阅读说明：本技术 匝道排风型单匝道公路隧道通风系统风量分配的计算方法 (Calculation method for air distribution of tunnel ventilation system of ramp air exhaust type single-ramp highway ) 是由 朱祝龙 贺维国 陈洋 金若翃 田峰 陈宜汉 张宇 陈世强 廖荣 袁君正 于 2021-08-16 设计创作，主要内容包括：本发明涉及一种匝道排风型单匝道公路隧道通风系统风量分配计算方法,该方法通过引入匝道与主隧道之间的分风比χ、断面面积比γ以及土建影响因素A、B,计算分风比χ存在的条件下,匝道排风型单匝道公路隧道通风系统总阻力P和直接从出口隧道排风的通风系统总阻力P′差值最小时,分风比χ的值,作为满足通风系统设计要求前提下,实现通风系统装机功耗最小时,匝道与主隧道之间的风量分配,既解决了现有利用匝道排风的单匝道公路隧道通风系统风量分配设置不合理、通风系统能耗高问题；同时,所述的风量分配计算方法可以直接量化匝道通风量与主隧道通风量之间的比值,具有简单、迅速、快捷的特点。(The invention relates to a method for calculating the air distribution of a ventilation system of a ramp air-exhaust type single-ramp road tunnel, which comprises the steps of calculating the difference between the total resistance P of the ventilation system of the ramp air-exhaust type single-ramp road tunnel and the total resistance P' of the ventilation system which directly exhausts air from an outlet tunnel under the condition that the air distribution ratio chi, the cross-sectional area ratio gamma and a civil engineering influence factor A, B are introduced between a ramp and a main tunnel, and calculating the air distribution between the ramp and the main tunnel, wherein the value of the air distribution ratio chi is the minimum value under the premise of meeting the design requirement of the ventilation system, the minimum power consumption of the ventilation system is realized, and the air distribution between the ramp and the main tunnel solves the problems of unreasonable air distribution setting and high energy consumption of the ventilation system of the conventional single-ramp road tunnel ventilation system which utilizes the ramp to exhaust air; meanwhile, the air quantity distribution calculation method can directly quantize the ratio of the ramp air quantity to the main tunnel air quantity, and has the characteristics of simplicity, rapidness and quickness.)

1. A ramp air exhaust type single ramp highway tunnel ventilation system air volume distribution calculation method, the said single ramp highway tunnel ventilation system includes the main tunnel and ramp that forms certain angle arrangement with the main tunnel, the said main tunnel includes the entry tunnel and exit tunnel; the method is characterized in that the air volume distribution calculation method between the ramp and the main tunnel comprises the following steps:

s1, respectively calculating the local resistance P from the inlet tunnel to the ramp ventilation system according to the local resistance calculation formula of the air flow intersection_1～2And local resistance P in the inlet-to-outlet tunnel ventilation system_1～3；

S2, respectively calculating the on-way resistance P of an inlet tunnel in the single-ramp highway tunnel ventilation system₁On-ramp resistance P₂And the on-way resistance P of the exit tunnel₃；

S3, calculating the total ventilation resistance P in the ventilation system of the single-turn road highway tunnel according to the steps S1 and S2, and introducing a wind division ratio chi and a section area ratio gamma of the turns to the main tunnel, wherein: the wind division ratio chi is the ramp ventilation Q₂Required air quantity Q of tunnel₃The ratio of (A) to (B); gamma is the ramp cross-sectional area S₂Cross-sectional area S of main tunnel₃The ratio of (A) to (B);

s4, calculating the total resistance P' in the tunnel ventilation system directly exhausting air from the exit tunnel under the condition of no ramp setting;

s5, calculating a value of the split χ when Δ P ═ P-P' < 0 is minimum in the presence of the split χ, that is: the difference value between the total resistance P of the ventilation system of the ramp air exhaust type single-ramp road tunnel and the total resistance P' of the ventilation system for directly exhausting air from the outlet tunnel is less than zero, and civil engineering influence factors A, B are introduced, wherein:

