CN113962106A - Shaft and method for obtaining position of horizontal pipe in shaft - Google Patents
Shaft and method for obtaining position of horizontal pipe in shaft Download PDFInfo
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- CN113962106A CN113962106A CN202111288378.2A CN202111288378A CN113962106A CN 113962106 A CN113962106 A CN 113962106A CN 202111288378 A CN202111288378 A CN 202111288378A CN 113962106 A CN113962106 A CN 113962106A
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- E—FIXED CONSTRUCTIONS
- E03—WATER SUPPLY; SEWERAGE
- E03F—SEWERS; CESSPOOLS
- E03F3/00—Sewer pipe-line systems
- E03F3/02—Arrangement of sewer pipe-lines or pipe-line systems
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- E—FIXED CONSTRUCTIONS
- E03—WATER SUPPLY; SEWERAGE
- E03F—SEWERS; CESSPOOLS
- E03F5/00—Sewerage structures
- E03F5/04—Gullies inlets, road sinks, floor drains with or without odour seals or sediment traps
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/13—Architectural design, e.g. computer-aided architectural design [CAAD] related to design of buildings, bridges, landscapes, production plants or roads
Abstract
The invention provides a vertical shaft, which comprises a first shaft body and a second shaft body; a water inlet pipe and an air inlet pipe are arranged on one side of the first well body, the air inlet pipe is positioned above the water inlet pipe, a flow outlet pipe is arranged on the other side of the first well body, the flow outlet pipe is vertically connected with the bottom of the first well body, and an elbow section is arranged at the connection position; the second well body is arranged on the outflow pipe and is parallel to the first well body, a horizontal pipe is arranged between the second well body and the first well body, and the air flow forms internal circulation in the first well body and the second well body through the horizontal pipe. The invention also provides a method for obtaining the position of the horizontal pipe in the vertical shaft. The invention can ensure that an internal circulation airflow system is formed in the vertical shaft, and more gas participates in the internal circulation in the vertical shaft while the flow capacity of the vertical shaft is not influenced, thereby more effectively reducing the gas pressure in a downstream pipeline.
Description
Technical Field
The invention relates to the technical field of municipal engineering sewage pipes, in particular to a vertical shaft and a method for acquiring the position of a horizontal pipe in the vertical shaft.
Background
The main reason for the air suction of the vertical shaft is that the water flow is broken and decomposed into a large number of small water drops in the falling process, when the flaky complete water flow is changed into water drops, although the volume of the water flow is not changed, the surface area of the water flow is much larger than that of the original water flow, the contact area between the water flow in the water drop state and the air in the vertical shaft is obviously much larger than that of the original water flow, and therefore more air can be dragged downwards; secondly, the size of the shaft is also the main reason for influencing the air suction of the shaft, and the larger the diameter of the shaft is, the more the air suction is; the higher the shaft, the more complete the break up of the water stream into droplets and the more air is sucked in.
Chinese patent publication No. CN108104242A discloses a straight-flow drop structure for reducing the amount of inhaled gas, which comprises a water inlet pipe, an air inlet, a partition plate, an air pipe, a water pipe and a flow outlet pipe, wherein the partition plate is arranged in the middle of the shaft, an upper orifice is reserved at a distance from the top of the drop structure, and a lower orifice is reserved at a distance from the bottom of the drop structure, so as to form gas circulation inside the drop structure. Although the shaft structure can reduce shaft air suction to a certain extent, most of gas in the shaft can be directly transferred to downstream under the dragging effect of water flow, the gas which can bypass the partition plate and enter the gas pipe section is limited, and when the flow is too large, the gas pipe section can also be crossed with water, so that the purpose of gas circulation cannot be achieved.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a vertical shaft, which can enable more gas to participate in internal circulation in the vertical shaft while not affecting the flow capacity of the vertical shaft, thereby more effectively reducing the gas pressure in a downstream pipeline.
Another object of the invention is to provide a method for obtaining the position of the horizontal tubes in the aforementioned shaft.
According to a first aspect of the object of the present invention, there is provided a shaft comprising a first well and a second well;
a water inlet pipe and an air inlet pipe are arranged on one side of the first well body, the air inlet pipe is positioned above the water inlet pipe, a flow outlet pipe is arranged on the other side of the first well body, the flow outlet pipe is vertically connected with the bottom of the first well body, and an elbow section is arranged at the connection position;
the second well body is arranged on the outflow pipe and is parallel to the first well body, a horizontal pipe is arranged between the second well body and the first well body, and the air flow forms internal circulation in the first well body and the second well body through the horizontal pipe.
Preferably, the second well body is equal to the first well body in height, and the diameter of the second well body is 1/2DSWherein D isSRepresenting a first well body diameter.
Preferably, the length of the horizontal pipe is (2.2-2.7) DSWherein D isSRepresenting a first well body diameter.
Preferably, the diameter of the horizontal pipe is (1/4-2/5) DSWherein D isSRepresenting a first well body diameter.
