CN112032399B - Metering test and control method for internal pressure reduction flow characteristic of labyrinth disc pressure reducing valve - Google Patents
Metering test and control method for internal pressure reduction flow characteristic of labyrinth disc pressure reducing valve Download PDFInfo
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- CN112032399B CN112032399B CN202010825229.4A CN202010825229A CN112032399B CN 112032399 B CN112032399 B CN 112032399B CN 202010825229 A CN202010825229 A CN 202010825229A CN 112032399 B CN112032399 B CN 112032399B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K37/00—Special means in or on valves or other cut-off apparatus for indicating or recording operation thereof, or for enabling an alarm to be given
- F16K37/0075—For recording or indicating the functioning of a valve in combination with test equipment
- F16K37/0091—For recording or indicating the functioning of a valve in combination with test equipment by measuring fluid parameters
Abstract
The invention discloses a metering test and control method for the pressure reduction flow characteristic inside a labyrinth disc pressure reducing valve. Building a circulating pipeline loop, installing a labyrinth disc pressure reducing valve, and flushing and pressurizing; dividing the flow channel into a plurality of sections of sub-flow channels, and installing a pressure strain gauge and a flowmeter on a longitudinal section; detecting to obtain a pressure value and a flow velocity value, and calculating a harmonic average value; drawing a discrete curve of harmonic mean values at different sections along with the change of inlet pressure, drawing energy dissipation maps corresponding to different inlet pressures, and performing interpolation calculation to determine a critical energy dissipation value; adjusting the opening of the valve and adjusting the number of layers of the labyrinth discs in the labyrinth disc sleeve to obtain an energy dissipation map; and obtaining a real-time energy dissipation value in the dynamic test and comparing the real-time energy dissipation value with the critical energy dissipation value for control. The invention can adaptively adjust test, operate, optimize and control, realize self-elimination of cavitation/erosion failure critical characteristics of the labyrinth disc type pressure reducing valve in a complex service environment, and has high accuracy of a quantitative metering test method.
Description
Technical Field
The invention relates to a metering test and control method in a fluid valve, in particular to a metering test and control method for the internal pressure reduction flow characteristic of a labyrinth disc pressure reducing valve.
Background
The regulating valve plays a role in regulating medium pressure and flow in the process of material conveying in process industry, and is a key part for ensuring normal operation of various reaction equipment, cold exchange equipment and fractionation equipment in modern process industry. In the process of high differential pressure regulation of the existing regulating valve, a medium is easy to cavitate to cause cavitation erosion (cavitation erosion), under the working condition of existence of solid particles, the problem of erosion abrasion failure can also occur, and the combined action of cavitation erosion and erosion abrasion causes great harm to the safe and stable operation of a valve core. In contrast, the labyrinth regulating valve has the characteristics of high pressure drop and high flow speed relative to other valves, and a labyrinth flow channel on a disc of an inner valve core is a core element for generating front and back pressure drops of fluid, so that the labyrinth regulating valve is widely applied to a coal chemical steam pressure reducing valve and a power station boiler feed pump recirculation system. In view of the harsh operating conditions of petrochemical engineering, coal chemical engineering and nuclear power engineering and the ubiquitous high-temperature, high-pressure and even hydrogen-contacting operating conditions, the flash evaporation cavitation phenomenon easily occurs to the valve in the pressure reduction flowing process. The cavitation collapse formed by cavitation can generate local micro high pressure to cause the flow channel on the labyrinth disc to suffer serious damage, thereby causing leakage, seriously influencing the flow control precision and further threatening the normal safe operation of the core unit device. Therefore, it is very urgent to study the pressure reduction flow characteristics inside the labyrinth disk pressure reducing valve and the adjustment and control method thereof, both from the aspects of the sensitivity and control accuracy of the labyrinth valve and the operation reliability and safety of the core unit.
For the pressure reducing flow characteristic inside the labyrinth disk pressure reducing valve, the existing research has made intensive research on the pressure reducing flow characteristic of the labyrinth valve, from the aspects of flow characteristic, cavitation mechanism and the like, for example, the labyrinth flow channels connected in series and parallel are adopted for pressure reduction and flow regulation. The more the labyrinth valve stages are obtained based on numerical simulation, the more stable the pressure reduction is, and for the pressure reduction flow characteristics of labyrinth flow passages with different stages, when the stages reach the critical stages, the pressure reduction benefit obtained by increasing the stages is relatively small. Based on the pressure reduction flow characteristics of labyrinth flow passages with different sizes, the labyrinth flow passages based on combination of flow division and opposite impact are provided in the existing research, along with the increase of the width of an inlet and an outlet, the flow is in an increasing trend, and the outlet pressure and the outlet speed are in a descending trend, so that a novel flow passage structure is designed to meet the circulation requirement. On the basis, research also proposes that a connecting groove is added on the minimum flow valve to optimize a labyrinth flow passage, so that the minimum pressure value of the fluid medium is always greater than the saturated vapor pressure value, and the cavitation phenomenon is avoided.
