JP5824295B2 - Railway vehicle with aerodynamic brake - Google Patents

Description

  The present invention relates to a railway vehicle having an aerodynamic brake.

  Aerodynamic brakes using air resistance are widely used in aerospace fields such as aircraft and rockets. In recent years, application of this aerodynamic brake to railway vehicles has been studied. Since the aerodynamic brake works effectively in a high speed range, it is assumed that the aerodynamic brake is mainly used as a brake for emergency stop in a high speed vehicle such as a bullet train or a linear motor car (for example, see Patent Document 1).

JP 2005-41325 A

  However, the aerodynamic brakes for railway vehicles that have been developed so far have a problem that the deceleration at 350 km / h or less is low as compared with the effectiveness in the high speed range.

  Further, it is considered that the drag (braking force) increases as the area of the aerodynamic brake plate increases. For this reason, in order to obtain a larger drag, it is desirable to increase the size of the aerodynamic brake plate. However, a railroad vehicle has a vehicle limit, and the size of the aerodynamic brake plate is limited due to the cabin space and the like. In addition, when the aerodynamic brake plate is enlarged, the discharge vortex from the aerodynamic brake plate is increased, so that it is likely to cause a problem in traveling safety, and there is a concern about the influence on ground facilities (such as overhead wires). Further, the mechanism for appearing / storing the aerodynamic brake plate becomes large, which causes a problem of maintainability. In addition, when a structure in which the aerodynamic brake plate is housed inside the vehicle is adopted, a problem of storage space may occur.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to realize a new aerodynamic brake for a railway vehicle that can obtain a large drag as a whole vehicle while being a smaller aerodynamic brake plate. That is.

The first form for solving the above problem is
An aerodynamic brake plate configured to appear / store on the roof of the vehicle (for example, the aerodynamic brake plate 20 in FIG. 1) is arranged in a line at intervals of 1 m to 5 m in the vehicle front-rear direction.
The aerodynamic brake plate has a height h that satisfies “0.2 ≦ (h / δ) ≦ 0.5 (δ is the boundary layer thickness of the railway vehicle in the assumed aerodynamic brake use speed range)”.
This is a railway vehicle characterized by that.

  According to the first aspect, the aerodynamic brake plates configured to be able to appear / store on the roof of the railway vehicle are arranged in a line at intervals of 1 m to 5 m in the vehicle front-rear direction. The plate is configured such that the height h satisfies “0.2 ≦ (h / δ) ≦ 0.5”.

  Since there is a boundary layer with a slow flow velocity around the vehicle body of the traveling train, the minimum required height h (specifically, the height h of the aerodynamic brake plate is caused by the presence of this boundary layer. And the height h) satisfying “0.2 ≦ (h / δ)” has been clarified by experiments of the inventors. Further, the drag (brake force) obtained by increasing the height h of the aerodynamic brake plate increases, but the degree of increase is not uniform due to the presence of the boundary layer, and the drag obtained when the height h increases. It was also found that the increase in was moderate. In other words, the height h of the aerodynamic brake plate has an upper limit (specifically, a height h satisfying “(h / δ) ≦ 0.5”) at which drag is efficiently obtained.

  However, when one aerodynamic brake plate is made smaller, the obtained drag becomes smaller. Therefore, by arranging the aerodynamic brake plates in a row, a structure is obtained in which a large drag can be obtained as a whole vehicle. When a plurality of aerodynamic brake plates are arranged in a row, it is necessary to consider “series interference” in which the resistance force obtained by the rear aerodynamic brake plate is reduced by the separation flow of the front brake plate. According to the inventor's experiment, the influence of this series interference can be reduced by arranging the aerodynamic brake plates at a certain distance (specifically, 1 m or more and 5 m or less).

  Since the height h of the aerodynamic brake plate is made lower than that of the prior art, the discharge vortex from the aerodynamic brake plate is reduced, the safety of traveling can be ensured, and the influence on the ground equipment (overhead wire etc.) can be reduced. Furthermore, there is an advantage that the structure for appearing / storing the aerodynamic brake plate can be simplified, the maintainability can be improved, and the storage space can be secured.