Preferably, the diameter of the water inlet pipe is 1/2DSThe length of the water inlet pipe is 12 times of the diameter of the water inlet pipe; wherein D isSRepresenting a first well body diameter.
Preferably, the diameter of the air inlet pipe is 1/4DSThe length of the air inlet pipe is 4 times of the diameter of the air inlet pipe; wherein D isSRepresenting a first well body diameter.
Preferably, the diameter of the outlet pipe is equal to the diameter of the first well body, and the length of the outlet pipe is 4DSWherein D isSRepresenting a first well body diameter.
According to a second aspect of the object of the present invention, there is provided a method of obtaining the position of a horizontal pipe in the aforementioned shaft, comprising a first method and a second method;
the first method comprises the following specific steps:
s1, establishing a model
In a vertical shaft with the top ends of the first well body and the second well body sealed, a water inlet pipe orifice is used as an original point, the first well body is sequentially divided into an air pressure nonlinear increasing section and an air pressure linear increasing section, and the original point is downwards a coordinate axis Z in the positive direction;
assuming that the level tube is located at the air pressure nonlinear increasing section, and the level tube is located at the position L from the origin, namely the position where Z is equal to L;
s2, calculating the distribution air pressure
Respectively calculating the air pressure P at the joint of the first well body and the horizontal pipe according to the established modelLAnd the air pressure P 'at the connection part of the second well body and the horizontal pipe'LThe specific calculation process is as follows:
air pressure P at joint of first well body and horizontal pipeLCalculated according to equation (1):
in the formula: h represents the height of the non-linear increasing section of the air pressure, m; l represents the distance of the level tube from the origin, m; dp/dz represents the pressure gradient of the linearly increasing section of pressure, pa/m; p1Denotes the gas pressure at Z0.64 m, pa;
air pressure P 'at the connection part of the second well body and the horizontal pipe'LCalculating according to the formula (2):
in the formula: p6Represents the first well body bottom gas pressure, pa; k is a radical ofdRepresenting the loss coefficients of the second well body and the joint of the first well body and the horizontal pipe section; f represents the friction coefficient of the well wall of the second well body; dCRepresents the diameter of the second well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
represents the average gas velocity in the second well, m/s; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3(ii) a H represents the height from the water inlet pipe to the water outlet pipe, and m;
wherein, P1Calculating according to the formula (3):
in the formula: paDenotes atmospheric pressure, pa; p1Denotes the gas pressure at Z0.64 m, pa; kILoss factor of air inflow at the air inlet; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3；
The average flow velocity of the gas in the gas inlet pipe is m/s;
dp/dz is calculated according to equation (4):
in the formula: qwM is the amount of the inflow3/s；CdTaking 0.4 as a dragging coefficient when the water drop falls; d-2 represents the diameter of the water drop, mm; v ═ 6 denotes the average speed at which the water droplets fall, m/s; dsDiameter of the first well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
P6calculating according to the formula (5):
in the formula: h represents the height from the water inlet pipe to the water outlet pipe, and m; k is a radical oftRepresenting the loss coefficient of the elbow section water flow when falling and colliding;
Va、
and
the relationship between the three is shown as formula (6) and formula (7):
in the formula: dIDenotes the diameter of the inlet pipe, m; dsDiameter of the first well body, m; dCRepresents the diameter of the second well body, m;
s3, determining the critical position
When the gas in the horizontal tube is just in critical state, the gas pressure P at two sides of the horizontal tubeLAnd P'LIs as in equation (8):
PL＝P'L (8)
calculating to obtain an L value, and verifying the L value, wherein the point position L is the critical position of the horizontal tube if the L value is positioned in the air pressure nonlinear growth section; if the L value is outside the non-linear increasing section of the air pressure, selecting the second method to obtain the L value again;
s4, determining the position of the horizontal pipe when the internal circulation airflow can be formed
When the horizontal pipe is at the critical position or is placed at any position between the critical position and the top end of the vertical shaft, the airflow in the vertical shaft can form internal circulation airflow;
the second method comprises the following specific steps:
s1, establishing a model
In a vertical shaft with the top ends of the first well body and the second well body sealed, a water inlet pipe orifice is used as an original point, the first well body is sequentially divided into an air pressure nonlinear increasing section and an air pressure linear increasing section, and the original point is downwards a coordinate axis Z in the positive direction;
assuming that the level tube is located at the air pressure linear increasing section, and the level tube is located at the position L from the origin, namely, the position Z is equal to L;
s2, calculating the distribution air pressure
Respectively calculating the air pressure P at the joint of the first well body and the horizontal pipe according to the established modelLAnd the air pressure P 'at the connection part of the second well body and the horizontal pipe'LThe specific calculation process is as follows:
air pressure P at joint of first well body and horizontal pipeLCalculating according to equation (9):
