Engineering estimation method for high-speed train lift wing and wing-car cooperative aerodynamic characteristics

Abstract

This invention relates to the field of high-speed train aerodynamics and EMU equipment, specifically to an engineering estimation method for the aerodynamic characteristics of high-speed train lifting wings and wing-car cooperative systems. Taking high-speed trains equipped with multi-unit lifting wings as the object, based on finite fundamental theory, numerical simulation, and experimental testing, this invention addresses key technical parameters for the aerodynamic design selection and cooperative layout optimization of the lifting wings on high-speed trains. Through engineering experience and theoretical methods, it rapidly clarifies the airfoil lift coefficient and distribution characteristics, lift line characteristics, drag characteristics, and aerodynamic interference effects of wing-car cooperative operation of the lifting wing and wing-car system. This enables universal assessment and general engineering calculation of the aerodynamic characteristics of high-speed trains, providing strong reference and technical support for the development and application of lifting wing systems for 400+ km / h wheel-rail trains and high-speed maglev trains.

Description

Technical Field

[0001] This invention relates to the field of high-speed train aerodynamics and EMU equipment, specifically to an engineering estimation method for the aerodynamic characteristics of high-speed train lifting wings and wing-car cooperative aerodynamic characteristics. Background Technology

[0002] As operating speeds increase, wheel wear on wheel-rail trains will intensify, inevitably shortening wheel refinishing cycles and service life. To reduce the total life-cycle cost of trains at higher speeds, a high-speed train concept with lifting wings has been proposed. This concept breaks through the traditional aerodynamic design philosophy of high-speed trains, combining the advantages of both high-speed trains and aircraft. The aim is to increase the aerodynamic lift of the train, thereby achieving overall energy conservation and emission reduction.

[0003] In the late 20th century, Tohoku University in Japan first proposed the design concept of an "aerodynamic levitation train." This concept utilizes ground effect wings placed near the ground to enhance lift and provide the train with lift. Preliminary design studies were conducted on the airfoils used in aerodynamic levitation trains, concluding that their transport efficiency would be higher than that of maglev trains and high-speed commercial airliners. An experimental aerodynamic levitation train model was built, and a conceptual design scheme incorporating lifting wings was proposed, featuring "airplane-like wings" on the roof and sides of the train. Several alternative airfoils were also identified. These studies demonstrate that designing lifting wings with excellent aerodynamic characteristics is crucial for the technology of lifting wing trains. To date, various design schemes have been proposed to achieve this goal, such as the Chinese utility model patent with authorization announcement number CN113602299B, entitled "A Telescopic Wing Device for Aerodynamic Regulation of High-Speed ​​Trains, High-Speed ​​Trains and Control Methods"; authorization announcement number CN210133111U, entitled "A Side Wing Lift Control Mechanism for High-Speed ​​Rail Transit Trains"; and authorization announcement numbers CN202175052U and CN202175053U, which disclose a high-speed train wing device. However, overall, these schemes have not been fully integrated with the actual development of high-speed trains, particularly in terms of the design scheme of the lifting wing structure, installation arrangement, control method, and practical application, which are essentially nonexistent. Therefore, in the current context of my country's large-scale development of high-speed intelligent and green railway equipment, developing and deploying a high-speed train lifting wing device that offers significant lift enhancement, low drag coefficient, low aerodynamic noise, small installation space, high applicability to existing high-speed trains, intelligent control, and effective handling of complex wind environments is one of the urgent problems to be solved in the current efforts to accelerate the operation of high-speed trains and implement energy conservation and emission reduction in the development of green railway equipment.

[0004] Lifting wings utilize air as the primary braking power source for high-speed trains during high-speed operation, regulating lift. Their braking stability and safety are directly affected by external wind conditions. When high-speed trains equipped with lifting wing devices operate, the aerodynamic effects become increasingly pronounced with increasing speed and crosswind intensity, leading to a sharp deterioration in aerodynamic performance. Both lateral aerodynamic force and lift increase non-linearly, and the resulting aerodynamic loads severely impact the train's track dynamics, potentially causing derailment, overturning, and fatalities. As an auxiliary lift enhancement device for high-speed trains, the optimal applicable speed range is 400 km / h and above. Higher speeds result in greater effective aerodynamic lift and more pronounced aerodynamic effects. Aerodynamic characteristics are typically assessed and calculated through wind tunnel or track testing, but these methods are costly and challenging, making multi-condition adaptability research for lifting wing applications difficult. Therefore, based on finite fundamental theories, numerical simulations, and experimental tests, this invention conducts a general assessment and calculation of the aerodynamic characteristics of high-speed train lifting wings and their cooperative layout optimization on high-speed trains. It proposes an engineering estimation method for the aerodynamic characteristics of high-speed train lifting wings and wing-vehicle cooperative aerodynamic characteristics, which is a necessary condition for the development and application of lifting wing devices. Summary of the Invention

