JP2009196446A - Railroad head car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a head shape of a railroad head car capable of reducing affection of minute pressure wave regardless of presence/absence of a tunnel shock absorbing part. <P>SOLUTION: The railroad head car has a head part (1) in which a cross-sectional area of a vehicle body increases from a tip (1t) of the vehicle body toward a rear-end side of the body in the longitudinal direction. The head part (1) includes a tip region (1a), and a rear region (1b) positioned on a rear-end side of the tip region (1a) in the longitudinal direction and provided with a control platform. In the tip region (1a), an increasing rate of the cross-sectional area per unit length from the tip (1t) toward the rear-end side of the body in the longitudinal direction is larger than that in the rear region (1b). The rear region (1b) is equipped with a pressure gradient changing part (L). The pressure gradient changing part (L) does not exceed 4.0 m at the longest in the longitudinal direction. The increasing rate of the cross-sectional area in the longitudinal direction is once reduced to 0.5 m<SP>2</SP>/m or lower, and then, increased. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to the shape of a railway leading vehicle, and more particularly to a railway leading vehicle that travels at high speed.

  As the speed of railway vehicles increases, various problems occur due to the airflow generated by traveling. One of them is a tunnel micro-pressure wave generated when a railway vehicle passes through a tunnel. Tunnel micro-pressure waves (hereinafter referred to as “micro-pressure waves”) are compression waves generated by the compression of air inside a tunnel when a railway vehicle enters the tunnel at high speed, and the time at a fixed point in the tunnel Proportional to the change in pressure (hereinafter referred to as “pressure gradient”). The micro-pressure wave travels at the speed of sound or near the speed of sound toward the exit of the tunnel in the traveling direction of the railway vehicle. At the tunnel exit, a part of the micro-pressure wave is reflected, and most of the remaining part releases the energy at the tunnel exit in the form of explosive sound or vibration. This explosion sound and vibration cause an environmental (noise) problem that harms the living environment of residents near the tunnel exit.

  The pressure gradient is proportional to the cube of the vehicle speed, and the noise is proportional to the square of the pressure gradient. The problem of noise caused by micro-pressure waves proportional to the pressure gradient is due to the fact that the impact of air compressibility cannot be ignored as the speed of railway vehicles has increased significantly, and countermeasures from an aerodynamic viewpoint are required. It is coming. One of the countermeasures is the vehicle shape of the leading vehicle of the railway vehicle that reduces the micro-pressure wave. For example, a technology has been developed that combines the area where the cross-sectional area is kept almost constant with the increase in the front-projected cross-sectional area (hereinafter referred to as “cross-sectional area”) along the direction of travel to suppress the rise of micro-pressure waves. (For example, Patent Document 1).

  In order to set the vehicle shape for reducing the micro-pressure wave, a combination of various physical quantities, variables, shapes, and the like is required, so that many trial and error methods have been conventionally employed. Recently, a technique has been developed that uses a genetic algorithm as an optimization method to obtain a change in cross-sectional area that reduces micro-pressure waves while satisfying the volume of the cab (for example, Patent Documents 2 and 3).

Further, as a measure for reducing micro-pressure waves, there is a method including a cover (hereinafter referred to as “buffer”) installed at the entrance of a tunnel and having a cross-sectional area of about 1 to 2 times the cross-sectional area of the tunnel. When setting the shape of the leading vehicle described above, if several types of shock absorbers are installed, the shape is optimized for cases where they are not installed, so that the micro pressure wave can be reduced under more conditions A technique for determining the leading shape has also been introduced (for example, Patent Document 3).
JP 11-321640 A JP 2004-66887 A JP 2005-221740 A

  However, when the rise of the micro-pressure wave is suppressed by combining the region where the cross-sectional area is monotonously increased and the region where the cross-sectional area is kept almost constant, the position where the increase rate of the cross-sectional area is large and the next cross-sectional area The distance from the position where the increase rate is large needs to be 15 m or more (for example, Patent Document 1), and this length is extended as the vehicle travel speed increases further. For this reason, the area with a small cross-sectional area expands in the head part of the railway vehicle, in other words, there is a possibility that the general part where the guest room is provided decreases, and the comfort of the guest room is impaired, or the number of passengers that can be accommodated decreases. is there.