in the formula: h represents the height of the non-linear increasing section of the air pressure, m; l represents the distance of the level tube from the origin, m; dp/dz represents the pressure gradient of the linearly increasing section of pressure, pa/m; p1Denotes the gas pressure at Z0.64 m, pa;
air pressure P 'at the connection part of the second well body and the horizontal pipe'LCalculating according to the formula (2):
in the formula: p6Represents the first well body bottom gas pressure, pa; k is a radical ofdRepresenting the loss coefficients of the second well body and the joint of the first well body and the horizontal pipe section; f represents the friction coefficient of the well wall of the second well body; dCRepresents the diameter of the second well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
represents the average gas velocity in the second well, m/s; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3(ii) a H represents the height from the water inlet pipe to the water outlet pipe, and m;
wherein, P1Calculating according to the formula (3):
in the formula: paDenotes atmospheric pressure, pa; p1Denotes the gas pressure at Z0.64 m, pa; kILoss factor of air inflow at the air inlet; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3；
The average flow velocity of the gas in the gas inlet pipe is m/s;
dp/dz is calculated according to equation (4):
in the formula: qwM is the amount of the inflow3/s；CdTaking 0.4 as a dragging coefficient when the water drop falls; d-2 represents the diameter of the water drop, mm; v ═ 6 denotes the average speed at which the water droplets fall, m/s; dsDiameter of the first well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
P6calculated according to equation (10):
in the formula: h represents the height from the water inlet pipe to the water outlet pipe, and m; k is a radical oftRepresenting the loss coefficient of the elbow section water flow when falling and colliding;
Va、
and
the relationship between the three is shown as formula (6) andformula (7):
in the formula: dIDenotes the diameter of the inlet pipe, m; dsDiameter of the first well body, m; dCRepresents the diameter of the second well body, m;
s3, determining the critical position
When the gas in the horizontal tube is just in critical state, the gas pressure P at two sides of the horizontal tubeLAnd P'LIs as in equation (8):
PL＝P'L (8)
calculating to obtain an L value, and verifying the L value, wherein the point position L is the critical position of the horizontal tube if the L value is positioned in the air pressure linear increasing section; if the L value is outside the linear increasing section of the air pressure, selecting the first method to obtain the L value again;
s4, determining the position of the horizontal pipe when the internal circulation airflow can be formed
When the horizontal tube is at the critical position, or at any position between the critical position and the top of the shaft, the gas flow in the shaft may form an internal circulation gas flow.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the vertical shaft, the second well body connected with the first well body is arranged, the overflowing section and the gas passing section are completely separated, and a water tongue blocking gas circulation is prevented from being formed when water flow enters the first well body, so that the conditions that the pressure difference inside and outside the gas inlet pipe is increased and more external gas is sucked are avoided, the gas entering is controlled from the source, and the quantity of sucked gas is effectively reduced; meanwhile, through the arrangement of the second well body and the horizontal pipe, the gas retention and storage amount is increased, the circulating gas flow in the internal circulating gas flow system is improved, the balance of the pressure difference inside and outside the gas inlet pipe is facilitated, and the gas volume sucked by the first well body is further reduced.
2. According to the invention, by establishing a proper model, the position of the horizontal pipe can be accurately obtained when the internal circulation airflow can be formed, so that the purpose of reducing the entrainment volume can be really achieved by the vertical shaft, the use effect is ensured, the design accuracy is improved, the position of the horizontal pipe can be obtained through accurate calculation during design, the process of repeated verification through tests is avoided, the practical application is better guided, the construction efficiency and the use effect are improved, and the construction and use cost is reduced.
3. According to the vertical shaft, the second shaft body connected with the first shaft body is arranged, the overflowing section and the gas passing section are completely separated, the occupation of the inner space of the first shaft body is avoided, the overflowing capacity of the vertical shaft is guaranteed, the gas cannot be influenced by the flow rate to form internal circulation, the using range is wider, the effect is better, and the vertical shaft has a good industrial prospect.
Drawings
Fig. 1 is a schematic diagram of the construction of a shaft of the present invention.
Figure 2 is a graph of flow versus volumetric suction for the shaft of example 2, a centrally located bulkhead shaft, and the original shaft.
Description of reference numerals: 10. a first well body; 20. a second well body; 30. a water inlet pipe; 40. an air inlet pipe; 50. a discharge pipe; 60. bending an elbow section; 70. a horizontal tube.
Detailed Description
In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings.
In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways.
The invention provides a vertical shaft, which is characterized in that an overflowing section and a gas passing section are completely separated by arranging a second shaft body connected with a first shaft body, so that the entrainment of gas is reduced, the internal circulation of gas can be ensured by obtaining the position of a horizontal pipe, the gas can reach the practical application well, and the construction efficiency and the use effect are improved.
In a particular embodiment, as shown in fig. 1, the shaft comprises a first shaft 10 and a second shaft 20.