Regarding the arrangement interval of the aerodynamic brake plates, as a second form,
The aerodynamic brake plates are arranged in a row at intervals of 1.5 m or more and 2.5 m or less in the vehicle longitudinal direction.
A railway vehicle may be configured.

  An interval of 1.5 m or more and 2.5 m or less is an example of a suitable arrangement interval obtained by the inventors' experiment.

As for the shape of the aerodynamic brake plate, as a third form,
The aerodynamic brake plate has a horizontally long rectangular shape in a projected cross section in the vehicle front direction.
A railway vehicle may be configured.

In addition, the aerodynamic brake plates arranged in a row are not limited to one row, and as a fourth form, the railway vehicle according to any one of the first to third forms,
A plurality of rows of the aerodynamic brake plates in the vehicle longitudinal direction are arranged in the vehicle width direction.
A railway vehicle may be configured.

1 is an external perspective view of a vehicle on which an aerodynamic brake plate is arranged. Sectional drawing with respect to the front-back direction of a vehicle. The enlarged view of an aerodynamic brake board. Schematic diagram of the flow field around the vehicle body. The distribution map of the average velocity near the body surface. The relationship diagram of the height h of an aerodynamic brake board and the effectiveness D obtained. Graph showing the relationship between the arrangement interval r and SIC factor C ₃ aerodynamic brake plate. Graph showing the relationship between the sum of the SIC factor C ₃ arrangement interval r and 1 vehicle aerodynamic brake plate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the applicable embodiment of the present invention is not limited to this.

[Overview]
FIG. 1 is an external perspective view of a railway vehicle 10 on which an aerodynamic brake plate is arranged. FIG. 2 is a vertical sectional view with respect to the front-rear direction of the railway vehicle 10 and shows the use of the aerodynamic brake. FIGS. 1 and 2 show an example in which an intermediate vehicle of a Shinkansen is targeted as a railway vehicle.

  As shown in FIGS. 1 and 2, in the present embodiment, a plurality of aerodynamic brake plates 20 are arranged on the roof of the vehicle 10. Specifically, a plurality of rows of aerodynamic brake plates 20 are installed in the vehicle width direction, with a plurality of rows arranged in a row at a predetermined arrangement interval r in the vehicle front-rear direction (traveling direction). Yes. The number m of installed aerodynamic brake plates 20 is determined by the total length of the vehicle, the arrangement interval r, and the like, and the number of rows is determined by the lateral width l of the aerodynamic brake plate 20. 1 and 2 show an example in which ten aerodynamic brake plates 20 are arranged in two rows as one row.

  These aerodynamic brake plates 20 are stored horizontally on the roof when not in use, and are configured to appear by being erected so as to be substantially perpendicular to the traveling direction of the train when in use. Has been.

  In addition, as shown in FIG. 2, the aerodynamic brake plate 20 is configured and arranged in a size that fits within the specified vehicle limit 12 during use. In addition, the aerodynamic brake plate 20 is disposed symmetrically with respect to the vehicle center when viewed from the front. Further, the total of the widths l of a plurality of (two in FIG. 2) aerodynamic brake plates 20 arranged in the vehicle width direction is 1/2 or more with respect to the vehicle limit width W (more preferably 2 / 3 or more).

  3 is an enlarged view of one aerodynamic brake plate 20, FIG. 3 (a) is a front view, and FIG. 3 (b) is a side sectional view. The aerodynamic brake plate 20 has a horizontally long rectangular shape with a height h and a width l when viewed from the front. In addition, the aerodynamic brake plate 20 has a lower end fixed to a rotating shaft 22 that is horizontally installed in the vehicle width direction and is fixedly installed in an opening formed in the roof of the vehicle. In use, the aerodynamic brake plate 20 is driven upright by rotating the rotating shaft 22 by the drive motor 24. Further, the aerodynamic brake plate 20 is fixed so as not to move by a lock mechanism (not shown) at the time of storage and at the time of appearance.