In summary, the current research mainly aims at the aspects of the flow characteristic, the pressure reduction mechanism and the like of the labyrinth valve, so that a novel flow passage is designed, the size of the flow passage is improved, and an auxiliary device is added to avoid the cavitation phenomenon. However, the existing research is mainly developed based on numerical simulation, an accurate quantitative measurement testing method is lacked for the pressure reduction flow characteristic in a valve core flow passage of the labyrinth valve, and the problems of low control precision and adjustment lag exist in the control of the labyrinth valve based on the numerical simulation.
Disclosure of Invention
In order to overcome the problems of the existing methods in the background technical field, the invention aims to provide a metering test and control method for the internal pressure reduction flow characteristic of a labyrinth disc pressure reducing valve, which can realize real-time dynamic metering monitoring of pressure, flow velocity and energy dissipation in a labyrinth flow passage of the labyrinth pressure reducing valve, thereby providing a control mode for avoiding cavitation/erosion failure of the flow passage of the labyrinth disc, realizing regulation control of a labyrinth disc regulating valve, improving the regulation control precision of the labyrinth disc regulating valve, avoiding cavitation, and being beneficial to prolonging the service life and the safe and stable operation period of the labyrinth disc pressure reducing valve.
In order to achieve the aim of the invention, the technical scheme adopted by the invention is as follows:
the method comprises the following testing and control steps:
1) building a circulating pipeline loop, arranging a test valve pipe section in the middle area of the circulating pipeline loop, installing a labyrinth disc pressure reducing valve in the test valve pipe section, flushing and pressurizing the circulating pipeline loop by using a circulating pump and a pressurizing pump, and ensuring that the inlet pressure of the labyrinth disc pressure reducing valve is between 10.7MPa and 14.7 MPa;
2) for the device installed on the labyrinth disc sleeve, the device is divided into a plurality of sub-flow passages according to the radial flow direction, the middle part of each sub-flow passage is provided with a cross section, and n pressure strain gauges and m flow meters are respectively installed on the inner wall of the flow passage where the longitudinal cross sections of the plurality of sub-flow passages are located;
3) flushing the whole circulating pipeline loop by using a circulating pump, and ensuring that the inlet pressure of the labyrinth disc pressure reducing valve is 10.7MPa through a pressurizing pump and a flow control valve at the downstream of the labyrinth disc pressure reducing valve;
4) in the test process, the n pressure strain gauges and the m flow meters which are arranged on the inner wall of the flow channel are utilized to acquire, analyze and convert in real time to obtain n pressure values and m flow velocity values of the inner wall of the flow channel, and then the harmonic average values of the pressure values and the flow velocity values at the section are respectively calculated:
Wherein N represents the total number of pressure strain gauges/flowmeters, XNThe pressure value/flow velocity value acquired by the Nth pressure strain gauge/flowmeter and obtained through conversion is shown,
representing the harmonic mean value of the pressure values/flow velocity values collected by all the N pressure strain gauges/flowmeters;
5) repeating the step 3), stepping and increasing the inlet pressure of the labyrinth disc pressure reducing valve for multiple times until the inlet pressure reaches 14.7MPa, then obtaining n pressure values, m flow velocity values and harmonic mean values thereof again by utilizing the step 4), and respectively drawing discrete curves of the harmonic mean values at different sections along with the change of the inlet pressure of the labyrinth disc pressure reducing valve;
6) for different sections of the labyrinth disc pressure reducing valve, calculating energy dissipation values of adjacent sections by using the following formula, and drawing energy dissipation maps corresponding to inlet pressures of different discrete labyrinth disc pressure reducing valves:
in the formula: epsilon is an energy dissipation value, rho is the density of the water phase, g is the acceleration of gravity,
the harmonic mean value of the pressure value of each measuring point on the J-th section is shown,
represents the harmonic mean of all m flow velocity values on the jth section,
represents the harmonic mean of all n pressure values on the J-th section;
7) according to the energy dissipation maps corresponding to the inlet pressures of the different discrete labyrinth disc pressure reducing valves established in the step 6), calculating the energy dissipation map corresponding to the inlet pressure of the continuous labyrinth disc pressure reducing valve in an interpolation mode, and determining a critical energy dissipation value [ epsilon ] of a cavitation erosion or erosion damage point of a flow channel in a labyrinth disc sleeve;
8) the valve rod position regulator is used for regulating and controlling the positions of different valve rods so as to regulate the opening of the labyrinth disc pressure reducing valve, regulating the layer number of labyrinth discs in the labyrinth disc sleeve, and testing the layer number of different labyrinth discs in the labyrinth disc sleeve and the energy dissipation pattern in corresponding labyrinth disc runners under the inlet pressure of different labyrinth disc pressure reducing valves;
9) in the dynamic testing process, dynamically monitoring a pressure value converted by a pressure strain gauge in a labyrinth flow channel and a flow rate value converted by a flowmeter, obtaining a real-time energy dissipation value epsilon and comparing the energy dissipation value epsilon with a critical energy dissipation value [ epsilon ]:
if epsilon < [ epsilon ], the valve rod controller is kept unchanged;
if epsilon is more than or equal to epsilon, the valve rod controller adjusts the opening increasing degree and updates and reprocesses the energy dissipation value epsilon until epsilon < [ epsilon ].