One side of the first well body 10 is equipped with inlet tube 30 and intake pipe 40, intake pipe 40 is located the top of inlet tube 30, and the opposite side of the first well body 10 is equipped with out flow tube 50, it is connected with the bottom of the first well body is perpendicular to go out flow tube 50, and the junction is equipped with elbow section 60.
The second well body 20 is arranged on the outflow pipe 50, the second well body 20 is parallel to the first well body 10, a horizontal pipe 70 is arranged between the second well body and the first well body, and the air flow forms internal circulation in the first well body 10 and the second well body 20 through the horizontal pipe 70.
In the preferred embodiment, the second well 20 is at the same height as the first well 10, and has a diameter of 1/2DSWherein D isSRepresenting a first well body diameter.
In a preferred embodiment, the length of the horizontal tube 70 is (2.2-2.7) DSWherein D isSRepresenting a first well body diameter.
In a preferred embodiment, the diameter of the horizontal tube 70 is (1/4-2/5) DSWherein D isSRepresenting a first well body diameter.
In the preferred embodiment, the inlet pipe 30 has a diameter of 1/2DSThe length of the water inlet pipe is 12 times of the diameter of the water inlet pipe; wherein D isSRepresenting a first well body diameter.
In another preferred embodiment said inlet pipe 30 is 1.28m from the top of the shaft.
In the preferred embodiment, the diameter of the inlet tube 40 is 1/4DSThe length of the air inlet pipe is 4 times of the diameter of the air inlet pipe; wherein D isSRepresenting a first well body diameter.
In another preferred embodiment, the intake duct 40 is 0.2m from the top of the shaft.
In the preferred embodiment, the outlet tube 40 has a diameter equal to the diameter of the first well body and has a length of 4DSWherein D isSRepresenting a first well body diameter.
In another preferred embodiment, there is provided a method of obtaining the position of a horizontal pipe in the aforementioned shaft, comprising a first method and a second method;
the first method comprises the following specific steps:
s1, establishing a model
In the vertical shaft that first well body and second well body top all are sealed to the water inlet pipe mouth is the initial point, divide into atmospheric pressure nonlinear growth section and atmospheric pressure linear growth section with first well body in proper order, and the initial point is the coordinate axis Z of positive direction downwards.
Assume that the level vial is located at the gas pressure non-linear growth section and that the level vial is located at L from the origin, i.e., at Z ═ L.
S2, calculating the distribution air pressure
Respectively calculating the air pressure P at the joint of the first well body and the horizontal pipe according to the established modelLAnd the air pressure P 'at the connection part of the second well body and the horizontal pipe'LThe specific calculation process is as follows:
air pressure P at joint of first well body and horizontal pipeLCalculated according to equation (1):
in the formula: h represents the height of the non-linear increasing section of the air pressure, m; l represents the distance of the level tube from the origin, m; dp/dz represents the pressure gradient of the linearly increasing section of pressure, pa/m; p1Denotes the air pressure at 0.64m, pa.
Air pressure P 'at the connection part of the second well body and the horizontal pipe'LCalculating according to the formula (2):
in the formula: p6Represents the first well body bottom gas pressure, pa; k is a radical ofdRepresenting the loss coefficients of the second well body and the joint of the first well body and the horizontal pipe section; f represents the friction coefficient of the well wall of the second well body; dCRepresents the diameter of the second well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
represents the average gas velocity in the second well, m/s; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3(ii) a H represents the height of the inlet pipe to the outlet pipe, m.
Wherein, P1Calculating according to the formula (3):
in the formula: paDenotes atmospheric pressure, pa; p1Denotes the gas pressure at Z0.64 m, pa; kILoss factor of air inflow at the air inlet; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3；
Is the average flow velocity of the gas in the inlet line, m/s.
dp/dz is calculated according to equation (4):
in the formula: qwM is the amount of the inflow3/s；CdTaking 0.4 as a dragging coefficient when the water drop falls; d-2 represents the diameter of the water drop, mm; v ═ 6 denotes the average speed at which the water droplets fall, m/s; dsDiameter of the first well body, m; vaRepresenting the average gas flow velocity, m/s, in the region of linear increase in gas pressure in the first well body.
P6Calculating according to the formula (5):
in the formula: h represents the height from the water inlet pipe to the water outlet pipe, and m; k is a radical oftAnd the loss coefficient of the elbow section water flow during falling collision is shown.
Va、
And
the relationship between the three is shown as formula (6) and formula (7):
in the formula: dIDenotes the diameter of the inlet pipe, m; dsDiameter of the first well body, m; dCDenotes the diameter, m, of the second well body.
S3, determining the critical position
When the gas in the horizontal tube is just in critical state, the gas pressure P at two sides of the horizontal tubeLAnd P'LIs as in equation (8):
PL＝P'L (8)
calculating to obtain an L value, and verifying the L value, wherein the point position L is the critical position of the horizontal tube if the L value is positioned in the air pressure nonlinear growth section; and if the L value is positioned outside the non-linear increasing section of the air pressure, selecting the second method to obtain the L value again.