wherein: lambda [ alpha ]₁The coefficient of on-way friction resistance of the main tunnel is a dimensionless constant; lambda [ alpha ]₂Is the coefficient of on-way frictional resistance of the ramp, and has no dimension constant; l is₁The length of an inlet tunnel in the main tunnel is m; l is₂Is the ramp length in m; d₁Is the equivalent diameter of the main tunnel in m; d₂Is the equivalent diameter of the ramp in m; theta is the included angle between the ramp and the main tunnel and is a unit degree; k_aThe coefficient is a friction resistance influence coefficient and has no dimension constant; rho is air density in kg/m³；υ₃The unit is m/s, and the wind speed is the cross section wind speed of the exit tunnel;

when the value of delta P is minimum, the wind division ratioAccording to the wind dividing ratio x and the wind quantity Q required by the tunnel₃Determining the ramp ventilation Q₂。

2. The method for calculating the air volume distribution of the ramp air-discharge type single-ramp road tunnel ventilation system according to claim 1, wherein in the step S3, after introducing a wind distribution ratio χ and a cross-sectional area ratio γ of a ramp to a main tunnel, a calculation formula of a total ventilation resistance P in the single-ramp road tunnel ventilation system is as follows:

in step S4, the calculation formula of the total resistance P' in the tunnel ventilation system in which the exit tunnel directly exhausts air is as follows:

3. the method for calculating the air volume distribution of the ramp air-discharge type single-ramp road tunnel ventilation system according to claim 1, wherein in step S5, K is_aThe calculation method of (2) is as follows:

wherein in the formula (a), rho is air density and unit kg/m³(ii) a Lambda is the on-way friction resistance coefficient of the main tunnel;

K_athe values of (A) are as follows: when the value of a is 0.002-0.005, K_aThe value is 1; when the value of a is 0.005-0.010, K_aThe value range of (1) to (1.25); when the value of a is 0.010-0.015, K_aThe value range of (1) is 1.25-1.35; when the value of a is 0.015 to 0.020, K_aThe value range of (A) is 1.35-1.50; when a is 0.020 to 0.025, K_aThe value range of (1) is 1.50-1.65; when a is 0.025-0.030, K_aThe value range of (A) is 1.65-1.80.

Technical Field

The invention relates to the field of tunnel ventilation, in particular to a calculation method capable of quickly determining the air distribution of a ramp and a main tunnel under the optimal energy-saving working condition in a ramp air-exhaust type single-ramp highway tunnel ventilation system.

Background

In recent years, a plurality of long tunnels, extra-long tunnels and tunnel groups are built, and the mileage proportion of the tunnels on roads is increased. With the increasing technology of tunnel construction and the demand of operation, the trend of tunnels is that the longer the tunnel is repaired, the wider the tunnel is repaired, and the more difficult and complex the technology is. The traffic engineering of Qinling mountain final south mountain tunnel, Xiamenhang safety tunnel, Qingdao Jiaozhou bay tunnel, Shanghai Changjiang river tunnel bridge and other heavy point engineering is built into traffic vehicles in succession, and has become an important component of urban road, and the traffic vehicles are mutually connected and coordinated with various traffic systems such as urban and rural highways, urban rail traffic, urban roads and the like, thereby showing the functions of relieving traffic pressure, enhancing the urban and rural traffic smoothness and improving traffic environment. Due to the traffic function requirements of the urban tunnel, a large number of entrance and exit ramps need to be built to solve the traffic connection function between urban areas, so that a lot of challenges are added to an existing complex ventilation network system, and a series of problems such as air volume distribution, fan setting, system energy saving and the like are brought.

Tunnel ventilation systems have been energy intensive users during tunnel operation. How to reduce the power of the ventilation system on the premise of ensuring that the designed air volume of all driving areas meets the relevant requirements is always the key point of research in the industry.