[0005] To adapt to the aerodynamic characteristics of multi-unit lifting wings for high-speed trains and their cooperative aerodynamic control with the external environment, this invention proposes an engineering estimation method for the cooperative aerodynamic characteristics of high-speed train lifting wings and wing-car systems. This method aims to quickly and clearly define the airfoil lift coefficient and distribution characteristics, lift line characteristics, drag characteristics, and aerodynamic interference effects of the lifting wing and wing-car system through general experience and theoretical methods.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] An engineering estimation method for the aerodynamic characteristics of a high-speed train lifting wing and wing-body combination is presented. Taking a high-speed train equipped with a multi-unit lifting wing as the research object, this method, based on fundamental theory, numerical simulation, and experimental testing, conducts a general assessment and calculation of the aerodynamic characteristics of the lifting wing, focusing on key technical parameters for aerodynamic design selection and optimization of its cooperative layout on the high-speed train. The estimation of the aerodynamic characteristics of the high-speed train lifting wing mainly includes the lift coefficient of the airfoil and its lateral distribution characteristics along the train, lift line characteristics, and drag characteristics. The estimation of the aerodynamic characteristics of the wing-body combination mainly includes the aerodynamic interference effect of the high-speed train body on the lifting wing and the aerodynamic interference effect of the lifting wing on the inherent flow field and roof equipment and facility layout of the high-speed train.

[0008] The multi-unit lifting wing is a lift control body adapted to high-speed trains with speeds of 400 km / h and above for aerodynamic coordinated utilization. The overall structure of the lifting wing is symmetrically and smoothly transitioned to the left and right sides along the central wing section. It is movably connected to the lifting wing control mechanism on the roof of the high-speed train by installing a lifting frame, which can adapt to and meet the selection of multiple angles of attack of the lifting wing.

[0009] The specific engineering estimation method for the aerodynamic characteristics of the lifting wing and wing-vehicle cooperative aerodynamic characteristics of high-speed trains includes the following steps:

[0010] 1) Engineering estimation of lift coefficient and lateral distribution characteristics of high-speed train lifting wing profile:

[0011] When the lifting wing of the high-speed train is a straight wing with a large aspect ratio, the lift coefficient of the airfoil is calculated using the lift line theory; when the lifting wing of the high-speed train is a lift control wing with a small aspect ratio or a lift control wing with a sweep angle, the lift coefficient of the airfoil is calculated using the lift surface theory.

[0012] In engineering estimation, the lift coefficient of the high-speed train's lifting fin is equal to the sum of the basic lift coefficient and the additional lift coefficient. The general calculation formula is as follows:

[0013] C L ′(z)=C L ′ b (z)+C L ′ a (z), where: C L ′(z) is the lift coefficient of the lifting wing of the high-speed train; C L ′ b (z) is the basic lift coefficient of the high-speed train's lifting wing; C L ′ a (z) is the additional lift coefficient of the lifting wing of the high-speed train;

[0014] 11) Determination of the basic lift coefficient of the lifting wing: When the lifting wing of the high-speed train is in an environment without crosswinds or when the aerodynamic torsion of the lifting wing is caused by the track environment, the basic lift coefficient of the high-speed train is calculated according to the following formula:

[0015]

[0016] In the formula: C L ′ b (z) represents the basic lift coefficient of the high-speed train; The slope of the lift line corresponding to the infinitely long lifting wing; Let α be the vertical velocity potential function; 0a The absolute zero angle of attack is the geometric twist caused by changes in the operating conditions and the motion state of the train.

[0017] 12) Determination of the additional lift coefficient of the lifting wing: The additional lift coefficient of the high-speed train's lifting wing is estimated through engineering experience by referring to the parameter characteristics of an elliptical lifting wing under the same conditions. The calculation formula is as follows:

[0018]

[0019] In the formula: b0 is the root chord length of the reference elliptical lifting wing; z is the vertical vector value; k is the total lateral length of the lifting wing;

[0020] 2) Determination of the lifting line characteristics of the high-speed train's lifting wing: The lifting line of the high-speed train's lifting wing is characterized by the zero-lift angle of attack, the slope of the lifting line, and the maximum lift coefficient. The calculation formula is as follows:

[0021]

[0022] In the formula: α is the angle of attack; α0 is the zero-lift angle of attack, calculated as follows: Where α 0∞ η is the angle of attack corresponding to an infinitely long lifting wing, and η is the root-to-tip ratio of the lifting wing. The reference velocity potential function; The slope of the lift line of the lifting wing is calculated using the following formula:

[0023]

[0024] In the formula: λ is the aspect ratio; χ 1 / 2 A sweep angle of 0.5 chord length;

[0025] The maximum lift coefficient of the high-speed train's lifting wing is C, which is the maximum lift coefficient of the intermediate airfoil section located on the longitudinal center plane of the lifting wing. Lmax0 The maximum lift coefficient C of the airfoil at both ends of the high-speed train's lifting wing Lmax1 The formula for calculating the project estimate is: C Lmax =k s (C Lmax0 +C Lmax1 ) / 2; where the coefficient k is used to estimate the lift wings that are laterally symmetrically arranged on the roof of the high-speed train. s The range is 0.75 to 0.85; for the laterally symmetrically arranged lifting wings with a sweep angle on the roof of high-speed trains, the estimation coefficient k is taken. s The range is 0.86 to 0.95;

[0026] 3) Determination of the aerodynamic drag characteristics of the lifting wing of the high-speed train:

[0027] The aerodynamic drag coefficient C of the high-speed train's lifting wing D Engineering estimates equal zero-liter aerodynamic drag coefficient C D0and the drag coefficient C DL The sum, expressed as: C D =C D0 +C DL The zero-lift aerodynamic drag coefficient C is mentioned above. D0 The engineering estimation uses parameters at the average chord length of the lifting wing of the high-speed train for calculation, and the calculation formula is as follows:

[0028] C D0 =(2C F ) bav (1+0.1t+0.4t 2 ),

[0029] In the formula, C F y is the frictional drag coefficient for winglets with equal chord lengths; t is the relative thickness of the winglet, representing the maximum dimensionless height between the upper and lower chords of the winglet, i.e., t = max[y]. u (x)-y d [x], where y u (x) represents the relative coordinates of the upper arc of the lifting wing, y d (x) represents the relative coordinates of the lower chord; k a k is an empirical constant, estimated to range from 0.15 to 0.2. b This is an empirical constant, and its estimated value range is 0.41 to 0.5.