The labyrinth disc pressure reducing valve comprises a valve body, a valve seat, a labyrinth disc sleeve, a valve cover, a valve rod, a valve core, a throttling orifice plate and a valve rod position regulator; the top of the valve body is provided with a circular opening, a valve cover is installed in the circular opening, a central through hole is formed in the valve cover in the vertical direction, an upper cavity and a lower cavity are formed in the valve body, the end parts of the two sides of the valve body are provided with a horizontal medium inlet and a horizontal medium outlet, the medium inlet is communicated with the upper cavity of the valve body, and the medium outlet is communicated with the lower cavity of the valve body; the upper cavity and the lower cavity are connected through a through hole, a valve seat is arranged at the through hole, a labyrinth disc sleeve is arranged on the valve seat, and the lower part of the valve cover and the upper part of the labyrinth disc sleeve are mutually sleeved in an interference manner; the valve cover and the labyrinth disc sleeve are both provided with central through holes, and the central through holes of the valve cover and the labyrinth disc sleeve are coaxially and vertically communicated; the valve seat mainly comprises an upper cylinder and a lower cylinder which are coaxial, the diameter of the upper cylinder is larger than that of the lower cylinder, an inverted cone inner cavity is formed in the center of the upper cylinder, a cylindrical inner cavity is formed in the lower cylinder, a throttling orifice plate provided with a vertical throttling hole is arranged on the top end face of the inverted cone inner cavity, the inverted cone inner cavity is communicated with the bottom of a central through hole of the labyrinth disc sleeve through the throttling orifice plate, the inverted cone inner cavity is communicated with the cylindrical inner cavity, orifice plates provided with horizontal partition throttling holes are uniformly distributed between the inverted cone inner cavity and the cylindrical inner cavity, a plurality of fluid guide holes are uniformly distributed on the bottom end face of the cylindrical inner cavity, and the fluid guide holes and the horizontal partition throttling holes are arranged in a staggered mode; the edge of the top surface of the cylinder at the upper part of the valve seat is provided with an annular groove, the edge of the lower end surface of the labyrinth disc sleeve is provided with an annular boss, and the annular boss of the labyrinth disc sleeve is embedded into the annular groove of the valve seat to form connection matching; the middle part of the lower end surface of the labyrinth disc sleeve is provided with an annular groove, and the throttle orifice plate is embedded into the annular groove of the labyrinth disc sleeve; the valve rod penetrates through the central through hole of the valve cover, the lower end of the valve rod penetrates through the central through hole of the valve cover, the rear end part of the valve rod is hinged with a cylindrical valve core, and the upper end of the valve rod penetrates through the central through hole of the valve cover and then is connected with the valve rod position regulator.
A plurality of layers of labyrinth discs are arranged in the middle barrel of the labyrinth disc sleeve from bottom to top, and a plurality of S-shaped horizontal labyrinth flow channels which are communicated in the radial direction are formed in the labyrinth discs.
The S-shaped horizontal labyrinth flow channel is a flow channel bent at a right angle and is divided into a plurality of sections of sub-flow channels according to the radial flow direction, the middle part of each section of sub-flow channel is provided with a cross section, and the inner wall of the cross section is provided with a plurality of pressure strain gauges and a plurality of flow meters along the circumference.
The lower end of the valve cover is provided with an annular concave hole, the upper part of the labyrinth disc sleeve is provided with an annular boss, and the annular boss is sleeved in the annular concave hole to form interference fit.
The valve core is internally provided with one or more supporting radial plates at the center, a circumferential groove is formed around the excircle of the middle upper part of the valve core, and an annular graphite strip is embedded in the circumferential groove.
The annular gap between the periphery of the valve cover and the circular opening of the valve body is internally provided with an annular sealing gasket and an annular pressing ring from bottom to top, the valve cover above the annular pressing ring is externally sleeved with a flange plate, the flange plate is fixedly connected with the outer end face of the circular opening of the valve body through a flange of the valve cover, and the annular sealing gasket and the annular pressing ring are tightly pressed in the annular gap to form sealing.
The valve rod flange is sleeved outside the valve rod above the dust ring, and the valve rod flange is fixedly connected with the outer end face of the valve cover central through hole through a locking nut.
An annular retaining ring, an annular retaining ring and a balance sealing ring are sequentially arranged in an annular gap between the periphery of the top of the valve core connected with the valve rod and the central through hole of the labyrinth disc sleeve from top to bottom.
The invention has the beneficial effects that:
the invention can be used for realizing the operation optimization control of the labyrinth disc type pressure reducing valve and realizing the self-elimination of the cavitation/erosion failure critical characteristic of the labyrinth disc type pressure reducing valve in the complex service environment by detecting the pressure values and the flow velocity values of different area positions in the labyrinth disc type pressure reducing valve and drawing the pressure reduction flow characteristics in the labyrinth disc flow channel corresponding to different inlet pressures of the pressure reducing valve, thereby providing a regulation and control basis for the self-adaptive regulation of the opening of the pressure reducing valve based on the pressure reduction flow characteristics.
The invention is suitable for the optimized design and the optimized operation of the high-pressure-difference labyrinth valve in petrochemical industry, coal chemical industry, nuclear power engineering and the like, and has high precision of the quantitative metering test method and strong practicability of the valve control technology.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Fig. 2 is an enlarged view of the area W in fig. 1.