For example: the invention discloses an air volume distribution controller of a tunnel construction ventilating duct, which is applied by Cao Congcelery and the like, and solves the problems of prolonged ventilation time, waste of energy consumption and delay of construction period caused by the fact that the air volume required by working faces on two sides of the existing tunnel construction ventilating duct cannot be reasonably distributed by arranging a columnar groove at the bottom of a three-way joint. The invention patent of 'refrigerating equipment and air distribution plates thereof' is applied by the patent of mousse light and the like, the structure of the air channel is simplified, and the cold air to each refrigerating chamber is uniformly distributed through the air distribution plates, so that the air quantity in each air channel branch can be accurately controlled. Pan Dawei and the like apply for the invention patent of 'an underground mine ventilation system and an air distribution method' and solve the problem of simultaneous mining and ventilation of multiple middle sections of an underground mine. The Lifengjun has applied for the invention patent of 'an air volume distribution system', and the air volume distributed to each indoor area is adjusted by controlling the data collected by the system so as to adjust the air quality of each indoor area and improve the utilization rate of the air volume distributed to each indoor area. The Yao Shi army and the like apply for the invention patent of 'air quantity distribution mechanism of the air supply pipe', the deflection angle of the air deflector in the main pipe body can be adjusted according to the requirements, different air quantities are sent to different air outlets, the actual requirements of the site are met, and the use efficiency of an air supply system is improved.

In summary, the substantive content of the above patent is mainly to study the problems of the air volume distribution device, the control method of the control system for feedback regulation of the air volume, and the like; however, the air distribution between the ramp and the main tunnel in the single-ramp highway tunnel ventilation system utilizing the ramp to exhaust air, the influence of civil engineering parameters on the air distribution and the energy-saving calculation of the ventilation system are not explained and solved.

Disclosure of Invention

In order to reduce the power consumption of a fan in a tunnel ventilation system as much as possible on the premise of meeting the ventilation design, the invention provides a calculation method for quickly determining the air distribution between a ramp and a main tunnel on the premise of minimum fan power required by the ventilation system in a ramp air-exhaust type single-ramp highway tunnel ventilation system.

The technical scheme adopted by the invention for solving the technical problems is as follows: a ramp air exhaust type single ramp highway tunnel ventilation system air volume distribution calculation method, the said single ramp highway tunnel ventilation system includes the main tunnel and ramp that forms certain angle arrangement with the main tunnel, the said main tunnel includes the entry tunnel and exit tunnel; the air quantity distribution calculation method between the main tunnel and the ramp comprises the following steps:

s1, respectively calculating the local resistance P from the inlet tunnel to the ramp ventilation system according to the local resistance calculation formula of the air flow intersection_1～2And local resistance P in the inlet-to-outlet tunnel ventilation system_1～3；

S2, respectively calculating the on-way resistance P of an inlet tunnel in the single-ramp highway tunnel ventilation system₁On-ramp resistance P₂And the on-way resistance P of the exit tunnel₃；

S3, calculating the total ventilation resistance P in the single-turn road highway tunnel ventilation system according to the step S1 and the step S2, and introducing a wind division ratio x and a cross-sectional area ratio gamma of a turn and a main tunnel, wherein: the wind division ratio chi is the ramp ventilation Q₂Required air quantity Q of tunnel₃The ratio of (A) to (B); gamma is the ramp cross-sectional area S₂Cross-sectional area S of main tunnel₃The ratio of (A) to (B);

s4, calculating the total resistance P' in the tunnel ventilation system directly exhausting air from the exit tunnel under the condition of no ramp setting;

s5, calculating a value of the split χ when Δ P ═ P-P' < 0 is minimum in the presence of the split χ, that is: the difference value of the total resistance P of the ramp air exhaust type single-ramp highway tunnel ventilation system and the total resistance P' of the ventilation system for directly exhausting air from the outlet tunnel is less than zero, and civil engineering influence factors A, B are introduced, wherein:

wherein: lambda [ alpha ]₁The coefficient of on-way friction resistance of the main tunnel is a dimensionless constant; lambda [ alpha ]₂Is the coefficient of on-way frictional resistance of the ramp, and has no dimension constant; l is₁The length of an inlet tunnel in the main tunnel is m; l is₂Is the ramp length in m; d₁Is the equivalent diameter of the main tunnel in m; d₂Is the equivalent diameter of the ramp in m; theta is the included angle between the ramp and the main tunnel and is a unit degree; k_aThe coefficient is a friction resistance influence coefficient and has no dimension constant; rho is air density in kg/m³；υ₃The unit is m/s, and the wind speed is the cross section wind speed of the exit tunnel;

when the value of delta P is minimum, the wind division ratioAccording to the wind dividing ratio x and the wind quantity required by the tunnel_Q3Determining the ramp ventilation Q₂。

