of the gear pump, the best supporting oil film can be formed in the gap between the gear shaft diameter and the inner diameter of the sliding bearing hole. The output power and torque of the gear pump can be used to calculate the minimum shaft diameter value that the gear pump can withstand under the output power load. Based on the empirical ratio of the bearing width to the minimum shaft diameter value B / d = 1.1, the value of the sliding bearing width B can be calculated.

[0064] The calculated minimum shaft diameter and bearing width values ​​are used in the following steps to calculate the working pressure on the gear shaft bearing surface.

[0065] In step S300, the working pressure borne by the oil film in the axial diameter clearance of the gear shaft is obtained through the hydraulic pressure and meshing force generated by the gear meshing during the operation of the gear pump.

[0066] The oil film in the gear shaft diameter clearance is subjected to the hydraulic pressure and meshing force generated by the gear meshing. Therefore, the working pressure borne by the oil film in the gear shaft diameter clearance can be expressed as the sum of the hydraulic pressure and the meshing force.

[0067] Therefore, the hydraulic pressure F generated by the gear meshing during the operation of the gear pump i =aΔPbd d , a calculation coefficient, b gear width, d d The hydraulic pressure is directly proportional to the gear width, the tooth top circle diameter and the pressure before and after the pump.

[0068] Meshing force:

[0069] Working pressure F borne by the oil film in the gear shaft diameter clearance Σ =F i +F n .

[0070] In step S400, the working pressure on the gear shaft axial diameter surface is obtained according to the working pressure borne by the oil film in the axial diameter gap of the gear shaft;

[0071] The working pressure of the oil film in the gear shaft axial diameter clearance calculated in step S300 can be converted to obtain the working pressure when it is applied to the gear shaft axial diameter surface, and the formula is as follows:

[0072] Gear shaft bearing surface working pressure F ∑The total meshing force, d is the minimum shaft diameter of the gear shaft, and b is the gear width.

[0073] The above formula is used to verify whether the calculated values ​​of the minimum journal value d of the gear shaft and the gear width b are reasonable. If P is greater than the critical value, d and b must be revalued, because when the P value is greater than the critical value, the oil film will rupture, making it impossible to carry the high-speed operation of the shaft diameter.

[0074] Therefore, the design process in step 100 may be readjusted to recalculate the P value until the P value meets the requirement.

[0075] In step 500, the gear bearing load coefficient is calculated based on the minimum shaft diameter corresponding to the gear shaft under the condition of the gear pump output power load, the sliding bearing width, the circumferential speed of the gear shaft shaft diameter position, the gear shaft bearing surface working pressure and the gear pump working medium dynamic viscosity.

[0076] Relative clearance value of hole-shaft fit ψ;

[0077] Gear bearing load factor Dynamic viscosity η of the working medium of the gear pump.

[0078] The dynamic viscosity value of the gear pump working medium is obtained by referring to relevant materials.

[0079] In step 600, the fuel pump hole-shaft matching clearance value is obtained according to the gear bearing load coefficient.

[0080] The gear bearing load coefficient and the aspect ratio value B / b calculated in step 500 can be used to obtain the eccentricity of the gear by referring to the design manual.

[0081] By formula Get the fuel pump hole-shaft clearance value.

[0082] From the above process, it can be seen that when calculating the hole-shaft clearance value, it is necessary to obtain the output power and torque of the gear pump based on the gear pump design point parameter value, and obtain the minimum shaft diameter value of the gear pump based on the torque value. At the same time, the working pressure of the oil film between the gear bearing and the sliding bearing is calculated. Therefore, based on the working pressure value of the oil film, it is further verified that the gear width and the minimum shaft diameter value are reasonable enough.

[0083] If the gear width and minimum shaft diameter are the same, the hole-shaft clearance value can be further calculated based on the total working pressure borne by the oil film.

[0084] The matching clearance value between the inner hole of the sliding bearing and the gear shaft diameter can realize the matching relationship between the gear shaft and the sliding bearing. This clearance value directly affects the operating reliability and efficiency of the kerosene gear pump.