S4, determining the position of the horizontal pipe when the internal circulation airflow can be formed
When the horizontal tube is at the critical position, or at any position between the critical position and the top of the shaft, the gas flow in the shaft may form an internal circulation gas flow.
The second method comprises the following specific steps:
s1, establishing a model
In the vertical shaft that first well body and second well body top all are sealed to the water inlet pipe mouth is the initial point, divide into atmospheric pressure nonlinear growth section and atmospheric pressure linear growth section with first well body in proper order, and the initial point is the coordinate axis Z of positive direction downwards.
Assume that the level vial is located at the linearly increasing section of gas pressure and that the level vial is located at L from the origin, i.e., at Z ═ L.
S2, calculating the distribution air pressure
Respectively calculating the air pressure P at the joint of the first well body and the horizontal pipe according to the established modelLAnd the air pressure P 'at the connection part of the second well body and the horizontal pipe'LThe specific calculation process is as follows:
air pressure P at joint of first well body and horizontal pipeLCalculating according to equation (9):
in the formula: h represents the height of the non-linear increasing section of the air pressure, m; l represents the distance of the level tube from the origin, m; dp/dz represents the pressure gradient of the linearly increasing section of pressure, pa/m; p1Denotes the air pressure at 0.64m, pa.
Air pressure P 'at the connection part of the second well body and the horizontal pipe'LCalculating according to the formula (2):
in the formula: p6Represents the first well body bottom gas pressure, pa; k is a radical ofdRepresenting the loss coefficients of the second well body and the joint of the first well body and the horizontal pipe section; f represents the friction coefficient of the well wall of the second well body; dCRepresents the diameter of the second well body, m; vaIndicating gas pressure flow in the first wellAverage gas flow velocity in the growth zone, m/s;
represents the average gas velocity in the second well, m/s; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3(ii) a H represents the height of the inlet pipe to the outlet pipe, m.
Wherein, P1Calculating according to the formula (3):
in the formula: paDenotes atmospheric pressure, pa; p1Denotes the gas pressure at Z0.64 m, pa; kILoss factor of air inflow at the air inlet; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3；
Is the average flow velocity of the gas in the inlet line, m/s.
dp/dz is calculated according to equation (4):
in the formula: qwM is the amount of the inflow3/s；CdTaking 0.4 as a dragging coefficient when the water drop falls; d-2 represents the diameter of the water drop, mm; v ═ 6 denotes the average speed at which the water droplets fall, m/s; dsDiameter of the first well body, m; vaRepresenting the average gas flow velocity, m/s, in the region of linear increase in gas pressure in the first well body.
P6Calculated according to equation (10):
in the formula: h represents the height from the water inlet pipe to the water outlet pipe, and m; k is a radical oftWater for representing elbow sectionLoss factor when streams fall and collide.
Va、
And
the relationship between the three is shown as formula (6) and formula (7):
in the formula: dIDenotes the diameter of the inlet pipe, m; dsDiameter of the first well body, m; dCDenotes the diameter, m, of the second well body.
S3, determining the critical position
When the gas in the horizontal tube is just in critical state, the gas pressure P at two sides of the horizontal tubeLAnd P'LIs as in equation (8):
PL＝P'L (8)
calculating to obtain an L value, and verifying the L value, wherein the point position L is the critical position of the horizontal tube if the L value is positioned in the air pressure linear increasing section; and if the L value is positioned outside the linear increasing section of the air pressure, selecting the first method to obtain the L value again.
S4, determining the position of the horizontal pipe when the internal circulation airflow can be formed
When the horizontal tube is at the critical position, or at any position between the critical position and the top of the shaft, the gas flow in the shaft may form an internal circulation gas flow.
Because the distribution rule of the air pressure in the shaft, namely below a critical position, the air pressure on one side of the first shaft body is larger than the air pressure on one side of the second shaft body on the same position, because most of water flow is decomposed into water drops in an air pressure linear growth area, most of the air in the first shaft body is dragged to the bottom of the first shaft body by the water drops, and then the local air pressure close to the bottom of the first shaft body is larger than the air pressure on one side of the second shaft body on the same position. On the contrary, above the critical position, the gas pressure on one side of the second well body is larger than that in the first well body, so that the gas can enter the first well body from the well of the second well body through the horizontal pipe, thereby forming an internal circulation gas flow, and the formation of the internal circulation gas flow enables the amount of gas transferred to the downstream to be reduced, and the gas pressure is correspondingly reduced.
For better understanding, the present invention is further described below with reference to specific examples, but the present invention is not limited thereto.
[ example 1 ]
Establishing a coordinate axis Z which takes the tail end of the water inlet pipe 30 as an original point and takes the downward direction as a positive direction as shown in figure 1; the falling height of the water flow from the water inlet pipe 30 is 7.72m, the distance from the lower part of the water inlet pipe to the horizontal pipe is L m, and the diameter D of the air inlet pipe 40IIs 0.1m, the diameter D of the first well 10S0.38m, and the elbow section 60 and outlet tube 50 are each 0.38m in diameter. The top of the shaft is sealed and gas can only enter through the inlet pipe 40 and water flows through the inlet pipe 30 to the first well body 10 and then flows out through the outlet pipe 50, and the outlet pipe 50 is communicated with the atmosphere.