Further, in step S3, after introducing the air dividing ratio χ and the cross-sectional area ratio γ between the ramp and the main tunnel, the calculation formula of the total ventilation resistance P in the single-ramp highway tunnel ventilation system is as follows:

in step S4, the calculation formula of the total resistance P' in the tunnel ventilation system in which the exit tunnel directly exhausts air is as follows:

further, in step S5, K_aThe calculation method of (2) is as follows:

wherein in the formula (a), rho is air density and unit kg/m³(ii) a Lambda is the on-way friction resistance coefficient of the main tunnel;

K_athe values of (A) are as follows: when the value of a is 0.002-0.005, K_aThe value is 1; when the value of a is 0.005-0.010, K_aThe value range of (1) to (1.25); when the value of a is 0.010-0.015, K_aThe value range of (1) is 1.25-1.35; when the value of a is 0.015 to 0.020, K_aThe value range of (A) is 1.35-1.50; when a is 0.020 to 0.025, K_aThe value range of (1) is 1.50-1.65; when a is 0.025-0.030, K_aThe value range of (A) is 1.65-1.80.

Compared with the prior art, the invention has the following advantages and effects:

1. the invention calculates the wind division ratio chi under the condition of existence of the wind division ratio chi by introducing the wind division ratio chi, the section area ratio gamma of the ramp and the main tunnel and the civil engineering influence factor A, B,

when, namely: the difference value between the total resistance P of the ventilation system of the ramp air exhaust type single-ramp road tunnel and the total resistance P' of the ventilation system for directly exhausting air from the outlet tunnel is smaller than the minimum value of zero, and the difference value is used for realizing the air distribution of the ramp and the main tunnel when the minimum installed power consumption of the ventilation system is realized under the condition of meeting the design requirement of the ventilation system, so that the problems of unreasonable air distribution arrangement and high energy consumption of the ventilation system of the conventional single-ramp road tunnel ventilation system for exhausting air by utilizing the ramp are solved; meanwhile, the air volume distribution calculation method can directly quantify the ramp air volumeThe ratio of the air volume to the air volume of the main tunnel is simple, rapid and quick.

2. The invention obtains a calculation formula according to reasoning:

and civil engineering influence factors A, B, wherein the influence of the included angle between the ramp and the main tunnel on the air distribution (namely the air distribution ratio chi) and the total resistance P of the ventilation system in the ramp exhaust type single-ramp highway tunnel ventilation system is mainly analyzed, and the influence of the increase of the cross section area ratio gamma between the ramp and the main tunnel on the air distribution (namely the air distribution ratio chi) and the total resistance P of the ventilation system has important engineering guidance significance for realizing the efficient energy-saving operation of the highway tunnel ventilation system.

3. In summary, the method for calculating the air volume distribution of the single-ramp highway tunnel ventilation system by using ramp air exhaust can directly quantize the ratio of the ramp air exhaust volume to the total air volume, quickly and quickly determine the air volume distribution of a main tunnel and a ramp, and realize the efficient and energy-saving operation of the highway tunnel ventilation system.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural view of a ramp air-discharge type single-ramp highway tunnel ventilation system according to an embodiment of the invention.

Fig. 2 is a curve relationship between an included angle θ between a ramp and a main tunnel and a wind division ratio χ according to the embodiment of the present invention.

Fig. 3 is a graph illustrating an angle θ between a ramp and a main tunnel and a resistance difference Δ P according to an embodiment of the present invention.