[0030] The lift-induced drag coefficient C DL In engineering estimation, it equals the induced aerodynamic drag coefficient plus the viscous pressure drag coefficient C. Dn The sum of C Di The calculation formula is: C DL =C Di +C Dn ;

[0031] in, In the formula, (0.05λ-δ) / πλ is the correction term, which is usually determined by wind tunnel test or actual vehicle line test data of a high-speed train equipped with a lifting wing at a scale of not less than 1:8. δ is the correction coefficient of the lifting wing of the high-speed train, which is estimated to be 0.05 to 0.15 according to the degree of deviation of the lifting wing from the optimal planar shape.

[0032] 4) Quantitative assessment of the interference effect of high-speed train lifting wing:

[0033] 41) Calculation of the aerodynamic interference coefficient of the series lifting wings on the roof of the high-speed train: The aerodynamic interference coefficient of the series lifting wings on the roof of the high-speed train is obtained by considering the longitudinal aerodynamic drag F of the series wings. D To characterize this, the calculation formula is as follows:

[0034]

[0035] In the formula, C d0 The aerodynamic drag coefficient of a single lifting wing on the vehicle roof is given; the engineering estimation uses a single-set deployment case. (C) d1 (i) represents the direct interference coefficient of the i-th lifting wing from front to back in the windward direction; A d ρ is the longitudinal projected area of ​​the lifting wing device; n is the number of sets of tandem lifting wings installed; ρ is the air density of the operating environment; v is the operating speed of the high-speed train equipped with lifting wings.

[0036] 42) Calculation of the interference effect between the lifting wings and the train on a high-speed train equipped with lifting wings:

[0037] The interference effect of the lifting wing on the high-speed train equipped with the lifting wing and the train is estimated by engineering through the overall aerodynamic cooperative lift coefficient of the two, and the calculation formula is as follows:

[0038] C Lt =(L ws +L sw ) / (0.5ρv 2 S0), where: L ws The lift generated by the lifting wing is designed to be compatible with high-speed trains; L sw The lift generated by the high-speed train is taken into account for the lifting wing; S0 is the projected area of ​​the lifting wing in the vertical direction of the high-speed train;

[0039] Preferably, in step 11), the flat-plate helicopter wing adapted for high-speed trains corresponds to... The absolute zero lift angle of attack α of the high-speed train is caused by the geometric twist due to changes in track conditions and the motion state of the train body. 0a The value is equal to the angle between the zero-lift line and the zero-lift line of the mid-section airfoil, calculated by the following formula:

[0040]

[0041] In the formula: F L Let b(z) be the lift force of the lifting wing; b(z) be the vertical chord length function of the lifting wing; and S be the cross-sectional area of ​​the longitudinal center plane of the train where the lifting wing is located.

[0042] Preferably, the effective installation space of the multi-unit lifting wing in the transverse section is the area above the roof between the railway construction clearance and the vehicle clearance. The width (K) of this area is less than or equal to the transverse dimensions of the train, and the height (H) of this area is less than the pantograph lifting height of the high-speed train minus a safety height margin of 400mm. The geometric design dimensions of the lifting wing in the transverse section meet the spatial scale requirements of both the railway construction clearance and the vehicle clearance. The transverse width (k) of the lifting wing is less than or equal to the transverse dimensions of the train, and is 1600–2000mm. The chord length (c) of the lifting wing is equal to 0.5–1 times the transverse width (k), and is 800–2000mm. The maximum thickness (tmax) of the central airfoil of the lifting wing is 250–400mm, and the vertical distance (cx) from the position of the maximum thickness (tmax) to the leading edge is 200–400mm. The leading edge radius (r) of the lifting wing is 20–50mm. The trailing edge angle (R2) of the lifting wing is 5–15 degrees.

[0043] Preferably, the mounting and lifting frame is connected at the center of the longitudinal chord of the lower chord surface of the lifting wing. When the lifting wing is working, under the support and lifting control of the mounting and lifting frame, the normal working height (h) is 300-800mm and the normal working angle of attack (R) is 0-30 degrees.

[0044] The beneficial effects of this invention are as follows: Based on finite fundamental theories, numerical simulations, and experimental tests, this invention addresses the key technical parameters of aerodynamic design selection and collaborative layout optimization of lifting wings on high-speed trains. Through general experience and theoretical methods, it can quickly and clearly define the airfoil lift coefficient and distribution characteristics, lift line characteristics, drag characteristics, and aerodynamic interference effects of the lifting wing and wing-car system. This enables universal evaluation and general engineering calculation of the aerodynamic characteristics of high-speed trains, and can provide strong reference and technical support for the development and application of lifting wing systems for wheel-rail trains with speeds of 400+ km / h and high-speed maglev trains. Attached Figure Description

[0045] Figure 1 This is a flowchart of the engineering estimation method for the aerodynamic characteristics of a high-speed train lifting wing and wing-vehicle cooperative system according to the present invention.