式（１）において、「ρ_０」は空気密度、「Ａ」は空力ブレーキ板２０の正面投影断面積、「Ｃ_Ｄ」は抗力係数、「Ｕ」は列車速度、である。 [principle]
Next, the design principle of the height h of the aerodynamic brake plate 20 and the arrangement interval r will be described. First, the drag D acting on one aerodynamic brake plate 20 placed in a uniform flow field is expressed by the following equation (1).

In the equation (1), “ρ ₀ ” is the air density, “A” is the front projected sectional area of the aerodynamic brake plate 20, “C _D ” is the drag coefficient, and “U” is the train speed.

式（２）において、「ｍ」は設置された空力ブレーキ板２０の枚数、「Ｗ」は車両重量、である。 And the deceleration (alpha) obtained from this drag D becomes following Formula (2).

In Expression (2), “m” is the number of installed aerodynamic brake plates 20 and “W” is the vehicle weight.

式（３）において、「Ｃ_１」は、車体周りの流れ場の影響を表す流れ場係数、「Ｃ_３（ｉ）」は、先頭から数えてｉ番目の空力ブレーキ板２０における直列干渉を表す直列干渉係数、である。 Now, in the configuration in which a plurality of aerodynamic brake plates 20 are arranged in a row on the upper surface of the railway vehicle as in this embodiment, the following two points need to be considered when considering the drag D acting on each aerodynamic brake plate 20: There is.
(A) Influence of the flow field around the vehicle body (b) Influence of the aerodynamic brake plate 20 on the rear aerodynamic brake plate 20 (series interference)
The drag D acting on one aerodynamic brake plate 20 in consideration of the above two points is expressed by the following equation (3).

In Expression (3), “C ₁ ” represents a flow field coefficient representing the influence of the flow field around the vehicle body, and “C ₃ (i)” represents series interference in the i-th aerodynamic brake plate 20 counted from the head. Series interference coefficient.

And the deceleration (alpha) obtained in this case becomes following Formula (4).

(A) Influence of the flow field around the vehicle body In high-speed trains such as the Shinkansen, in the speed range where aerodynamic braking is assumed (for example, at a high speed range of 300 km / over), as shown in FIG. A boundary layer flow develops along. FIG. 4 is a diagram showing an outline of the flow field around the vehicle body. In the drawing, the upper side is a top view of the vehicle 10, and the lower side is a side view of the vehicle 10. As shown in FIG. 4, the boundary layer around the vehicle body starts from the laminar boundary layer near the head of the train and transitions downstream to the turbulent boundary layer.

式（５）において、「δ」は境界層厚さ（平均流速ｕが主流速度（具体的には、高速域である３００ｋｍ以上）の９９％に達する厚さ）、「Ｕ」は主流速度（列車速度Ｕ）、「ｎ」はべき指数、である。 In this case, the average flow velocity u (y) at the height y from the vehicle body surface is expressed by the following equation (5).

In Equation (5), “δ” is the boundary layer thickness (the thickness at which the average flow velocity u reaches 99% of the main flow velocity (specifically, 300 km or more in the high speed region)), and “U” is the main flow velocity ( Train speed U), “n” is a power index.

  In the high-speed train, the thickness of the turbulent boundary layer does not vary greatly in the intermediate vehicle, and the thickness δ is estimated to be around 1 m from the experimental results. The power index n is estimated to be about 9.

  FIG. 5 is a diagram showing the distribution of the boundary layer average flow on the vehicle body surface in the vicinity of the intermediate vehicle. FIG. 5 shows the relationship between the height y from the vehicle body surface and the average flow velocity u, where the vertical axis is the height y from the vehicle body surface and the horizontal axis is the average flow velocity u. However, the mainstream speed (train speed) U is 300 km / h.

As shown in FIG. 5, there is a deceleration region where the average flow velocity u is slower than the potential flow (main flow velocity U) in the vicinity of the vehicle body surface (specifically, the height y from the surface is 1 m or less). To do. For this reason, when a surface having a height h perpendicular to the surface of the vehicle body is considered, the flow rate q passing through the vertical surface is reduced by Δq given by the following equation (6) per unit width.