Fig. 4 is a graph of the cross-sectional area ratio γ and the wind distribution ratio χ according to the embodiment of the present invention.

Fig. 5 is a graph of the cross-sectional area ratio γ and the resistance difference Δ P according to the embodiment of the present invention.

Description of reference numerals: 1. an entrance tunnel; 2. a ramp; 3. and (6) an exit tunnel.

Detailed Description

The present invention will be described in further detail with reference to examples, which are illustrative of the present invention and are not to be construed as being limited thereto.

Example 1: as shown in fig. 1, the ramp air exhaust type single-ramp highway tunnel ventilation system comprises a main tunnel and a ramp 2 arranged at a certain angle with the main tunnel, wherein the main tunnel comprises an inlet tunnel 1 and an outlet tunnel 3. Wherein the length of the inlet tunnel 1 is L₁(m) cross-sectional area S₁(m²) The ventilation rate is Q1 (m)³/s) and section wind speed is upsilon₁(m/s); the length of the ramp is L₂(m) cross-sectional area S₂(m²) The ventilation rate is Q₂(m³/s) and section wind speed is upsilon₂(m/s), wherein the included angle between the ramp and the main tunnel is theta (DEG); the length of the exit tunnel 3 is L₃(m) cross-sectional area S₁(m²) The ventilation rate is Q₃(m³/s) and section wind speed is upsilon₃(m/s)。

In the ramp air-discharge type single-ramp highway tunnel ventilation system shown in fig. 1, on the premise that the ventilation design is met and the power of a ventilator required by the ventilation system is minimum, the air volume distribution between the ramp and the main tunnel can be quickly determined by the following calculation method, and the specific steps are as follows:

s1, respectively calculating the local resistance P from the inlet tunnel to the ramp ventilation system according to the local resistance calculation formula of the air flow intersection_1～2And local resistance P in the inlet-to-outlet tunnel ventilation system_1～3

Wherein, P_1～2Is 1-2 sections of local resistance, unit: pa; p_1～3Is 1-3 sections of local resistance, unit: pa; ρ is the air density, unit: kg/m³；K_aThe influence coefficient of the tunnel roughness is a dimensionless constant;

coefficient of influence of tunnel roughness K_aThe determination method comprises the following steps:

(a)wherein: lambda is the on-way friction resistance coefficient of the tunnel;

(b) coefficient of influence of tunnel roughness K_aThe values of (A) are selected according to the following table:

a

0.002～0.005

0.005～0.010

0.010～0.015

0.015～0.020

0.020～0.025

0.025～0.030

Ka

1.0

1.1～1.25

1.25～1.35

1.35～1.50

1.50～1.65

1.65～1.80

s2, respectively calculating the on-way resistance P of the inlet tunnel in the single-ramp highway tunnel ventilation system according to a hydromechanics on-way resistance calculation formula₁On-ramp resistance P₂And the on-way resistance P of the exit tunnel₃：

Wherein d is₁As the equivalent diameter of the main tunnel, unit: m; d₂Is the equivalent diameter of the ramp, unit: and m is selected.

S3, calculating the total ventilation resistance P in the single-turn road tunnel ventilation system according to the step S1 and the step S2, and combining the formulas (1) to (5), wherein the total ventilation resistance is as follows:

P＝P_1～2+P_1～3+P₁+P₂+P₃ (6)

according to the relationship between flow and speed:

introducing a wind division ratio chi defined as the ramp ventilation Q₂Required air quantity Q of tunnel₃The ratio of (A) to (B):

the cross-sectional area ratio gamma of the incoming ramp to the main tunnel is defined as the cross-sectional area S of the ramp₂Cross-sectional area S of main tunnel₃The ratio of (A) to (B):

in combination with equations (7) to (11), the following equations (3) to (6) are arranged:

wherein: lambda [ alpha ]₁The coefficient of on-way friction resistance of the main tunnel is a dimensionless constant; lambda [ alpha ]₂Is the coefficient of on-way frictional resistance of the ramp and has no dimensional constant.