  In addition, when optimizing a multi-objective function using a genetic algorithm and obtaining an optimal cross-sectional area change in the shape of the leading railway vehicle (for example, Patent Document 2), or when considering the conditions of buffer work (For example, Patent Document 3), it is necessary to simulate the pressure gradient inside the tunnel close to the actual traveling state.

Therefore, a detailed comparison was made between the optimized cross-sectional area change and the pressure gradient inside the tunnel obtained from the simulation analysis result of the entry into the tunnel without a buffer. The maximum value of the pressure gradient inside the tunnel was generated. The position was different from the simulation in the prior art.
That is, the maximum value of the pressure gradient does not occur at the time corresponding to the position behind the position where the increase rate of the cross-sectional area shown in the prior art is large, but there is a further minute time delay with respect to that position. The same tendency was also observed for tunnels with shock absorbers.

  In order to solve the problem of micro-pressure waves, the present invention is based on a new simulation and based on a fluid environment close to the actual running state, in more detail, the change in the cross-sectional area of the head portion and the pressure gradient in the tunnel. The purpose of the comparison is to provide a railway head vehicle that can reduce the influence of micro-pressure waves regardless of whether there is a buffer work.

In order to solve the above problems, the present invention provides a leading vehicle having a leading portion in which the cross-sectional area of the vehicle body increases from the leading end of the vehicle body toward the rear end side in the longitudinal direction of the vehicle body. The front end region is located on the rear end side in the longitudinal direction of the front end region and includes a driver's cab, and the front end region is closer to the rear end side in the longitudinal direction of the vehicle body than the rear region. The rate of increase of the cross-sectional area per unit length is large, the rear region includes a pressure gradient change portion, and the pressure gradient change portion does not exceed a maximum length of 4.0 m in the longitudinal direction. It is characterized in that the cross-sectional area increase rate is once reduced to 0.5 m ² / m or less and then increased.

  According to the above configuration, in a pressure gradient environment inside a tunnel in which there is a time lag of the pressure gradient change with respect to the rate of increase in the cross-sectional area, the railway vehicle has a pressure when entering the tunnel without a buffer at the top. At the stage before the gradient rises and rises with the increase rate of the cross-sectional area from the front end of the leading portion, the region enters a region where the increase rate of the cross-sectional area is small. As a result, the pressure gradient does not have a sharp peak and gradually decreases after maintaining a value near the maximum value to some extent. Thus, the said structure can hold down the maximum value of a pressure gradient low by the area | region of the longitudinal direction of a vehicle short compared with the past.

  According to the configuration of the present invention, it is possible to provide a railway leading vehicle that can suppress the maximum value of the pressure gradient and reduce the influence of micro-pressure waves in a fluid environment in a tunnel close to an actual phenomenon.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the shape of a railway leading vehicle according to the present embodiment, where (a) is a side view, (b) is a plan view, and (c) is a front view.

  As shown in FIG. 1, the railway leading vehicle has a leading portion 1 and a general portion 2. The leading portion 1 is a region from the tip 1t to the front of the general portion 2, and the cross-sectional area is gradually increased from the tip 1t to the rear side. The leading portion 1 can be divided into a tip region 1a having a large increase rate of the cross-sectional area of the tip (hereinafter referred to as “cross-sectional area increase rate”) and a rear region 1b continuous with the tip region 1a behind the tip region 1a. it can. The rear region 1b includes a driver's cab (driver's cab, not shown), a windshield cover 3 installed on the upper part of the driver's cab, a trolley (not shown), a trolley cover 4 and the like. It is continuous.

[Example 1]
FIG. 2 shows the relationship between the distance from the tip 1t and the cross-sectional area and the relationship between the distance from the tip 1t and the cross-sectional area increase rate in the leading part 1 of the example and the comparative example in this embodiment. In FIG. 2, the cross-sectional area of Example 1 is indicated by a solid line, the cross-sectional area increase rate is indicated by a one-dot chain line, and the cross-sectional area of a comparative example is indicated by a broken line. Incidentally, Example 1 is a railway head vehicle provided with a pressure gradient changing portion L (see arrow in FIG. 2) in a range not exceeding 4 m at a position 2 to 6 m from the tip 1t, and is a comparative example of a railway. The leading vehicle is not provided with such a pressure gradient changing portion L.