Here, if Δq = U · δ ^* , it can be considered that the flow is excluded outward by the distance δ ^* given by the following equation (7) by the surface of the vehicle body.

That is, of the height h of the aerodynamic brake plate 20, the height δ ^* from the vehicle body surface is an invalid height that does not contribute to the drag, and the brake obtained in comparison with the case where the aerodynamic brake plate 20 is placed in a uniform flow field. The power is reduced. Flow field coefficient C ₁ is representative of the reduction in the braking force.

すなわち、左辺の「Ｃ_Ｄ・Ｃ_１」は、空力ブレーキ板２０の単位面積当たりで得られる抗力（単位抗力）を表しており、この「Ｃ_Ｄ・Ｃ_１」が大きいほど、空力ブレーキの効率が良いといえる。 As described above, the drag D acting on one aerodynamic brake plate 20 in consideration of “the influence of the flow field around the vehicle body” is expressed by the above-described formula (3). The following equation (8) is obtained.

That is, “C _D · C ₁ ” on the left side represents the drag (unit drag) obtained per unit area of the aerodynamic brake plate 20, and the greater this “C _D · C ₁ ”, the greater the efficiency of the aerodynamic brake. Is good.

FIG. 6 shows the result of measuring the drag D acting on the aerodynamic brake plate 20 at that time by changing the height h of the aerodynamic brake plate 20. However, the lateral width l of the aerodynamic brake plate 20 is not changed. In FIG. 6, the horizontal axis represents the ratio “h / δ” of the height h of the aerodynamic brake plate 20 to the boundary layer thickness δ, and the vertical axis represents “C _D · C calculated from the measured drag D. ₁ ”. The boundary layer thickness δ is a boundary layer thickness in a speed range assuming the use of an aerodynamic brake, and a high speed range of 300 km / h or more was assumed in the experiment.

When the height h of the aerodynamic brake plate 20 is lowered, “C _D · C ₁ ” representing the efficiency of the air brake is rapidly reduced by the deceleration region. According to FIG. 6, it can be seen that the height h at which the efficiency of the aerodynamic brake sharply decreases is a height at which “h / δ = 0.2”. Specifically, since the boundary layer thickness δ is about 1 m, the height h is about 0.2 m. On the other hand, as the height h increases, the degree of increase in “C _D · C ₁ ” relative to the degree of increase in the height h decreases. In FIG. 6, “C _D · C ₁ ” increases only slowly even if the height h is higher than a height that satisfies “h / δ = 0.5”. Therefore, in order to make the height h of the aerodynamic brake plate 20 as low as possible without losing the function as an aerodynamic brake, a range satisfying “0.2 ≦ h / δ ≦ 0.5” (specifically, It is appropriate to set in the range of “0.2 m ≦ h ≦ 0.5 m”.

Moreover, from the shape of the graph shown in FIG. 6, Formula (8) can be represented by following Formula (9).

(B) Series interference In this embodiment, a plurality of aerodynamic brake plates 20 are arranged in a row in each vehicle 10. Therefore, although the leading aerodynamic brake plate 20 can generate the maximum drag D, the aerodynamic brake plate 20 behind it reduces the drag because the flow is decelerated due to the separation flow by the front aerodynamic brake plate 20, and the drag decreases. Conceivable. The drag reduction ratio depends on the shape and area A of the aerodynamic brake plate 20, the arrangement interval r of the aerodynamic brake plates 20, the flow field around the vehicle body, etc., but the shape of the aerodynamic brake plate 20 and the flow field around the vehicle body If is determined, the SIC factor C ₃ determined by the height h and the arrangement interval of the aerodynamic brake plate 20.

The drag D acting on one aerodynamic brake plate 20 in consideration of “series interference” is given by the above equation (3). From this equation (3), the drag D _i acting on each aerodynamic brake plate 20 (i = 1, 2,...) Is expressed by the following equation (10).