[0085] If the clearance value is too small, the gear shaft diameter and the inner hole of the sliding bearing will fit too tightly, which will increase mechanical friction loss, aggravate the wear of the inner hole of the sliding bearing, destroy the operating stability and shorten the operating life; if the clearance value is too large, it will increase the vibration of the sliding bearing during rotation and shorten the operating life.

[0086] As can be seen from the above description, in the technical solution disclosed in the present application, the minimum shaft diameter and gear width of the gear shaft design can be determined by combining the design point parameters of the fuel pump, the output power and torque of the gear pump during actual operation, and the working pressure of the hole shaft oil film between the shaft diameter of the gear shaft of the gear pump and the sliding bearing, and then the hole shaft clearance value can be obtained. During the entire calculation process, combined with the problems that may be encountered in the actual operation of the gear shaft and the sliding bearing, the value can be adjusted through the calculation process, which can reduce the engineering cycle and reduce the trial and error cost.

[0087] The present application also provides an embodiment, a ramjet engine fuel pump hole-shaft matching system, comprising:

[0088] The acquisition module is used to obtain the design point parameters of the fuel pump and the selected materials of the gear pump.

[0089] The first calculation module is used to calculate the output power, torque, the minimum shaft diameter, the sliding bearing width and the circumferential speed of the gear shaft at the shaft diameter position corresponding to the gear shaft under the condition of the output power load of the gear pump according to the design point parameters of the fuel pump and the yield point stress and allowable shear stress of the material selected for the gear pump.

[0090] The second calculation module is used to obtain the working pressure borne by the oil film in the axial diameter clearance of the gear shaft through the hydraulic pressure and meshing force generated by the gear meshing during the operation of the gear pump.

[0091] The verification module is used to obtain the working pressure on the gear shaft bearing surface according to the working pressure borne by the oil film in the shaft diameter clearance of the gear shaft.

[0092] The third calculation module is used to calculate the gear bearing load coefficient based on the minimum shaft diameter corresponding to the gear shaft under the condition of the output power load of the gear pump, the width of the sliding bearing, the circumferential speed of the gear shaft shaft diameter position, the working pressure on the gear shaft bearing surface and the dynamic viscosity of the gear pump working medium.

[0093] The fourth calculation module is used to obtain the fuel pump hole-shaft matching clearance value according to the gear bearing load coefficient.

[0094] The ramjet fuel pump hole-shaft matching system disclosed in the present application obtains the module or the relevant design point parameters of the fuel pump, and then calculates and verifies the relevant data through the first calculation module, the verification module, the second calculation module, the third calculation module and the fourth calculation module, and finally obtains the hole-shaft matching clearance value that can reduce the friction loss and mechanical loss caused by the matching between the parts and improve the overall efficiency without the gear pump. The engineering cycle of the fuel pump design is shortened and the sunk cost is reduced.

[0095] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0096] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for matching the hole and shaft of a ramjet fuel pump, wherein the ramjet fuel pump comprises a gear pump, a gear shaft, and a sliding bearing, characterized in that: include: Obtain the design point parameters of the fuel pump and the selected materials of the gear pump; Calculate the output power, torque, the minimum shaft diameter, the width of the sliding bearing and the circumferential speed of the gear shaft at the shaft diameter position corresponding to the gear shaft under the output power load of the gear pump according to the design point parameters of the fuel pump and the yield point stress and the allowable shear stress of the material selected for the gear pump; The working pressure of the oil film in the gear shaft diameter clearance is obtained through the hydraulic pressure and meshing force generated by the gear meshing during the operation of the gear pump; According to the working pressure borne by the oil film in the axial diameter gap of the gear shaft, the working pressure on the gear shaft bearing surface is obtained; The gear bearing load coefficient is calculated based on the minimum shaft diameter of the gear shaft under the condition of the output power load of the gear pump, the width of the sliding bearing, the circumferential speed of the gear shaft shaft diameter position, the working pressure of the gear shaft bearing surface and the dynamic viscosity of the working medium of the gear pump; According to the gear bearing load coefficient, the fuel pump hole-shaft clearance value is obtained. The calculation of the output power, torque, the minimum shaft diameter, the width of the sliding bearing and the circumferential speed of the gear shaft at the shaft diameter position corresponding to the gear shaft under the condition of the output power load of the gear pump according to the design point parameters of the fuel pump and the yield point stress and the allowable shear stress of the material selected for the gear pump includes: The design point parameters of the gear pump include: the gear pump's rotation speed n, flow rate Q, and the pressure difference ΔP before and after the pump; Gear pump material yield point stress and allowable shear stress [τ]; Gear pump output power P c =Q·ΔP; Torque The minimum shaft diameter of the gear shaft under the condition of bearing the output power load of the gear pump Peripheral speed of gear shaft at axial diameter position: The width B of the sliding bearing is calculated based on the width-to-diameter ratio B / d=1.