[0046] Figure 2 The installation layout space size requirements of the high-speed train to which this invention is adapted under railway clearance constraints;

[0047] Figure 3 The present invention relates to three typical lifting wing structures and key technical parameters.

[0048] Figure 4 A three-dimensional structural diagram of a high-speed train lifting wing device adapted to the present invention (adapted to multiple angles of attack, multiple turning angles, and multiple heights);

[0049] Figure 5 This is a three-dimensional structural diagram of another high-speed train lifting wing device (wing and adjustment device) adapted to this invention. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings:

[0051] An engineering estimation method for the aerodynamic characteristics of a high-speed train lifting wing and wing-body combination is presented. Taking a high-speed train equipped with a multi-unit lifting wing as the research object, this method, based on fundamental theory, numerical simulation, and experimental testing, conducts a general assessment and calculation of the aerodynamic characteristics of the lifting wing, focusing on key technical parameters for aerodynamic design selection and optimization of its cooperative layout on the high-speed train. The estimation of the aerodynamic characteristics of the high-speed train lifting wing mainly includes the lift coefficient of the airfoil and its lateral distribution characteristics along the train, lift line characteristics, and drag characteristics. The estimation of the aerodynamic characteristics of the wing-body combination mainly includes the aerodynamic interference effect of the high-speed train body on the lifting wing and the aerodynamic interference effect of the lifting wing on the inherent flow field and roof equipment and facility layout of the high-speed train.

[0052] The multi-unit lifting wing is a lift control body adapted for aerodynamic synergy utilization by high-speed trains with speeds of 400 km / h and above. The overall structure of the lifting wing has a smooth and symmetrical transition to the left and right sides along the central wing section. It is movably connected to the lifting wing control mechanism on the roof of the high-speed train by a mounting lifting frame, which can adapt to the selection of multiple angles of attack of the lifting wing. The mounting lifting frame is connected at the center of the longitudinal chord of the lower chord surface of the lifting wing. When the lifting wing is working, under the support and lifting control of the mounting lifting frame, the normal working height (h) is 300-800 mm, and the normal working angle of attack (R) is 0-30 degrees.

[0053] like Figure 1 As shown, the engineering estimation method for the aerodynamic characteristics of the high-speed train lifting wing and wing-vehicle cooperative system specifically includes the following steps:

[0054] 1) Engineering estimation of lift coefficient and lateral distribution characteristics of high-speed train lifting wing profile:

[0055] When the lifting wing of the high-speed train is a straight wing with a large aspect ratio, the lift coefficient of the airfoil is calculated using the lift line theory; when the lifting wing of the high-speed train is a lift control wing with a small aspect ratio or a lift control wing with a sweep angle, the lift coefficient of the airfoil is calculated using the lift surface theory.

[0056] In engineering estimation, the lift coefficient of the high-speed train's lifting fin is equal to the sum of the basic lift coefficient and the additional lift coefficient. The general calculation formula is as follows:

[0057] C L′(z)=C L ′ b (z)+C L ′ a (z), where: C L ′(z) is the lift coefficient of the lifting wing of the high-speed train; C L ′ b (z) is the basic lift coefficient of the high-speed train's lifting wing; C L ′ a (z) is the additional lift coefficient of the lifting wing of the high-speed train;

[0058] 11) Determination of the basic lift coefficient of the lifting wing: When the lifting wing of the high-speed train is in an environment without crosswinds or when the aerodynamic torsion of the lifting wing is caused by the track environment, the basic lift coefficient of the high-speed train is calculated according to the following formula:

[0059]

[0060] In the formula: C L ′ b (z) represents the basic lift coefficient of the high-speed train; The slope of the lift line corresponding to the infinitely long lifting wing; Let α be the vertical velocity potential function; 0a The absolute zero angle of attack is the geometric twist caused by changes in the operating conditions and the motion state of the train.

[0061] 12) Determination of the additional lift coefficient of the lifting wing: The additional lift coefficient of the high-speed train's lifting wing is estimated through engineering experience by referring to the parameter characteristics of an elliptical lifting wing under the same conditions. The calculation formula is as follows:

[0062]

[0063] In the formula: b0 is the root chord length of the reference elliptical lifting wing; z is the vertical vector value; k is the total lateral length of the lifting wing;

[0064] 2) Determination of the lifting line characteristics of the high-speed train's lifting wing: The lifting line of the high-speed train's lifting wing is characterized by the zero-lift angle of attack, the slope of the lifting line, and the maximum lift coefficient. The calculation formula is as follows:

[0065]

[0066] In the formula: α is the angle of attack; α0 is the zero-lift angle of attack, calculated as follows: Where α 0∞ η is the angle of attack corresponding to an infinitely long lifting wing, and η is the root-to-tip ratio of the lifting wing. The reference velocity potential function; The slope of the lift line of the lifting wing is calculated using the following formula:

[0067]

[0068] In the formula: λ is the aspect ratio; χ 1 / 2 A sweep angle of 0.5 chord length;

[0069] The maximum lift coefficient of the high-speed train's lifting wing is C, which is the maximum lift coefficient of the intermediate airfoil section located on the longitudinal center plane of the lifting wing. Lmax0 The maximum lift coefficient C of the airfoil at both ends of the high-speed train's lifting wing Lmax1 The formula for calculating the project estimate is: C Lmax =k s (C Lmax0 +C Lmax1 ) / 2; where the coefficient k is used to estimate the lift wings that are laterally symmetrically arranged on the roof of the high-speed train. s The range is 0.75 to 0.85; for the laterally symmetrically arranged lifting wings with a sweep angle on the roof of high-speed trains, the estimation coefficient k is taken. s The range is 0.86 to 0.95;