FIG. 3 is a schematic view of the single-layer labyrinth disk of FIG. 1.
Fig. 4 is a partially enlarged view of the labyrinth disk flow channel a in fig. 3.
Fig. 5 is a graph of maximum pressure values for different longitudinal sections.
Fig. 6 is a pressure average distribution plot for different longitudinal sections.
Fig. 7 is a graph of maximum velocity values for different longitudinal sections.
FIG. 8 is a velocity average profile for different longitudinal sections.
FIG. 9 is a plot of maximum kinetic energy distribution for different longitudinal sections.
FIG. 10 is a plot of the mean value of the kinetic energy of turbulence for different longitudinal sections.
FIG. 11 is a turbulent dissipation diagram of the labyrinth disk flow channel A of FIG. 3.
In the figure: the valve comprises a valve body (1), a valve seat (2), a labyrinth disc sleeve (3), a sealing gasket (4), a pressing ring (5), a valve cover flange (6), a valve cover (7), a packing gland (8), a valve rod flange (9), a dust ring (10), a sealing packing (11), a packing base gasket (12), a valve rod (13), a flange plate (14), a baffle ring (15), a check ring (16), a balance sealing ring (17), a valve core (18), a throttling pore plate (19), a supporting radial plate (20), a valve rod position regulator (21), a medium inlet (22), a medium outlet (23), a labyrinth disc (24) and an annular graphite strip (25).
Detailed Description
The invention is further explained below with reference to the drawings and examples.
As shown in fig. 1 and 2, the labyrinth disc pressure reducing valve includes a valve body 1, a valve seat 2, a labyrinth disc sleeve 3, a valve cover 7, a valve rod 13, a valve core 18, a throttle orifice plate 19 and a valve rod position regulator 21; the top of the valve body 1 is provided with a circular opening, a valve cover 7 is installed in the circular opening, a central through hole is formed in the valve cover 7 in the vertical direction, an upper cavity and a lower cavity are formed in the valve body, the end parts of the two sides of the valve body are provided with a horizontal medium inlet 22 and a horizontal medium outlet 23, the medium inlet 22 is communicated with the upper cavity of the valve body 1, and the medium outlet 23 is communicated with the lower cavity of the valve body 1; the upper cavity and the lower cavity are connected through a through hole, the valve seat 2 is arranged at the through hole, the labyrinth disc sleeve 3 is arranged on the valve seat, and the lower part of the valve cover 7 is in interference fit with the upper part of the labyrinth disc sleeve 3. The lower end of the valve cover 7 is provided with an annular concave hole, the upper part of the labyrinth disc sleeve 3 is provided with an annular boss, and the annular boss is sleeved in the annular concave hole to form interference fit, so that the lower part of the valve cover 7 and the upper part of the labyrinth disc sleeve 3 are mutually sleeved in an interference fit manner. Thus, the circular boss at the upper part of the labyrinth disc sleeve 3 is connected with the groove at the lower part of the valve cover 7 in an embedding way, and the central hole is centered.
The valve cover 7 and the labyrinth disc sleeve 3 are both provided with central through holes, and the valve cover 7 and the central through hole of the labyrinth disc sleeve 3 are vertically and coaxially communicated up and down; disk seat 2 mainly comprises upper portion cylinder and lower part cylinder are coaxial, the cylindrical diameter in upper portion is greater than the cylindrical diameter in lower part, the back taper inner chamber has been seted up at the cylindrical center in upper portion, cylindrical inner chamber has been seted up in the cylinder in lower part, the top end face of back taper inner chamber is equipped with the orifice plate 19 of seting up vertical orifice, the back taper inner chamber is through orifice plate 19 and labyrinth disc sleeve 3's central through-hole bottom UNICOM, back taper inner chamber and cylindrical inner chamber UNICOM, it sets up the orifice plate that the orifice was cut off to the level to be equipped with the equipartition between back taper inner chamber and the cylindrical inner chamber, a plurality of fluid delivery holes are seted up to the bottom terminal surface equipartition of cylindrical inner chamber, and fluid delivery hole and the position dislocation arrangement that the orifice was cut off to the level.
An annular groove with the depth of 4-6 mm is formed in the edge of the top surface of the cylinder at the upper part of the valve seat 2, an annular boss is arranged on the edge of the lower end face of the labyrinth disc sleeve 3, and the annular boss of the labyrinth disc sleeve 3 is embedded into the annular groove of the valve seat 2 to form connection matching; the middle part of the lower end face of the labyrinth disc sleeve 3 is provided with an annular groove with the depth of 3-5 mm, and the throttle orifice plate 19 is embedded into the annular groove of the labyrinth disc sleeve 3; this results in a coupling fit between the labyrinth disk sleeve 3 and the upper end face of the valve seat 2.
The valve rod 13 penetrates through the central through hole of the valve cover 7, the lower end of the valve rod 13 penetrates through the central through hole of the valve cover 7, the rear end part of the valve rod 13 is hinged with a cylindrical valve core 18, and the upper end of the valve rod 13 penetrates through the central through hole of the valve cover 7 and then is connected with a valve rod position regulator 21.