From the ratio of these drag forces D1 and Di, the serial interference coefficient C3 (i) of the i-th aerodynamic brake plate 20 is expressed by the following equation (11). However, the serial interference coefficient C3 (1) of the leading (i = 1) aerodynamic brake plate 20 is “1”.

FIG. 7 shows the result of measuring the drag D acting on each aerodynamic brake plate 20 at the time when the arrangement interval r between the two aerodynamic brake plates 20 is changed. However, the height h of each aerodynamic brake plate 20 is the same. 7, the horizontal axis is the ratio to the height h of the arrangement interval r, and the vertical axis is calculated from the drag D _1, D _i measured with it Re of the aerodynamic brake plate 20, the rear aerodynamic brake This is the series interference coefficient C ₃ of the plate 20.

According to FIG. 7, when the arrangement interval r is small (narrow), the series interference coefficient C ₃ decreases rapidly. This is considered to be influenced by the separation flow by the front aerodynamic brake plate 20. On the other hand, increasing (broad) than the extent there the arrangement interval r, SIC factor C ₃ increases only moderately. This is considered to indicate the possibility that the flow separated by the front aerodynamic brake plate 20 is reattached.

Moreover, from the shape of the graph shown in FIG. 7, Formula (11) can be represented by the following Formula (12).

By the way, the aerodynamic brake force obtained by one vehicle is the sum Dtotal of the drag D obtained by each installed aerodynamic brake plate 20, and is given by the following equation (13).

In railway vehicles, the length of the vehicle is determined as a basic specification. For example, in the case of Shinkansen vehicles, the maximum distance is 25 m. That is, the maximum number m of aerodynamic brake plates 20 that can be installed in one vehicle is determined by the maximum number m = vehicle body length / arrangement interval r. If the arrangement interval r increases, but the drag D obtained in one of the aerodynamic brake plate 20 becomes larger SIC factor C ₃ increases, the maximum number m of the aerodynamic brake plate 20 is reduced. Conversely, if the arrangement distance r becomes shorter, but the drag D which the SIC factor C ₃ obtained in one of the aerodynamic brake plate 20 is smaller decreases, becomes large maximum number of aerodynamic brake plate 20. Therefore, when the sum of the series interference coefficients C ₃ (i) of the respective aerodynamic brake plates 20 is maximized from the formula (13) representing the sum Dtotal of the effectiveness D obtained in one vehicle, the drag sum Dtotal is maximized. It can be said.

8 changes the arrangement interval r, is 1 result of calculating the sum of the SIC factor C ₃ of the vehicle component at that time. However, the height h of the aerodynamic brake plate 20 is 0.2 m. 13, the horizontal axis is the arrangement interval r, and the vertical axis is the sum of the SIC factor C _3.

According to FIG. 8, when the arrangement interval r is 2.0 m, the total sum of the series interference coefficients C ₃ , that is, the total sum Dtotal of the drag D obtained in one vehicle becomes maximum. Then, from the total sum Dtotal of efficacy D obtained, the obtained deceleration α can be calculated using Equation (4).

  Conversely, if the required deceleration rate α is given as a design requirement, the required air brake force (the total sum Dtotal of the drag D) can be calculated from the equation (4), and then from the equation (13), The required height h and arrangement interval r can be calculated.

[Example]
Next, an embodiment to which the above principle is applied will be described. In this embodiment, the vehicle 10 is a bullet train. The body length of a general Shinkansen vehicle is “25 m”.

  First, the aerodynamic brake plate 20 has a horizontally long rectangular shape with a height h of “0.2 m”. Then, ten aerodynamic brake plates 20 arranged with an arrangement interval r of “2 m” are arranged in a row on the roof of each vehicle 10 in two rows in the vehicle width direction. That is, a total of 20 aerodynamic brake plates 20 are arranged per vehicle. With this configuration, the aerodynamic braking force obtained per vehicle is maximized from the calculation result shown in FIG.