[0070] 3) Determination of the aerodynamic drag characteristics of the lifting wing of the high-speed train:

[0071] The aerodynamic drag coefficient C of the high-speed train's lifting wing D Engineering estimates equal zero-liter aerodynamic drag coefficient C D0 and the drag coefficient C DL The sum, expressed as: C D =C D0 +C DL The zero-lift aerodynamic drag coefficient C is mentioned above. D0 The engineering estimation uses parameters at the average chord length of the lifting wing of the high-speed train for calculation, and the calculation formula is as follows:

[0072] C D0 =(2C F ) bav (1+0.1t+0.4t 2 ),

[0073] In the formula, C F y is the frictional drag coefficient for winglets with equal chord lengths; t is the relative thickness of the winglet, representing the maximum dimensionless height between the upper and lower chords of the winglet, i.e., t = max[y]. u (x)-y d [x], where y u (x) represents the relative coordinates of the upper arc of the lifting wing, y d (x) represents the relative coordinates of the lower chord; k a k is an empirical constant, estimated to range from 0.15 to 0.2. bThis is an empirical constant, and its estimated value range is 0.41 to 0.5.

[0074] The lift-induced drag coefficient C DL In engineering estimation, it equals the induced aerodynamic drag coefficient plus the viscous pressure drag coefficient C. Dn The sum of C Di The calculation formula is: C DL =C Di +C Dn ;

[0075] in, In the formula, (0.05λ-δ) / πλ is the correction term, which is usually determined by wind tunnel test or actual vehicle line test data of a high-speed train equipped with a lifting wing at a scale of not less than 1:8. δ is the correction coefficient of the lifting wing of the high-speed train, which is estimated to be 0.05 to 0.15 according to the degree of deviation of the lifting wing from the optimal planar shape.

[0076] 4) Quantitative assessment of the interference effect of high-speed train lifting wing:

[0077] 41) Calculation of the aerodynamic interference coefficient of the series lifting wings on the roof of the high-speed train: The aerodynamic interference coefficient of the series lifting wings on the roof of the high-speed train is obtained by considering the longitudinal aerodynamic drag F of the series wings. D To characterize this, the calculation formula is as follows:

[0078]

[0079] In the formula, C d0 The aerodynamic drag coefficient of a single lifting wing on the vehicle roof is given; the engineering estimation uses a single-set deployment case. (C) d1 (i) represents the direct interference coefficient of the i-th lifting wing from front to back in the windward direction; A d ρ is the longitudinal projected area of ​​the lifting wing device; n is the number of sets of tandem lifting wings installed; ρ is the air density of the operating environment; v is the operating speed of the high-speed train equipped with lifting wings.

[0080] 42) Calculation of the interference effect between the lifting wings and the train on a high-speed train equipped with lifting wings:

[0081] The interference effect of the lifting wing on the high-speed train equipped with the lifting wing and the train is estimated by engineering through the overall aerodynamic cooperative lift coefficient of the two, and the calculation formula is as follows:

[0082] C Lt =(L ws +L sw ) / (0.5ρv 2 S0), where: L ws The lift generated by the lifting wing is designed to be compatible with high-speed trains; L swThe lift generated by the high-speed train is taken into account for the lifting wing; S0 is the projected area of ​​the lifting wing in the vertical direction of the high-speed train;

[0083] Preferably, in step 11), the flat-plate helicopter wing adapted for high-speed trains corresponds to... The absolute zero lift angle of attack α of the high-speed train is caused by the geometric twist due to changes in track conditions and the motion state of the train body. 0a The value is equal to the angle between the zero-lift line and the zero-lift line of the mid-section airfoil, calculated by the following formula:

[0084]

[0085] In the formula: F L Let b(z) be the lift force of the lifting wing; b(z) be the vertical chord length function of the lifting wing; and S be the cross-sectional area of ​​the longitudinal center plane of the train where the lifting wing is located.

[0086] refer to Figure 2 The effective installation space of the multi-unit lifting wing in the transverse section is the area above the roof between the railway construction clearance and the vehicle clearance. The width (K) of the area is less than or equal to the transverse dimensions of the train, and the height (H) of the area is less than the pantograph lifting height of the high-speed train minus a safety height margin of 400mm. The geometric design dimensions of the lifting wing in the transverse section meet the spatial scale requirements of the railway construction clearance and the vehicle clearance. The transverse width (k) of the lifting wing is less than or equal to the transverse dimensions of the train, and is 1600-2000mm. The chord length (c) of the lifting wing is equal to 0.5-1 times the transverse width (k), and is 800-2000mm. The maximum thickness (tmax) of the central airfoil of the lifting wing is 250-400mm, and the vertical distance (cx) from the position of the maximum thickness (tmax) to the leading edge is 200-400mm. The leading edge radius (r) of the lifting wing is 20-50mm. The trailing edge angle (R2) of the lifting wing is 5-15 degrees.