As shown in fig. 3, a plurality of layers of labyrinth discs 24 are arranged in the middle cylinder of the labyrinth disc sleeve 3 from bottom to top, a plurality of S-shaped horizontal labyrinth flow passages which are radially communicated are formed in the labyrinth discs 24, the plurality of S-shaped horizontal labyrinth flow passages are arranged at intervals along the circumference, and each S-shaped horizontal labyrinth flow passage is radially communicated with the inside and the outside of the labyrinth disc sleeve 3, so that the labyrinth flow passages are arranged in the labyrinth discs to form a labyrinth structure.
As shown in fig. 4, the S-shaped horizontal labyrinth flow channel is a flow channel bent at a right angle, and is divided into a plurality of sub-flow channels according to a radial flow direction, each sub-flow channel is a continuous radial flow section, a cross section is taken at the middle part of each sub-flow channel, a plurality of pressure strain gauges and a plurality of flowmeters are installed on the inner wall of the cross section along the circumference, pressure values of each grid node can be obtained through conversion of the pressure strain gauges, speed values of each grid node can be obtained through conversion of a plurality of installed flowmeters, and it should be noted that the installation position of the flowmeter slightly protrudes from the wall surface.
As shown in fig. 3, it is a single-layer labyrinth disk 24 structure of the labyrinth disk sleeve 3. The structure is formed by mirroring A, B, C, D, E, F along the central direction to have 6 labyrinth flow passages. Taking the flow channel a as an example, the flow channel a includes two inlets and one outlet, the high pressure fluid flows in through the two flow channel inlets and finally flows out from the central hole of the labyrinth plate 24, and in the flow channel with multiple changes of structure, the high pressure fluid is subjected to energy dissipation, and finally the pressure reduction process is completed. Each labyrinth disk sleeve comprises a structure of stacking a plurality of single-layer labyrinth disks in a laminated manner, the structures of the single-layer labyrinth disks are the same, and the positions of labyrinth disk runners of different layers are completely overlapped from a top view, but the runners of each layer are not communicated with each other, so that the multi-runner labyrinth disk sleeve with the multi-layer labyrinth disks connected in parallel is formed.
Fig. 4 is a partially enlarged view of the labyrinth disk flow channel a in fig. 3. For the convenience of subsequent analysis, any one flow channel installed on the labyrinth disk is selected for measurement test. Taking fig. 4 as an example, seven longitudinal sections, namely a section (i), a section (ii), a section (iii), a section (iv), a section (c), and a section (c), are formed in the middle area of the horizontal flow channel. Some longitudinal sections can be arranged according to actual needs, and the more the longitudinal sections are, the more accurate the flow characteristics in the flow channel obtained by testing is, but the cost is increased; if the flow characteristic information of the central area of the cross section is further known, the filament wires which are staggered transversely and longitudinally can be arranged on the rectangular cross section inside the cross section, and the pressure strain gauge and the flowmeter are arranged at the transverse and longitudinal intersection points of the filament wires.
The valve rod 13 is driven by the valve rod position regulator 21 to move up and down, different positions of the valve rod 13 are regulated, and the valve core 18 is further driven to cover different layers of labyrinth discs 24 in the labyrinth disc sleeve 3 to block the circulation of the S-shaped horizontal labyrinth flow passage, so that the opening of the labyrinth disc pressure reducing valve is regulated and controlled.
One or more supporting radial plates 20 are arranged in the center of the interior of the valve core 18, so that the rigidity of the valve core 18 is improved on the basis of ensuring the strength, and the hollow structure in the valve core 18 still has good rigidity.
As shown in fig. 2, a circumferential groove is formed around the outer circle of the middle upper portion of the valve core 18, and an annular graphite strip 25 is embedded in the circumferential groove. The purpose of embedding the annular graphite strip 25 is to keep sealing on one hand, and on the other hand, in view of the self-lubricating function of the graphite strip, the valve rod 13 can drive the valve core 18 to move freely up and down under the action of the valve rod position regulator 21 under the action of high pressure difference, but the vertical distance between the graphite strip 25 and the bottom of the valve core 18 is required to be 20-30 mm higher than the height of the labyrinth disc at the lower part of the labyrinth disc sleeve 3; meanwhile, an annular groove is formed in the outer side area of the lower portion of the valve core and below the graphite strips, so that the valve core 18 and the labyrinth disc sleeve 3 are prevented from being clamped due to unbalanced pressure.
An annular sealing gasket 4 and an annular pressing ring 5 are arranged in an annular gap between the periphery of the valve cover 7 and the circular opening of the valve body 1 from bottom to top, a flange plate 14 is sleeved outside the valve cover 7 above the annular pressing ring 5, the flange plate 14 is fixedly connected with the outer end face of the circular opening of the valve body 1 through a valve cover flange 6 and forms a connection fit with the annular end face of the upper part of the valve body 1, and the annular sealing gasket 4 and the annular pressing ring 5 are tightly pressed in the annular gap. Specifically, the bottom of the annular gap is embedded with an annular sealing gasket 4 to form a first seal, and an annular pressing ring 5 is embedded in the annular gap above the annular sealing gasket 4 to form a second seal.