The pressure gradient change part L is a continuous area | region which comprises a part of rear part 1b vicinity of the boundary with the front-end | tip area | region 1a in FIG. The rate of increase in the cross-sectional area is reduced from a large value in the tip region 1a to 0.5 m ² / m or less in the pressure gradient change portion L indicated by an arrow in FIG. In this embodiment, the tip region 1a is a region whose distance from the tip 1t is 0 to 2 m, and the rear region 1b is a region whose distance from the tip 1t is 2 m or more (until the front of the general part 2). It is.

The comparative example written together with Example 1 in FIG. 2 is the same as Example 1 from the tip 1t to the portion where the cross-sectional area increase rate decreases to 0.5 m ² / m or less. An increased area is not provided (there is no part of Example 1 that increases again). That is, as shown in the portion where the solid line (Example 1) and the broken line (Comparative Example) do not match in FIG. 2, Example 1 and Comparative Example are a part of the tip side, and Example 1 is a comparative example. The difference is that there is a concave portion that takes a lower value.

By the way, in the part ahead of the distance from the tip 1t from 2m, the part which diverges on the graph of the cross-sectional area between Example 1 and the comparative example occurs, and in Example 1, the concave part described above is formed. In the first embodiment, this is because the cross-sectional area increase rate is once further reduced below 0.5 m ² / m (predetermined value) in the portion where the distance from the tip 1 t is 2 m and beyond, and thereafter, the increase starts to increase. Furthermore, it is starting to decrease further. That is, the shape “forms the rate of increase in the cross-sectional area once increased to 0.5 m ² / m or less and then increases” or “in the vicinity of the boundary with the tip region 1a in the rear region 1b, This is because the rate of increase in the cross-sectional area is once decreased from a predetermined value, then increased from the predetermined value, and further decreased toward the predetermined value.

On the other hand, in this comparative example, although the cross-sectional area increase rate is not shown, the cross-sectional area increase rate is set to about 0.5 m ² / m or less at a portion beyond the distance of 2 m from the tip 1t, and the value is constant. I have to. In addition, about this comparative example, the model experiment is conducted and it is confirmed that the analysis result simulates the experiment result.

  Next, the simulation results of the numerical fluid analysis in the case of entering the tunnel without a shock absorber in Example 1 and the comparative example will be described with reference to the drawings. FIG. 3 is a time waveform of the pressure gradient at the tunnel entrance, and the solid line represents Example 1 and the broken line represents a comparative example. Here, in expressing the change of the pressure gradient, dimensionless processing is performed for the comparison between Example 1 and the comparative example for both time and pressure gradient.

  As shown in FIG. 3, focusing on the vicinity of the maximum value of the pressure gradient, Example 1 has a low peak with respect to the pressure gradient waveform of the comparative example, and the waveform of the peak portion also has a gentle shape. Thus, Example 1 has suppressed the maximum value of the pressure gradient compared with the comparative example, and as a result, the slight pressure wave is also reduced. In addition, the shape of the railroad leading vehicle of Example 1 is set by a method combining an optimization method using a genetic algorithm and a numerical fluid analysis, and is not only in a condition without a buffer work but also in various buffer work conditions. The optimal solution is obtained and the shape is determined so that the micro-pressure wave performance can be obtained.

  Next, the numerical fluid analysis result in consideration of the buffer work condition will be described with reference to the drawings. 4 and 5 are outlines of the buffer works to be analyzed. These correspond to the tunnel buffer works of FIG. 12 (buffer work length 14 m) and FIG. 14 (buffer work length 25 m) of Patent Document 3, and FIG. a) is a side view, and (b) is a front view. FIG. 5 is an outline of a 25 m long buffer work, (a) is a side view, and (b) is a front view. 6 and 7 show the numerical fluid analysis results of the comparative example (broken line) and Example 1 (solid line) with respect to the pressure gradient waveform at the tunnel entrance portion under the tunnel conditions corresponding to FIGS.

  As shown in FIGS. 6 and 7, Example 1 has a low peak with respect to the pressure gradient waveform of the comparative example, and the waveform shape is relaxed. Thus, Example 1 has suppressed the maximum value of the pressure gradient compared with the comparative example. From these, it is thought that Example 1 can obtain the result of suppressing the maximum value of the pressure gradient in any buffer work.