S4, calculating a total resistance P' in the tunnel ventilation system exhausting directly from the exit tunnel without a ramp setting:

if the required wind ratio χ exists, the following are:

P_1～2≥0 (16)

P_1～3≥0 (17)

ΔP＝P-P′＜0 (18)

in the formula (18), Δ P is the difference between the total resistance P in the ventilation system of the ramp air-exhausting type single-ramp highway tunnel and the total resistance P' of the ventilation system directly exhausting air from the exit tunnel, and the unit is: pa.

Since cos θ ≦ 1 is always true, equations (16) and (17) are always true.

S5, calculating the value of the wind division ratio chi when the value of the delta P is minimum, and calculating the value of the wind division ratio chi according to the wind division ratio chi and the wind quantity Q required by the tunnel₃Determining the ramp ventilation Q₂；

Introducing a civil engineering influence factor A, B, wherein the calculation formula is as follows:

a is constantly greater than 0;

equation (18) translates to:

the joint solution of equation (19) yields the following limiting requirement:

a-1) when B²-4·A·K_aWhen the content is more than or equal to 0, the following contents are:

a-2) when B²-4·A·K_aIf < 0, the above does not hold.

Further, when B is²-4·A·K_aWhen the value is more than or equal to 0, in order to obtain the minimum value of the delta P, the symmetry of a quadratic equation with one element is considered when

When Δ P is the smallest value.

According toThe ventilation quantity required by the ramp can be calculated.

In this embodiment 1, the fan loader is used to overcome the total resistance in the tunnel due to the ventilation system. Thus, according to P ═ Δ P + P'; since P' is constant, when Δ P is minimal, i.e.: the total resistance in the ventilation system of the air exhaust type single-ramp highway tunnel is minimum; accordingly, the minimum total resistance means that the installed power of the ventilation system is the minimum, and the single-turn road tunnel ventilation system is the most energy-saving. On the basis, the optimal air volume distribution between the main tunnel and the ramp can be quickly determined according to the calculated value of the air division ratio χ.

Example 2: as shown in fig. 1 to 5, the following is an engineering embodiment to which the calculation method of the present invention is applied:

as shown in FIG. 1, taking a single-turn road tunnel as an example, the length L of an entrance tunnel 1₁980m, cross-sectional area S₁＝96.35m²Equivalent diameter 9.88 m; the length of the ramp 2 is L₂530m, cross-sectional area S₂＝50.2m²The equivalent diameter is 7.39m, and the included angle between the ramp 2 and the main tunnel is 15 degrees; the length of the exit tunnel 3 is L₃892m, the main tunnel has air flow rate of Q₃＝770m³And s. The coefficients of on-way friction resistance of the main tunnel and the ramp are lambda₁、λ₂＝0.022。

Respectively calculating:

1) ramp cross-sectional area S₂Cross-sectional area S of main tunnel₃The ratio γ of (d);

γ＝0.521

2) coefficient of influence of frictional resistance:

(a)

(b) coefficient of influence of frictional resistance K_aThe values of (A) are selected according to the following table:

a

0.002～0.005

0.005～0.010

0.010～0.015

0.015～0.020

0.020～0.025

0.025～0.030

Ka

1.0

1.1～1.25

1.25～1.35

1.35～1.50

1.50～1.65

1.65～1.80

obtaining: k_a＝1

(c) Respectively calculating civil engineering influence coefficients

B²-4·A·K_a＝14.45＞0

Therefore, the temperature of the molten metal is controlled,

according toQ₂＝770m³/s*0.32＝246.4m³And/s, namely: the ventilation volume of the ramp is 246.4m³/s。

(1) Further, in order to study the influence of the included angle θ between the ramp and the main tunnel on the split air ratio χ, θ ═ 15, 20, 25, 30, 35, 40, 45, 50} are respectively selected as dependent variables, and χ ═ 0.32, 0.31, 0.31, 0.30, 0.3, 0.28, none are respectively calculated.