An annular packing bottom pad 12, a sealing packing 11, a packing gland 8 and a dust ring 10 are embedded into an annular gap between the periphery of a valve rod 13 and a central through hole of a valve cover 7 from bottom to top, a valve cover flange 9 is sleeved outside the valve rod 13 above the dust ring 10, and the valve cover flange 9 is fixedly connected with the outer end face of the central through hole of the valve cover 13 through a locking nut.
As shown in fig. 2, an annular retaining ring 15, an annular retaining ring 16 and a balance seal ring 17 are sequentially arranged in an annular gap between the periphery of the top of a valve core 18 of the valve rod 13 and a central through hole of the labyrinth disc sleeve 3 from top to bottom, the relative positions of the valve core 18 and the labyrinth disc sleeve 3 are determined by the annular retaining ring 15, the annular retaining ring 16 and the balance seal ring 17, and the shaft hole is kept centered.
The testing and controlling process of the internal pressure reduction flow characteristic of the labyrinth disc pressure reducing valve of the embodiment of the invention is as follows:
1) building a circulating pipeline loop, arranging a test valve pipe section in the middle area of the circulating pipeline loop, installing a labyrinth disc pressure reducing valve in the test valve pipe section, wherein the labyrinth disc pressure reducing valve is provided with a labyrinth disc sleeve 3, and flushing and pressurizing the circulating pipeline loop by using a circulating pump and a pressurizing pump to ensure that the inlet pressure of the labyrinth disc pressure reducing valve is between 10.7MPa and 14.7 MPa;
2) for a single-layer labyrinth disc arranged in a labyrinth disc sleeve 3, the single-layer labyrinth disc is divided into a plurality of sub-flow passages according to the radial flow direction, each section is a continuous section which flows in the radial direction, the middle part of each section of the sub-flow passages is provided with a longitudinal section which is specifically a section I, a section II, a section III, a section IV, a section V, a section IV and a section V, n pressure strain gauges and m flow meters are respectively arranged on the inner wall of the flow passage along the longitudinal sections of the plurality of sub-flow passages, and the flow meters are converted to obtain the flow velocity after detecting the flow;
3) flushing the whole circulating pipeline loop by using a circulating pump, and ensuring that the inlet pressure of the labyrinth disc pressure reducing valve is 10.7MPa through a pressurizing pump and a flow control valve at the downstream of the labyrinth disc pressure reducing valve;
4) in the test process, n pressure strain gauges and m flowmeters which are arranged on the inner wall (but not limited to the inner wall) of the flow channel are used for acquiring, analyzing and converting n pressure values and m flow velocity values of the inner wall of the flow channel in real time, and then the harmonic average values of the pressure values and the flow velocity values at different longitudinal sections are calculated:
Wherein N represents the total number of pressure strain gauges/flowmeters, XNRepresenting Nth pressure strain gage/flowmeter acquisitionThe pressure value/flow rate value of (a),
representing the harmonic mean value of the pressure values/flow velocity values collected by all the N pressure strain gauges/flowmeters;
5) repeating the step 3), stepping and increasing the inlet pressure of the labyrinth disc pressure reducing valve for multiple times until the inlet pressure reaches 14.7MPa, then obtaining n pressure values, m flow velocity values and harmonic mean values thereof again by utilizing the step 4), and respectively drawing discrete curves of the harmonic mean values at different sections along with the change of the inlet pressure of the labyrinth disc pressure reducing valve;
for the same section, the maximum value of the pressure values or the flow velocity values of different measuring points at the section can be obtained through calculation and analysis, and a mean value curve can be drawn through calculating the harmonic mean value of the pressure values or the flow velocity values.
As shown in fig. 5 and 7, the maximum pressure value distribution map and the maximum velocity value distribution map of different longitudinal sections are shown, respectively. Namely, the maximum pressure value distribution and the maximum flow velocity value distribution of different cross section positions drawn in the step 5) are adopted. As shown in fig. 6 and 8, the pressure value (harmonic mean value) distribution diagram and the velocity value (harmonic mean value) distribution diagram of different longitudinal sections are shown.
The solution formula based on the turbulence energy is as follows:
in the formula: re represents a Reynolds number;
the combination of the above steps can calculate the distribution graph of the maximum value of the turbulence kinetic energy of different longitudinal sections (FIG. 9) and the distribution graph of the value of the turbulence kinetic energy of different longitudinal sections (harmonic mean value) (FIG. 10).
6) For different sections of the labyrinth disc pressure reducing valve, calculating energy dissipation values of adjacent sections by using the following formula to obtain energy dissipation performance, and drawing energy dissipation maps corresponding to inlet pressures of different discrete labyrinth disc pressure reducing valves:
in the formula: epsilon is an energy dissipation value, rho is the density of the water phase, g is the acceleration of gravity,
the harmonic mean value of the pressure value of each measuring point on the J-th section is shown,
represents the harmonic mean of all m flow velocity values on the jth section,
represents the harmonic mean of all n pressure values on the J-th section;
FIG. 11 is a graph of the energy dissipation in the labyrinth flow path calculated using the above equation for a corresponding inlet pressure of 10.7 MPa.