[Action / Effect]
Thus, in the present embodiment, a plurality of aerodynamic brake plates 20 having a height h are arranged in a plurality of rows on the roof of the vehicle 10 with an arrangement interval r. The height h is determined so as to satisfy “0.2 ≦ (h / δ) ≦ 0.5” so as to be as low as possible without losing the function as the aerodynamic brake. An appropriate arrangement interval r is determined. In particular, the case where the height h is set to 0.2 m and the arrangement interval r is set to 2 m is preferable.

  In this way, the height h of the aerodynamic brake plate is made lower than before, so that the vortex released from the aerodynamic brake plate is reduced and driving safety can be ensured, and to ground equipment (overhead wire etc.) Can reduce the effects of Furthermore, there is an advantage that the structure for the appearance / storage printing of the aerodynamic brake plate can be simplified, the maintainability can be improved, and the storage space can be secured. Further, since the height h is low and the drag D obtained as one aerodynamic brake plate 20 is small, a plurality of aerodynamic brake plates 20 are installed, so that the overall knitting as a whole has a greater drag (braking force) than before. Is obtained.

[Modification]
Note that embodiments to which the present invention can be applied are not limited to the above-described embodiments, and it is needless to say that the embodiments can be appropriately changed without departing from the spirit of the present invention.

(A) Height h of the aerodynamic brake plate 2
For example, in the above-described embodiment, the height h of the aerodynamic brake plate 20 is set to “0.2 m”, but any other height can be used as long as the height h satisfies “0.2 ≦ h / δ ≦ 0.5”. good. As described with reference to FIG. 6, this is a range determined from the change in “C _D · C ₁ ” representing the efficiency of the air brake with respect to the change in the height h of the aerodynamic brake plate 20.

(B) Arrangement interval r of aerodynamic brake plates 20
In the above-described embodiment, the arrangement interval r of the aerodynamic brake plates 20 is set to “2 m”, but may be determined in a range of “1 m ≦ r ≦ 5 m”. This range is a range of values assumed as the arrangement interval r in the measurement shown in FIGS.

Furthermore, it is more preferable that the arrangement interval r is determined in the range of “1.5 m ≦ r ≦ 2.5 m”. This is a range including “2 m” in which the total of the series interference coefficient C ₃ of one vehicle, that is, the aerodynamic braking force obtained by one vehicle is maximized, determined from FIG. This is the range of values for obtaining nearly aerodynamic braking force.

(C) Number of rows of aerodynamic brake plates 20 In the above-described embodiment, two rows of aerodynamic brake plates 20 are arranged. However, three or more rows may be used. In this case, it is desirable that the projection surface of each aerodynamic brake plate 20 when viewed from the front is symmetrical with respect to the center of the vehicle in terms of running stability when using the aerodynamic brake. Further, it is desirable that the total of the lateral widths 1 of the aerodynamic brake plates 20 occupy 1/2 or more (preferably 2/3 or more) with respect to the vehicle limit width W. Moreover, it is good also as 1 row instead of 2 rows.

10 vehicles, 12 vehicle limits 20 aerodynamic brake plates

Claims (4)

As appeared height h from the body surface when the can satisfy "0.2 ≦ (h / δ) ≦ 0.5 (δ is the boundary layer thickness of the rail vehicle in the aerodynamic brake using assumed speed range)" A plurality of aerodynamic brake plates configured to be able to appear / store on the roof of the vehicle are arranged in rows at intervals of 1 m to 5 m in the vehicle front-rear direction at positions where they appear to overlap each other on the projection surface in the vehicle front direction. Thus , the railway vehicle is configured to maximize the total sum of drag of the aerodynamic brake plates arranged in a row . The aerodynamic brake plates are arranged in a row at intervals of 1.5 m or more and 2.5 m or less in the vehicle longitudinal direction.
The railway vehicle according to claim 1. The aerodynamic brake plate has a horizontally long rectangular shape in a projected cross section in the vehicle front direction.
The railway vehicle according to claim 1 or 2. A plurality of rows of the aerodynamic brake plates in the vehicle longitudinal direction are arranged in the vehicle width direction.
The railway vehicle according to any one of claims 1 to 3.

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