1. The working pressure of the oil film in the gear shaft diameter clearance is obtained through the hydraulic pressure and meshing force generated by the gear meshing during the operation of the gear pump, including: The hydraulic pressure F generated by the gear meshing during the operation of the gear pump i =aΔPbd d , a calculation coefficient, b gear width, d d Tip diameter; Meshing force: The working pressure of the oil film in the gear shaft diameter clearance is FΣ=F i +F n ; According to the working pressure of the oil film in the gear shaft diameter clearance, the working pressure on the gear shaft bearing surface is obtained, including: Gear shaft bearing surface working pressure The gear bearing load coefficient is calculated based on the minimum shaft diameter of the gear shaft under the condition of the output power load of the gear pump, the width of the sliding bearing, the circumferential speed of the gear shaft shaft diameter position, the working pressure of the gear shaft bearing surface and the dynamic viscosity of the gear pump working medium, including: Relative clearance value of hole-shaft fit ψ; Gear bearing load factor Dynamic viscosity η of the working medium of the gear pump; According to the gear bearing load coefficient, the fuel pump hole shaft matching clearance value is obtained, including: According to the gear bearing load coefficient Cp and the aspect ratio B / d value, the eccentricity χ is obtained; By formula Get the fuel pump hole-shaft clearance value.

2. The ramjet engine fuel pump hole-shaft matching method according to claim 1, characterized in that: The working pressure P on the gear shaft bearing surface is used to verify whether the values ​​of the gear shaft minimum shaft diameter d and the gear width b are reasonable; If the working pressure P on the gear shaft bearing surface is greater than a critical value, the minimum shaft diameter d of the gear shaft and the gear width b are re-determined.

3. A ramjet fuel pump hole-shaft matching system, implemented by the method according to claim 1 or claim 2, characterized in that: include: The acquisition module is used to obtain the design point parameters of the fuel pump and the selected materials of the gear pump; The first calculation module is used to calculate the output power, torque, the minimum shaft diameter, the width of the sliding bearing and the circumferential speed of the gear shaft shaft diameter position corresponding to the gear shaft under the condition of the output power load of the gear pump according to the design point parameters of the fuel pump and the yield point stress and the allowable shear stress of the material selected for the gear pump; The second calculation module is used to obtain the working pressure of the oil film in the axial diameter clearance of the gear shaft through the hydraulic pressure and meshing force generated by the gear meshing during the operation of the gear pump; A verification module, used for obtaining the working pressure of the gear shaft bearing surface according to the working pressure borne by the oil film in the shaft diameter clearance of the gear shaft; The third calculation module is used to calculate the gear bearing load coefficient according to the minimum shaft diameter corresponding to the gear shaft under the condition of the output power load of the gear pump, the width of the sliding bearing, the circumferential speed of the gear shaft shaft diameter position, the working pressure of the gear shaft bearing surface and the dynamic viscosity of the gear pump working medium; The fourth calculation module is used to obtain the fuel pump hole-shaft matching clearance value according to the gear bearing load coefficient.

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