7) According to the energy dissipation maps corresponding to the inlet pressures of the different discrete labyrinth disc pressure reducing valves established in the step 6), the energy dissipation maps corresponding to the inlet pressures of the continuous labyrinth disc pressure reducing valves are calculated in an interpolation mode, and the critical energy dissipation value [ epsilon ] of a cavitation erosion/erosion damage point of a flow channel in the labyrinth disc sleeve 3 under different working conditions is determined through the regular anatomical analysis of the labyrinth discs in the pressure reducing valves;
8) the valve rod position regulator 21 is used for regulating and controlling the positions of different valve rods 13 so as to regulate the opening degree of the labyrinth disc pressure reducing valve, so that the layer number adjustment of labyrinth discs 24 in the labyrinth disc sleeve 3 is realized, the layer number of different labyrinth discs in the labyrinth disc sleeve 3 and energy dissipation maps in corresponding labyrinth disc runners under the inlet pressure of different labyrinth disc pressure reducing valves are tested, and a map library of a critical energy dissipation value [ epsilon ] is established;
9) in the dynamic testing process, dynamically monitoring the pressure value of a pressure strain gauge in a labyrinth flow channel and the flow rate value of a flowmeter to obtain a real-time energy dissipation value epsilon, and comparing the real-time energy dissipation value epsilon with a critical energy dissipation value [ epsilon ]:
if epsilon < [ epsilon ], the valve rod position regulator 21 keeps unchanged;
if epsilon is more than or equal to epsilon, the valve rod position regulator 21 regulates the opening increasing degree and updates and reprocesses the energy dissipation value epsilon until epsilon < [ epsilon ].
The specific implementation can obtain the internal pressure reduction flowing state of the current labyrinth disc pressure reducing valve by comparing the actually obtained pressure value and flow velocity value according to the energy dissipation map.
Claims (9)
1. A metering test and control method for the internal pressure reduction flow characteristic of a labyrinth disk pressure reducing valve is characterized in that: the method comprises the following testing and control steps:
1) building a circulating pipeline loop, arranging a test valve pipe section in the middle area of the circulating pipeline loop, installing a labyrinth disc pressure reducing valve in the test valve pipe section, flushing and pressurizing the circulating pipeline loop by using a circulating pump and a pressurizing pump, and ensuring that the inlet pressure of the labyrinth disc pressure reducing valve is between 10.7MPa and 14.7 MPa;
2) for the device arranged on the labyrinth disc sleeve (3), the device is divided into a plurality of sub-flow channels according to the radial flow direction, the middle part of each sub-flow channel is provided with a cross section, and n pressure strain gauges and m flow meters are respectively arranged on the inner wall of the flow channel where the longitudinal cross sections of the plurality of sub-flow channels are located;
3) flushing the whole circulating pipeline loop by using a circulating pump, and ensuring that the inlet pressure of the labyrinth disc pressure reducing valve is 10.7MPa through a pressurizing pump and a flow control valve at the downstream of the labyrinth disc pressure reducing valve;
4) in the test process, the n pressure strain gauges and the m flow meters which are arranged on the inner wall of the flow channel are utilized to acquire, analyze and convert in real time to obtain n pressure values and m flow velocity values of the inner wall of the flow channel, and then the harmonic average values of the pressure values and the flow velocity values at the section are respectively calculated:
wherein N represents the total number of pressure strain gauges/flowmeters, XNIndicating Nth pressure strain gage/flowThe pressure value/flow velocity value acquired by the meter and obtained by conversion,
representing the harmonic mean value of the pressure values/flow velocity values collected by all the N pressure strain gauges/flowmeters;
5) repeating the step 3), stepping and increasing the inlet pressure of the labyrinth disc pressure reducing valve for multiple times until the inlet pressure reaches 14.7MPa, then obtaining n pressure values, m flow velocity values and harmonic mean values thereof again by utilizing the step 4), and respectively drawing discrete curves of the harmonic mean values at different sections along with the change of the inlet pressure of the labyrinth disc pressure reducing valve;
6) for different sections of the labyrinth disc pressure reducing valve, calculating energy dissipation values of adjacent sections by using the following formula, and drawing energy dissipation maps corresponding to inlet pressures of different discrete labyrinth disc pressure reducing valves:
in the formula: epsilon is an energy dissipation value, rho is the density of the water phase, g is the acceleration of gravity,
the harmonic mean value of the pressure value of each measuring point on the J-th section is shown,
represents the harmonic mean of all m flow velocity values on the jth section,
represents the harmonic mean of all n pressure values on the J-th section;
7) according to the energy dissipation maps corresponding to the inlet pressures of the different discrete labyrinth disc pressure reducing valves established in the step 6), the energy dissipation maps corresponding to the inlet pressures of the continuous labyrinth disc pressure reducing valves are calculated in an interpolation mode, and the critical energy dissipation value [ epsilon ] of a cavitation erosion or erosion damage point of a flow channel in the labyrinth disc sleeve (3) is determined;
8) the positions of different valve rods (13) are adjusted and controlled by using a valve rod position adjusting and controlling device (21) so as to adjust the opening degree of the labyrinth disc pressure reducing valve, the layer number of labyrinth discs (24) in the labyrinth disc sleeve (3) is adjusted, and the layer number of the different labyrinth discs in the labyrinth disc sleeve (3) and an energy dissipation map in corresponding labyrinth disc runners under the inlet pressure of the different labyrinth disc pressure reducing valves are tested;
9) in the dynamic testing process, dynamically monitoring a pressure value converted by a pressure strain gauge in a labyrinth flow channel and a flow rate value converted by a flowmeter, obtaining a real-time energy dissipation value epsilon and comparing the energy dissipation value epsilon with a critical energy dissipation value [ epsilon ]:
if epsilon < -epsilon >, the valve rod position regulator (21) keeps unchanged;
if epsilon is more than or equal to epsilon, the valve rod position regulator (21) regulates the opening increasing degree and updates and reprocesses the energy dissipation value epsilon until epsilon < [ epsilon ].