Diameter D of the second well bodyC0.15m, and the length of the horizontal tube 70 is 1 m.
Corresponding to, P1For the control air pressure at the intake pipe, the air pressure at Z ═ 0.64m can be selected.
It should be understood that in practical applications, P varies regardless of the size of the shaft1The corresponding position can be selected to be 0.64 m.
In practical application, for the shaft structure with other heights, the water flow mostly takes a jet flow state when falling from the shaft, the jet flow is completely decomposed into water drops after falling for a certain height, and the height of the section of the water drops completely decomposed from the jet flow is represented as:
h＝100D (11)
in the formula: h represents the height of jet break up, m; d represents the diameter of the jet, m;
when the water flow falls fromThe region corresponding to the height from the jet state to the stage of complete decomposition into water droplets is called a gas pressure nonlinear increasing stage, the region with Z ═ h or less is called a gas pressure linear increasing stage, and the gas pressure gradient of the gas pressure nonlinear increasing stage is approximately regarded as half of the linear increasing stage in calculation, that is, the gas pressure gradient of the linear increasing stage is regarded as the half of the linear increasing stage
In this embodiment, the jet diameter D is about 0.05m, and according to the formula (11), the height h of the jet which is completely decomposed into water droplets is 5m, that is, the region from the origin to 5m downward is the air pressure nonlinear increasing section, and the region from 5m or less to 7.72m is the air pressure linear increasing section.
P6For the gas pressure at the outlet pipe, the outlet pipe is known to be open to the atmosphere, so P6The air pressure at (a) is approximately regarded as 0 pa.
1. Calculating the L value using a first method
The critical position Z of L m where the gas in the level tube can circulate is assumed to be in the non-linear increasing region of the gas pressure.
Equation 1.1 is derived from equations (1), (3) and (4):
wherein k isI＝1.15，ρa＝1.2，Pa＝0pa。
Formula (5) gives formula 1.2:
P6＝0pa，kt＝50。
equation (1.3) from equation (2):
kd＝2.4，f＝0.05。
as can be seen from the formula (8), PL＝P'LThen, subtracting 1.3 from 1.1 gives formula 1.4:
subtracting formula 1.3 from formula 1.2 gives formula 1.5:
and obtaining the formula 1.6 by using the formulas (6) and (7):
and
Ds＝0.38m，DI＝0.1m，Dc＝0.15m
from the above, formula 1.7 is obtained:
conjunctive formula 1.4, formula 1.5 and formula 1.7, resulting in formula 1.8:
formula 1.9 according to formula (4):
V＝6m/s，d＝2mm，Cd＝0.4，ρa＝1.2kg/m3the values of the coefficient m at different flow rates are shown in Table 1.
TABLE 1 coefficient m at different flow rates
Substituting formula 1.9 into formula 1.8, and solving for L and VaSolved L and VaThe values are shown in Table 2.
TABLE 2L and V at different flow ratesaValue of (A)
Obviously, L6.78 m > h 5m, i.e. the critical position of the level vial is outside the non-linear growth section of the gas pressure, which is a conclusion that contradicts the assumption, and is therefore recalculated using the second method.
2. Recalculating the L value using a second method
The critical position Z of L m where the gas in the horizontal pipeline can circulate is assumed to be in the linear increasing region of the gas pressure.
Equation 2.1 is derived from equations (3), (4) and (9):
wherein k isI＝1.15，ρa＝1.2，Pa＝0pa。
Formula (2.2) from formula (10):
P6＝0pa，kt＝50。
equation (2) gives equation 2.3:
kd＝2.4，f＝0.05。
as can be seen from the formula (8), PL＝P'LThen, subtracting 2.3 from 2.1 gives equation 2.4:
subtracting formula 2.3 from formula 2.1 gives formula 2.5:
and obtaining the formula 2.6 by using the formulas (6) and (7):
and
Ds＝0.38m，DI＝0.1m，Dc＝0.15m
from the above, formula 2.7 is obtained:
conjunctive formula 2.4, formula 2.5 and formula 2.7, resulting in formula 2.8:
obtaining formula 2.9 according to formula (4):
V＝6m/s，d＝2mm，Cd＝0.4，ρa＝1.2kg/m3the values of the coefficient m at different flow rates are shown in Table 3.
TABLE 3 values of coefficient m at different flow rates
Substituting equation 2.9 into equation 2.8, and solving for L and VaSolved L and VaThe values are shown in Table 4.
TABLE 4L and V at different flow ratesaValue of (A)
Obviously, L is 5.83m > h is 5m, i.e. the critical position of the level vial is in the linearly increasing segment of the gas pressure, assuming that this is true, the calculation is finished.