Referring to fig. 2, the abscissa is the included angle θ between the ramp and the main tunnel and the unit degree, and the ordinate is the wind division ratio χ. As can be seen from fig. 2, as the included angle between the ramp and the main tunnel increases, the wind dividing ratio decreases accordingly. B appears with increasing angle²-4·A·K_a< 0, where the split ratio is not present. From this, it can be derived: along with the increase of the included angle theta between the ramp and the main tunnel, on the premise of meeting the ventilation design and minimizing the installed power of the ventilation system, the ventilation quantity Q of the ramp₂Gradually decreases.

Next, θ is {15, 20, 25, 30, 35, 40 }; substituting χ into equation (19) to calculate the ramp-to-main tunnel angle θ and total resistance difference Δ P, where χ is {0.32, 0.31, 0.31, 0.30, 0.3, 0.28 }.

Referring to fig. 3, the abscissa is the included angle θ between the ramp and the main tunnel and the unit, and the ordinate is the total resistance difference Δ P and the unit Pa. As can be seen from fig. 3, as the included angle θ between the ramp and the main tunnel increases, the Δ P resistance difference gradually increases, that is: in the ventilation system of the air exhaust type single-ramp highway tunnel, the total resistance P of the system is gradually increased.

(2) Further, in order to study the influence of the cross-sectional area ratio γ of the ramp to the main tunnel on the wind division ratio χ (component distribution), γ ═ {0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8} is selected as a dependent variable, and χ ═ is calculated as absent, 0.24, 0.27, 0.30, 0.34, 0.37, 0.4, 0.42, 0.45, 0.47}, respectively. Referring to fig. 4, the abscissa is the cross-sectional area ratio γ of the ramp to the main tunnel, and the ordinate is the wind division ratio χ. As can be seen from fig. 4, as the section area ratio γ of the ramp to the main tunnel increases, the wind distribution ratio increases.

Then, substituting the value of χ into formula (19), calculating a curve of the cross-sectional area γ and the resistance difference Δ P of the ramp and the main tunnel, referring to fig. 5, where the abscissa is the cross-sectional area ratio γ of the ramp and the main tunnel, and the ordinate is the resistance difference Δ P and the unit Pa. As can be seen from fig. 5, when the ratio γ of the ramp area to the main tunnel cross-sectional area is gradually increased, the total resistance difference Δ P is gradually decreased, i.e., the resistance P of the ventilation system of the exhaust type single-ramp highway tunnel is decreased.

In conclusion, the method for calculating the air quantity distribution of the single-ramp road tunnel ventilation system by using ramp air exhaust can directly quantize the ratio of the ramp air exhaust quantity to the total air quantity of the main tunnel, quickly and quickly determine the air quantity distribution of the main tunnel and the ramp, and realize the efficient and energy-saving operation of the road tunnel ventilation system.

In addition, the invention obtains the following conclusion through data analysis: in the ramp air exhaust type single-ramp highway tunnel ventilation system, air distribution (namely air distribution ratio chi) and total resistance P of the ventilation system are closely related to civil engineering parameters (area and length) of a main tunnel and a ramp and parameters of an included angle between the ramp and the main tunnel. Specifically, as shown in fig. 2 to 5: (a) along with the increase of the included angle between the ramp and the main tunnel, the air distribution ratio is reduced, and the delta P resistance difference value is gradually increased, namely: in the ventilation system of the air exhaust type single-ramp highway tunnel, the total resistance P of the system is gradually increased; (b) along with the increase of the area ratio gamma of the sections of the ramp and the main tunnel, the air distribution ratio is increased, and the total resistance difference delta P is gradually reduced, namely the resistance P of the ventilation system of the air exhaust type single-ramp highway tunnel is reduced. The conclusion has important engineering guidance significance for establishing the high-efficiency and energy-saving exhaust type single-ramp highway tunnel ventilation system.

In addition, it should be noted that the specific embodiments described in the present specification may differ in the shape of the components, the names of the components, and the like. All equivalent or simple changes of the structure, the characteristics and the principle of the invention which are described in the patent conception of the invention are included in the protection scope of the patent of the invention. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.