[0087] Figure 3The aerodynamic lift control body, supported by a lifting frame and mounted on the roof of a high-speed train, is applicable to the method described in this invention. It serves as a typical reference scheme for the development and application of lift wings for high-speed trains traveling at speeds of 400 km / h and for estimating their aerodynamic characteristics. The central airfoil of the lift wing has a plano-convex geometry with a convex upper section and a flat lower section, consisting of a lower chord, a leading edge, an upper arc, and a trailing edge connected sequentially. The lower chord is a straight line, and the upper arc is a polyspline. The overall structure of the lift wing smoothly transitions symmetrically to the left and right sides along the central airfoil section. The lower end of the lifting frame is connected to the lift wing control mechanism on the roof of the high-speed train, while the upper end is hinged and rotatably connected to the bottom of the lower arc surface of the lift wing in the longitudinal plane, accommodating the selection of multiple angles of attack for the lift wing. The effective installation space of the lifting wing in the transverse section is the area above the roof between the railway construction clearance and the vehicle clearance. The width K of this area is less than or equal to the transverse dimensions of the train, and the height H of this area is less than the pantograph lifting height of the high-speed train minus a safety height margin of 400mm. The geometric design dimensions of the lifting wing in the transverse section meet the spatial scale requirements of both the railway construction clearance and the vehicle clearance. The transverse width k of the lifting wing is less than or equal to the transverse dimensions of the train, and is 1600–2000mm. The chord length c of the lifting wing is equal to 0.5–1 times the transverse width k, and is 800–2000mm. The maximum thickness tmax of the central airfoil of the lifting wing is 250–400mm, and the vertical distance cx from the position of the maximum thickness tmax to the leading edge is 200–400mm. The leading edge radius r of the lifting wing is 20–50mm. The trailing edge angle R2 of the lifting wing is 5–15 degrees. The mounting frame is connected to the center of the longitudinal chord of the lower chord surface of the lifting wing. During operation, under the support and lifting control of the mounting frame, the normal operating height h of the lifting wing is 300–800 mm, and the normal operating angle of attack R is 0–30 degrees. Preferably, the normal operating height h of the lifting wing is 400 mm, and the normal operating angle of attack R1 is 20 degrees.

[0088] refer to Figure 3The illustration shows the first embodiment of the lifting wing: the lifting wing is a zero-angle plano-convex type lifting wing, where the symmetrical airfoils on both sides of the zero-angle plano-convex type lifting wing have the same geometric shape as the central airfoil. The chord length c of the zero-angle plano-convex type lifting wing is 1200mm, the lateral width k is 1800mm, the leading edge radius r is 25mm, the trailing edge angle R2 is 12 degrees, and the vertical distance cx from the leading edge tip is 250mm, corresponding to a maximum thickness tmax of 300mm. The second embodiment of the lifting wing: the lifting wing is a plano-convex type lifting wing with deflection, where the arc on the airfoil smoothly and symmetrically decreases from the center to both sides, and the vertical deflection angle R3 from the point corresponding to the maximum thickness of the central airfoil to the point corresponding to the maximum thickness of the outermost airfoil is 5-10 degrees. The chord length c of the angled plano-convex lifting wing is 1200mm, the lateral width k is 1800mm, the leading edge radius r is 25mm, the trailing edge angle R2 is 12 degrees, the vertical distance cx from the leading edge tip is 250mm, the corresponding maximum thickness tmax is 300mm, and the vertical deflection angle R3 is 12 degrees. A third embodiment of the lifting wing: The lifting wing is a swept-angle plano-convex lifting wing. On the airfoil of the swept-angle plano-convex lifting wing, the arc smoothly and symmetrically decreases from the middle to both sides. The vertical deflection angle R3 from the point corresponding to the maximum thickness of the central airfoil section to the point corresponding to the maximum thickness of the outermost airfoil section is 5–10 degrees. In the horizontal projection plane, the leading edge is symmetrically provided with a forward sweep angle Rq ranging from 75–90 degrees to both sides, and the trailing edge is symmetrically provided with a backward sweep angle Rh ranging from 45–90 degrees to both sides. The sweep-angle plano-convex lifting wing has a chord length c of 1200mm, a lateral width k of 1800mm, a leading edge radius r of 25mm, a trailing edge angle R2 of 12 degrees, a vertical distance cx from the leading edge end of 250mm, a corresponding maximum thickness tmax of 300mm, a vertical deflection angle R3 of 12 degrees, a forward sweep angle Rq of 80 degrees, and a backward sweep angle Rh of 80 degrees.

[0089] Figure 4A high-speed train lifting wing device to which the method described in this invention is applicable mainly includes a lifting wing, a lifting wing mounting base, and a control unit. Its features include: a bidirectional double-acting telescopic hydraulic drive device, a linkage assembly, a double-acting hydraulic lifting device, and a rotary drive assembly. The lifting wing comprises multiple stages of symmetrically arranged and nested together, which are sequentially connected and fixed to the plunger shaft of the double-acting hydraulic lifting device via the lifting wing mounting base. Under the coordinated drive of the bidirectional double-acting telescopic hydraulic drive device and the linkage assembly, the multiple stages of lifting wings achieve synchronous left-right lateral telescopic movement. The double-acting hydraulic lifting device drives the lifting wing to move up and down via the plunger shaft, while simultaneously achieving rotation and self-locking of the lifting wing device under the drive control of the rotary drive assembly. The longitudinal cross-sectional profile of the multi-stage lifting wing is a streamlined, closed structure formed by a bottom plate, a front side plate, and a tail side plate, with a parallel bottom and a convex top. The multi-stage lifting wing includes a left first-stage lifting wing, a left second-stage lifting wing, a left third-stage lifting wing, a right first-stage lifting wing, a right second-stage lifting wing, and a right third-stage lifting wing, which are symmetrically arranged and nested in stages. When the multi-stage lifting wing is deployed, the tail length of each stage of the lifting wing gradually shortens from the middle to both sides.