Thus, the critical location in this embodiment is 5.83m below the origin, and the horizontal tube in this embodiment is 5.83m below the origin, or any location between this location and the top of the shaft, the airflow in the shaft may form an internal circulation airflow.
[ example 2 ]
On the basis of example 1, the horizontal tube was positioned 5.83m below the origin, the entrainment of gas in the shaft was examined, and in comparison with the shaft provided with the central partition and the original shaft, it can be seen from table 5 and fig. 2 that the shaft in example 2 has a significantly lower entrainment of ambient gas, which on average reduces the entrainment by about 66.8% more than the shaft provided with the partition, so that the shaft with the gas flow well and the horizontal tube in example 2 is more capable of reducing the gas pressure downstream of the pipeline.
TABLE 5 vertical shaft entrainment air quantity contrast
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.
Claims (8)
1. A shaft comprising a first shaft body and a second shaft body;
a water inlet pipe and an air inlet pipe are arranged on one side of the first well body, the air inlet pipe is positioned above the water inlet pipe, a flow outlet pipe is arranged on the other side of the first well body, the flow outlet pipe is vertically connected with the bottom of the first well body, and an elbow section is arranged at the connection position;
the second well body is arranged on the outflow pipe and is parallel to the first well body, a horizontal pipe is arranged between the second well body and the first well body, and the air flow forms internal circulation in the first well body and the second well body through the horizontal pipe.
2. The shaft of claim 1 wherein the second well is equal in height to the first well and has a diameter of 1/2DSWherein D isSRepresenting a first well body diameter.
3. Shaft according to claim 1, characterized in that the length of the horizontal tubes is (2.2-2.7) DSWherein D isSRepresenting a first well body diameter.
4. Shaft according to claim 1 or 3, characterized in that the horizontal tubes have a diameter (1/4-2/5) DSWherein D isSRepresenting a first well body diameter.
5. Shaft as claimed in claim 1, characterized in that the diameter of the inlet pipe is 1/2DSThe length of the water inlet pipe is 12 times of the diameter of the water inlet pipe; wherein D isSRepresenting a first well body diameter.
6. Shaft as claimed in claim 1, characterised in that the diameter of the air inlet pipe is 1/4DSThe length of the air inlet pipe is 4 times of the diameter of the air inlet pipe; wherein D isSRepresenting a first well body diameter.
7. Shaft according to claim 1, characterized in that the outlet pipe has a diameter equal to the diameter of the first shaft body and has a length of 4DSWherein D isSRepresenting a first well body diameter.
8. A method of obtaining the position of a horizontal tube in a shaft according to any one of claims 1-7, comprising a first method and a second method;
the first method comprises the following specific steps:
s1, establishing a model
In a vertical shaft with the top ends of the first well body and the second well body sealed, a water inlet pipe orifice is used as an original point, the first well body is sequentially divided into an air pressure nonlinear increasing section and an air pressure linear increasing section, and the original point is downwards a coordinate axis Z in the positive direction;
assuming that the level tube is located at the air pressure nonlinear increasing section, and the level tube is located at the position L from the origin, namely the position where Z is equal to L;
s2, calculating the distribution air pressure
Respectively calculating the air pressure P at the joint of the first well body and the horizontal pipe according to the established modelLAnd the air pressure P 'at the connection part of the second well body and the horizontal pipe'LThe specific calculation process is as follows:
air pressure P at joint of first well body and horizontal pipeLCalculated according to equation (1):
in the formula: h represents the height of the non-linear increasing section of the air pressure, m; l represents the distance of the level tube from the origin, m; dp/dz represents the pressure gradient of the linearly increasing section of pressure, pa/m; p1Denotes the gas pressure at Z0.64 m, pa;
air pressure P 'at the connection part of the second well body and the horizontal pipe'LCalculating according to the formula (2):
in the formula: p6Represents the first well body bottom gas pressure, pa; k is a radical ofdRepresenting the loss coefficients of the second well body and the joint of the first well body and the horizontal pipe section; f represents the friction coefficient of the well wall of the second well body; dCRepresents the diameter of the second well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
represents the average gas velocity in the second well, m/s; rhoaGas at room temperature at standard atmospheric pressureBulk density, kg/m3(ii) a H represents the height from the water inlet pipe to the water outlet pipe, and m;
wherein, P1Calculating according to the formula (3):
in the formula: paDenotes atmospheric pressure, pa; p1Denotes the gas pressure at Z0.64 m, pa; kILoss factor of air inflow at the air inlet; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3；Va IThe average flow velocity of the gas in the gas inlet pipe is m/s;
dp/dz is calculated according to equation (4):
in the formula: qwM is the amount of the inflow3/s；CdTaking 0.4 as a dragging coefficient when the water drop falls; d-2 represents the diameter of the water drop, mm; v ═ 6 denotes the average speed at which the water droplets fall, m/s; dsDiameter of the first well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
P6calculating according to the formula (5):