[Examples 2 and 3]
Next, the relationship between the distance from the tip and the cross-sectional area will be described with reference to the drawings with respect to another embodiment in which the shape is changed from the first embodiment. FIG. 8 shows the relationship between the distance from the tip and the cross-sectional area in Examples 2 and 3 and the comparative example.
As shown in FIG. 8, when attention is paid to the rear of the point B where the cross-sectional area of the comparative example (broken line) bends, the increase of the cross-sectional area in Example 2 (solid line) is small compared to the comparative example, and then immediately increases. It is consistent with the comparative example. On the other hand, in Example 3 (dashed line), the increase in the cross-sectional area is small compared with Example 2, and even if it increases thereafter, it changes considerably in comparison with Example 2 in comparison with Example 2. Although the cross-sectional area increase rate is not shown in FIG. 8, in each example, the cross-sectional area increase rate is 0.5 m ^{2 in} a part of the rear of the point B where the cross-sectional area change of the comparative example is bent. / M or less, and the range of the pressure gradient change part L is assumed not to exceed 4 m. Incidentally, in the comparative example, as described above with reference to FIG. 2, the cross-sectional area increase rate is set to about 0.5 m ² / m or less, and the value is made constant.

  Next, an analysis result comparing each example described in FIG. 8 and the comparative example is shown. FIG. 9 is a pressure gradient waveform at the tunnel entrance when each of the examples and comparative examples of FIG. 8 enters the tunnel. Note that FIG. 9 is analyzed under conditions where there is no tunnel buffer. (B) shows the pressure gradient waveform at the time before and after the head portion enters the tunnel, and (a) is an enlarged view of the vicinity of the maximum pressure gradient surrounded by the broken line frame of (b).

  In Example 2 (solid line), as shown in FIG. 9A, the peak of the pressure gradient is lowered compared to the comparative example (broken line), but the pressure gradient waveform is one peak as in the comparative example. Is generated. On the other hand, in Example 3 (one-dot chain line), the peak of the pressure gradient is lowered as compared with the comparative example and Example 2, and two peaks are formed.

  When each example is compared with the comparative example, the increase in the cross-sectional area (cross-sectional area increase rate) is once reduced as in each example, and then the pressure gradient change portion L is increased, thereby increasing the maximum pressure gradient. The value can be suppressed. Then, as shown in the third embodiment, the maximum value of the pressure gradient is reduced as compared with the second embodiment by widening the range in which the increase in the cross-sectional area is changed from small to large.

  From this analysis result, in the rear region 1b of the leading portion 1 (see FIG. 1), the pressure gradient changing portion L that temporarily decreases the cross-sectional area increase rate and increases the cross-sectional area increase rate in the subsequent continuous region. It is one of the effective measures to reduce the influence of micro pressure waves. In designing the train head vehicle, a suitable cross-sectional area increase rate may be set in consideration of the shape of the cab and the like.

[Example 4]
Next, different from the previous embodiments, another embodiment having a plurality of pressure gradient changing sections will be described with reference to the drawings. FIG. 10 shows the relationship between the distance from the tip and the cross-sectional area in the railway head vehicle in the fourth embodiment.

  The fourth embodiment includes a plurality of (two places) pressure gradient changing portions in the rear region 1b of the leading portion 1 (see FIG. 1). Specifically, the pressure gradient changing portion L1 on the left side of FIG. 10 and the pressure gradient changing portion L2 on the right side thereof are separated from the comparative example represented by a broken line, and are in a concave shape.

FIG. 11 is a pressure gradient waveform at the time of tunnel entry by numerical fluid analysis of Example 4 and the comparative example, and (b) shows the pressure gradient waveform at the time before and after the leading portion enters the tunnel, ) Is an enlarged view in the vicinity of the maximum pressure gradient surrounded by a dotted line in (b). In addition, FIG. 11 is analyzing on the conditions without a tunnel buffer work.
In Example 4, the peak of the pressure gradient is lowered as compared with the comparative example, as shown in FIG. 11A, and one peak is generated as the pressure gradient waveform as in the comparative example.
In addition, when applying the shape of the leading vehicle as in the fourth embodiment, since the region is a region including equipment such as a cart in addition to the driver's cab, the conditions for installing these devices are taken into consideration at the time of design.

FIG. 12 summarizes the analysis results of the maximum pressure gradient under the conditions of the shock absorber 14m shown in FIG. 4 and the shock absorber 25m shown in FIG. In addition, in FIG. 12, the maximum pressure gradient of Examples 1-4 is shown by making the maximum pressure gradient of a comparative example into 100%.
When this result was seen, each Example was able to reduce the maximum pressure gradient compared with the comparative example also in the buffer work which changed the conditions with the case where there was no buffer work. The reduction amount of the maximum pressure gradient is about 2 to 7%.