[0090] Figure 5 Another high-speed train lifting wing device applicable to the method described in this invention includes a telescopic wing, a height and pitch adjustment mechanism for adjusting the height and pitch angle of the telescopic wing in the vertical direction to provide lift or air resistance for the train, a rotating seat located at the bottom of the height and pitch adjustment mechanism for supporting the mechanism, and a rotating mechanism located below the rotating seat for driving the rotating seat to rotate, thereby rotating the telescopic wing to resist the lateral force of crosswinds. It can perform single or combined actions such as pitch, height, and rotation of the wing according to the actual operating environment and requirements of the train. By controlling and adjusting the attitude of the wing, the flow state of the airflow above and below the wing is changed, thereby changing the force exerted by the wing on the train, achieving the goal of regulating the operation and braking of the high-speed train.

[0091] It should be noted that the terms "front," "back," "up," and "down," etc., used in this document to indicate orientation or positional relationships are based on the positional relationships shown in the accompanying drawings. They are used solely for the convenience of describing the technical solution and for simplification, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the technical solution. The connection relationships mentioned can refer to direct or indirect connections. The technical terms and symbols in this document are given their corresponding markings and explanations in the order of their appearance, and are explained only once. The meanings, explanations, or descriptions of subsequent appearances of the same markings also apply.

[0092] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of this invention. Therefore, if these modifications and variations of this invention fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An engineering estimation method for the aerodynamic characteristics of a high-speed train lifting wing and wing-vehicle cooperative system, characterized in that: The method takes a high-speed train equipped with a multi-unit lifting wing as the research object. Based on basic theory, numerical simulation and experimental testing, it conducts a general assessment and calculation of the aerodynamic characteristics of the lifting wing of the high-speed train and the key technical parameters of the cooperative layout optimization on the high-speed train. The aerodynamic characteristics estimation of the high-speed train lifting wing includes the lift coefficient of the airfoil and its distribution characteristics along the train's lateral direction, lift line characteristics and drag characteristics. The estimation of the cooperative aerodynamic characteristics of the wing-car assembly includes the aerodynamic interference effect of the high-speed train body on the lifting wing and the aerodynamic interference effect of the lifting wing on the inherent flow field of the high-speed train and the layout of the equipment and facilities on the roof. The multi-unit lifting wing is a lifting control body adapted to high-speed trains with speeds of 400 km / h and above for aerodynamic coordinated utilization. The overall structure of the lifting wing is symmetrically and smoothly transitioned to the left and right sides along the central wing section. It is movably connected to the lifting wing control mechanism on the roof of the high-speed train by installing a lifting frame, which can adapt to meet the selection of multiple angles of attack, multiple turning angles and multiple lifting heights of the lifting wing. The specific engineering estimation method for the aerodynamic characteristics of the lifting wing and wing-vehicle cooperative aerodynamic characteristics of high-speed trains includes the following steps: 1) Engineering estimation of lift coefficient and lateral distribution characteristics of high-speed train lifting wing profile: When the lifting wing of the high-speed train is a straight wing with a large aspect ratio, the lift coefficient of the airfoil is calculated using the lift line theory; when the lifting wing of the high-speed train is a lift control wing with a small aspect ratio or a lift control wing with a sweep angle, the lift coefficient of the airfoil is calculated using the lift surface theory. In engineering estimation, the lift coefficient of the high-speed train's lifting wing is equal to the sum of the basic lift coefficient and the additional lift coefficient. The calculation formula is as follows: In the formula: The lift coefficient of the high-speed train's lifting wing; The basic lift coefficient of the high-speed train's lifting wing; Add a lift coefficient to the lifting wing of the high-speed train; 11) Determination of the basic lift coefficient of the lifting wing: When the lifting wing of the high-speed train is in an environment without crosswinds or when the aerodynamic torsion of the lifting wing is caused by the track environment, the basic lift coefficient of the high-speed train is calculated according to the following formula: ， In the formula: This refers to the basic lift coefficient of the high-speed train. The slope of the lift line corresponding to the infinitely long lifting wing; The vertical velocity potential function; The absolute zero angle of attack is the geometric twist caused by changes in the operating conditions and the motion state of the train. 12) Determination of the additional lift coefficient of the lifting wing: The additional lift coefficient of the high-speed train's lifting wing is estimated through engineering experience by referring to the parameter characteristics of an elliptical lifting wing under the same conditions. The calculation formula is as follows: ， In the formula: The chord length at the root of the reference elliptical lifting wing; The value is the vertical vector. This refers to the total lateral length of the lifting wing; 2) Determination of the lifting line characteristics of the high-speed train's lifting wing: The lifting line of the high-speed train's lifting wing is characterized by the zero-lift angle of attack, the slope of the lifting line, and the maximum lift coefficient. The calculation formula is as follows: ， In the formula: Angle of attack; For zero-lift angle of attack, the calculated value is... ,in For an infinitely long lifting wing, the angle of attack is... The root-to-tip ratio of the lifting wing; The reference velocity potential function; The slope of the lift line of the lifting wing is calculated using the following formula: ， In the formula: For aspect ratio; A sweep angle of 0.5 chord length; The maximum lift coefficient of the high-speed train's lifting wing is the maximum lift coefficient of the lifting wing's intermediate airfoil section located on the train's longitudinal center plane. The maximum lift coefficient of the airfoil at both ends of the high-speed train The formula for calculating project estimates is as follows: For the helical wings that are laterally symmetrically arranged on the roof of the high-speed train, the estimated coefficient is taken as... The range is 0.75~0.85; for the laterally symmetrically arranged lifting wings with sweep angles on the roof of high-speed trains, the estimation coefficient is taken as... The range is 0.86~0.95; 3) Determination of aerodynamic drag characteristics of high-speed train lifting wings: The aerodynamic drag coefficient of the high-speed train's lifting wing Engineering estimates equal zero-liter aerodynamic drag coefficient and lift-induced drag coefficient The sum is expressed as: The zero-lift aerodynamic drag coefficient is mentioned above. The engineering estimation uses parameters at the average chord length of the lifting wing of the high-speed train for calculation, and the calculation formula is as follows: ， In the formula, For wings with the same lift chord length, the coefficient of frictional drag is used. The relative thickness of the lifting wing represents the maximum dimensionless height between the upper chord and the lower chord of the lifting wing, i.e. ,in The relative coordinates of the arc on the lifting wing are: The relative coordinates of the lower chord; The lift-induced drag coefficient mentioned above In engineering estimation, it equals the induced aerodynamic drag coefficient plus the viscous pressure drag coefficient. The sum is calculated using the following formula: ; in, , In the formula For corrections, data from wind tunnel tests or actual track tests on a high-speed train equipped with lifting wings at a scale of no less than 1:8 are used to determine the corrective measures. The value is the correction factor for the lifting wing of the high-speed train. Based on the degree to which the lifting wing deviates from the optimal planar shape, the estimated value ranges from 0.05 to 0.