in the formula: h represents the height from the water inlet pipe to the water outlet pipe, and m; k is a radical oftRepresenting the loss coefficient of the elbow section water flow when falling and colliding;
Va、
and
the relationship between the three is shown as formula (6) and formula (7):
in the formula: dIDenotes the diameter of the inlet pipe, m; dsDiameter of the first well body, m; dCRepresents the diameter of the second well body, m;
s3, determining the critical position
When the gas in the horizontal tube is just in critical state, the gas pressure P at two sides of the horizontal tubeLAnd P'LIs as in equation (8):
PL＝P′L (8)
calculating to obtain an L value, and verifying the L value, wherein the point position L is the critical position of the horizontal tube if the L value is positioned in the air pressure nonlinear growth section; if the L value is outside the non-linear increasing section of the air pressure, selecting the second method to obtain the L value again;
s4, determining the position of the horizontal pipe when the internal circulation airflow can be formed
When the horizontal pipe is at the critical position or is placed at any position between the critical position and the top end of the vertical shaft, the airflow in the vertical shaft can form internal circulation airflow;
the second method comprises the following specific steps:
s1, establishing a model
In a vertical shaft with the top ends of the first well body and the second well body sealed, a water inlet pipe orifice is used as an original point, the first well body is sequentially divided into an air pressure nonlinear increasing section and an air pressure linear increasing section, and the original point is downwards a coordinate axis Z in the positive direction;
assuming that the level tube is located at the air pressure linear increasing section, and the level tube is located at the position L from the origin, namely, the position Z is equal to L;
s2, calculating the distribution air pressure
Respectively calculating the air pressure P at the joint of the first well body and the horizontal pipe according to the established modelLAnd the air pressure P 'at the connection part of the second well body and the horizontal pipe'LThe specific calculation process is as follows:
air pressure P at joint of first well body and horizontal pipeLCalculating according to equation (9):
in the formula: h represents the height of the non-linear increasing section of the air pressure, m; l represents the distance of the level tube from the origin, m; dp/dz represents the pressure gradient of the linearly increasing section of pressure, pa/m; p1Denotes the gas pressure at Z0.64 m, pa;
air pressure P 'at the connection part of the second well body and the horizontal pipe'LCalculating according to the formula (2):
in the formula: p6Represents the first well body bottom gas pressure, pa; k is a radical ofdRepresenting the loss coefficients of the second well body and the joint of the first well body and the horizontal pipe section; f represents the friction coefficient of the well wall of the second well body; dCRepresents the diameter of the second well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
represents the average gas velocity in the second well, m/s; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3(ii) a H represents the height from the water inlet pipe to the water outlet pipe, and m;
wherein, P1Calculating according to the formula (3):
in the formula: paDenotes atmospheric pressure, pa; p1Denotes the gas pressure at Z0.64 m, pa; kILoss factor of air inflow at the air inlet; rhoaGas density in kg/m at standard atmospheric pressure at room temperature3；
The average flow velocity of the gas in the gas inlet pipe is m/s;
dp/dz is calculated according to equation (4):
in the formula: qwM is the amount of the inflow3/s；CdTaking 0.4 as a dragging coefficient when the water drop falls; d-2 represents the diameter of the water drop, mm; v ═ 6 denotes the average speed at which the water droplets fall, m/s; dsDiameter of the first well body, m; vaMeans for expressing an average gas flow velocity, m/s, in a region of linear increase in gas pressure in the first well body;
P6calculated according to equation (10):
in the formula: h represents the height from the water inlet pipe to the water outlet pipe, and m; k is a radical oftRepresenting the loss coefficient of the elbow section water flow when falling and colliding;
Va、
and
the relationship between the three is shown as formula (6) and formula (7):
in the formula: dIDenotes the diameter of the inlet pipe, m; dsDiameter of the first well body, m; dCRepresents the diameter of the second well body, m;
s3, determining the critical position
When the gas in the horizontal tube is just in critical state, the gas pressure P at two sides of the horizontal tubeLAnd P'LIs as in equation (8):
PL＝P′L (8)
calculating to obtain an L value, and verifying the L value, wherein the point position L is the critical position of the horizontal tube if the L value is positioned in the air pressure linear increasing section; if the L value is outside the linear increasing section of the air pressure, selecting the first method to obtain the L value again;
s4, determining the position of the horizontal pipe when the internal circulation airflow can be formed
When the horizontal tube is at the critical position, or at any position between the critical position and the top of the shaft, the gas flow in the shaft may form an internal circulation gas flow.
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| CN202111288378.2A CN113962106A (en) | 2021-11-02 | 2021-11-02 | Shaft and method for obtaining position of horizontal pipe in shaft |
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| CN202111288378.2A CN113962106A (en) | 2021-11-02 | 2021-11-02 | Shaft and method for obtaining position of horizontal pipe in shaft |
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