  The preferred embodiments of the present invention have been described above. The present invention is not limited to the one described in the drawings, and design changes can be made without departing from the spirit of the present invention. That is, the three-dimensional shape in each embodiment is determined by optimization in view of the requirements of necessary specifications. By configuring the three-dimensional shape according to the cross-sectional area increase rate provided in the present invention, the three-dimensional shape in the tunnel is reduced. The pressure wave can be reduced.

The shape of the railroad head vehicle which concerns on one Embodiment of this invention is shown, (a) is a side view, (b) is a top view, (c) is a front view. It is the figure which showed the relationship between the distance from a head, and a cross-sectional area in the shape of a railway head vehicle, and the relationship between the distance from a front-end | tip and a cross-sectional area increase rate. 3 is a time waveform of a pressure gradient at a tunnel entrance according to the first embodiment. It is the outline of the buffer work (buffer work length 14m) made into the object of analysis, (a) is a side view, (b) is a front view. It is the outline of the buffer work (buffer work length 25m) made into the object of analysis, (a) is a side view, (b) is a front view. It is a numerical fluid analysis result of the comparative example and Example 1 of the pressure gradient waveform in the tunnel entrance part on the conditions of the tunnel corresponding to FIG. 6 is a comparative example of a pressure gradient waveform at a tunnel entrance portion under a tunnel condition corresponding to FIG. 5 and a numerical fluid analysis result of Example 1. FIG. It is the figure which showed the relationship between the distance from the front-end | tip of Example 2, 3 and a comparative example, and a cross-sectional area. FIG. 9 is a pressure gradient waveform at a tunnel entrance when the railway head vehicle of each of the examples and comparative examples in FIG. 8 enters the tunnel, and (a) is a pressure gradient at a time before and after the head enters the tunnel. A waveform is shown, (b) is an enlarged view near the maximum pressure gradient of (a). It is the figure which showed the relationship between the distance from the front-end | tip of the railway head vehicle in Example 4, and a cross-sectional area. It is a pressure gradient waveform at the time of tunnel entry by numerical fluid analysis of Example 4 and a comparative example, (a) shows the pressure gradient waveform at the time before and after the head part enters the tunnel, (b) It is an enlarged view near a pressure gradient. It is an analysis result of the maximum pressure gradient on the conditions of various tunnel buffer works in Examples 1-4 and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Top part 1a Tip area 1b Rear part 1t Tip 2 General part 3 Windshield cover 4 Carriage cover L Pressure gradient change part

Claims (3)

In the railway leading vehicle having a leading portion where the cross-sectional area of the vehicle body increases from the front end of the vehicle body toward the rear end side in the longitudinal direction of the vehicle body,
The leading portion includes a front end region and a rear region that is located on the rear end side in the longitudinal direction of the front end region and includes a cab.
The tip region has a larger rate of increase in the cross-sectional area per unit length from the tip toward the rear end side in the longitudinal direction of the vehicle body than the rear region,
The rear region includes a pressure gradient changing unit,
The pressure gradient change part is formed so as not to exceed a maximum length of 4.0 m in the longitudinal direction and to increase the rate of increase in the transverse area in the longitudinal direction once decreased to 0.5 m ² / m or less. This is the first train in the railway. In the railway leading vehicle having a leading portion where the cross-sectional area of the vehicle body increases from the front end of the vehicle body toward the rear end side in the longitudinal direction of the vehicle body,
The leading portion includes a front end region and a rear region that is located on the rear end side in the longitudinal direction of the front end region and includes a cab.
The tip region has a larger rate of increase in the cross-sectional area per unit length from the tip toward the rear end side in the longitudinal direction of the vehicle body than the rear region,
The rear region includes a pressure gradient changing unit,
The pressure gradient changing unit is configured to decrease the increase rate of the cross-sectional area once in a vicinity of a boundary with the tip region in the rear region, and then increase the cross-sectional area from the predetermined value, and further increase the direction beyond the predetermined value. The leading railway vehicle, which is formed to decrease toward the railway.   The rail leading vehicle according to claim 1, further comprising a pressure gradient change unit different from the pressure gradient change unit in a rear region on a rear end side of the pressure gradient change unit.

Images