15. 4) Quantitative assessment of the interference effect of high-speed train lifting fins: 41) Calculation of the aerodynamic interference coefficient of the series lifting wings on the roof of the high-speed train: The aerodynamic interference coefficient of the series lifting wings on the roof of the high-speed train is calculated through the longitudinal aerodynamic drag of the series wings. To characterize this, the calculation formula is as follows: ， In the formula, The aerodynamic drag coefficient of a single lifting wing on the vehicle roof is used in the engineering estimation, which takes the case of one set of deployment. To face the wind direction from front to back The direct interference coefficient of the lifting wing; The longitudinal projected area of ​​the lifting wing; The number of sets of tandem lifting wings to be installed; The air density of the operating environment; To improve the operating speed of high-speed trains equipped with lifting wings; 42) Calculation of the interference effect between the lifting wing and the train on a high-speed train equipped with a lifting wing: The interference effect of the lifting wing on the high-speed train equipped with the lifting wing and the train is estimated by engineering through the overall aerodynamic cooperative lift coefficient of the two, and the calculation formula is as follows: In the formula: The lift generated by the lifting wing is designed to be compatible with high-speed trains; The lift generated by the lifting wing is adapted to the high-speed train. The area of ​​the lifting wing is the projected area of ​​the lifting wing in the vertical direction of the high-speed train.

2. The method of claim 1, wherein the method further comprises: determining the aerodynamic characteristics of the high-speed train lift wing and the wing car in coordination with the high-speed train lift wing and the wing car. In step 11), the corresponding flat-plate helicopter wing adapted for high-speed trains... The absolute zero-lift angle of attack of the high-speed train due to the geometric twisting caused by changes in track conditions and the motion state of the train body. The value is equal to the angle between the zero-lift line and the zero-lift line of the mid-section airfoil, calculated by the following formula: ； In the formula: The lift of the lifting wing; For the vertical chord length function of the lifting wing; This represents the cross-sectional area of ​​the longitudinal center surface of the train where the lifting wing is located.

3. The engineering estimation method for the aerodynamic characteristics of a high-speed train lifting wing and wing-vehicle cooperative system according to claim 1, characterized in that: The effective installation space of the multi-unit lifting wing in the transverse section is the area above the roof between the railway construction clearance and the vehicle clearance. The width of this area is less than or equal to the transverse dimensions of the train, and the height of this area is less than the pantograph lifting height of the high-speed train minus a safety height margin of 400 mm. The geometric design dimensions of the lifting wing in the transverse section meet the spatial dimensional requirements of both the railway construction clearance and the vehicle clearance. The transverse width of the lifting wing is less than or equal to the transverse dimensions of the train, and is 1600-2000 mm. The chord length of the lifting wing is equal to 0.5-1 times the transverse width, and is 800-2000 mm. The maximum thickness of the central airfoil of the lifting wing is 250-400 mm, and the vertical distance from the maximum thickness position to the leading edge is 200-400 mm. The leading edge radius of the lifting wing is 20-50 mm. The trailing edge angle of the lifting wing is 5-15 degrees.

4. The method of claim 1, wherein the method further comprises: determining the aerodynamic characteristics of the high-speed train lift wing and the wing car in coordination with the aerodynamic characteristics of the high-speed train lift wing and the wing car. The mounting frame is connected to the center of the longitudinal chord of the lower chord surface of the lifting wing. When the lifting wing is working, under the support and lifting control of the mounting frame, the normal working height is 300 ~ 800 mm, and the normal working angle of attack is 0 ~ 30 degrees.

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