2. The method of claim 1, wherein the step-down flow characteristic of the labyrinth disk pressure reducing valve is measured and controlled by the following steps:
the labyrinth disc pressure reducing valve comprises a valve body (1), a valve seat (2), a labyrinth disc sleeve (3), a valve cover (7), a valve rod (13), a valve core (18), a throttling orifice plate (19) and a valve rod position regulator (21); the top of the valve body (1) is provided with a circular opening, a valve cover (7) is installed in the circular opening, a central through hole is formed in the valve cover (7) in the vertical direction, an upper cavity and a lower cavity are formed in the valve body, the end parts of the two sides of the valve body are provided with a horizontal medium inlet (22) and a horizontal medium outlet (23), the medium inlet (22) is communicated with the upper cavity of the valve body (1), and the medium outlet (23) is communicated with the lower cavity of the valve body (1); the upper cavity and the lower cavity are connected through a through hole, a valve seat (2) is arranged at the through hole, a labyrinth disc sleeve (3) is arranged on the valve seat, and the lower part of the valve cover (7) is in interference fit with the upper part of the labyrinth disc sleeve (3);
the valve cover (7) and the labyrinth disc sleeve (3) are both provided with central through holes, and the valve cover (7) and the central through holes of the labyrinth disc sleeve (3) are coaxially and vertically communicated; the valve seat (2) is mainly coaxially formed by an upper cylinder and a lower cylinder, the diameter of the upper cylinder is larger than that of the lower cylinder, an inverted cone inner cavity is formed in the center of the upper cylinder, a cylindrical inner cavity is formed in the lower cylinder, a throttling pore plate (19) provided with a vertical throttling hole is arranged on the top end face of the inverted cone inner cavity, the inverted cone inner cavity is communicated with the bottom of a central through hole of the labyrinth disc sleeve (3) through the throttling pore plate (19), the inverted cone inner cavity is communicated with the cylindrical inner cavity, pore plates provided with horizontal partition throttling holes are uniformly distributed between the inverted cone inner cavity and the cylindrical inner cavity, a plurality of fluid outlet holes are uniformly distributed on the bottom end face of the cylindrical inner cavity, and the fluid outlet holes and the horizontal partition throttling holes are arranged in a staggered mode; an annular groove is formed in the edge of the top surface of a cylinder at the upper part of the valve seat (2), an annular boss is arranged on the edge of the lower end face of the labyrinth disc sleeve (3), and the annular boss of the labyrinth disc sleeve (3) is embedded into the annular groove of the valve seat (2) to form connection matching; the middle part of the lower end surface of the labyrinth disc sleeve (3) is provided with an annular groove, and the throttle orifice plate (19) is embedded into the annular groove of the labyrinth disc sleeve (3); the valve rod (13) penetrates through a central through hole of the valve cover (7), the lower end of the valve rod (13) penetrates through the central through hole of the valve cover (7), the rear end part of the valve rod (13) is hinged with a cylindrical valve core (18), and the upper end of the valve rod (13) penetrates through the central through hole of the valve cover (7) and then is connected with a valve rod position regulator (21).
3. The method of claim 2, wherein the step-down flow characteristic of the labyrinth disk pressure reducing valve is measured and controlled by the following steps: a plurality of layers of labyrinth discs (24) are distributed in the middle barrel of the labyrinth disc sleeve (3) from bottom to top, and a plurality of S-shaped horizontal labyrinth flow channels which are communicated in the radial direction are formed in the labyrinth discs (24).
4. The method of claim 3, wherein the step-down flow characteristic of the labyrinth disk pressure reducing valve is measured and controlled by the following steps: the S-shaped horizontal labyrinth flow channel is a flow channel bent at a right angle and is divided into a plurality of sections of sub-flow channels according to the radial flow direction, the middle part of each section of sub-flow channel is provided with a cross section, and the inner wall of the cross section is provided with a plurality of pressure strain gauges and a plurality of flow meters along the circumference.
5. The method of claim 2, wherein the step-down flow characteristic of the labyrinth disk pressure reducing valve is measured and controlled by the following steps: the lower end of the valve cover (7) is provided with an annular concave hole, the upper part of the labyrinth disc sleeve (3) is provided with an annular boss, and the annular boss is sleeved in the annular concave hole to form interference fit.
6. The method of claim 2, wherein the step-down flow characteristic of the labyrinth disk pressure reducing valve is measured and controlled by the following steps: the valve core (18) is internally provided with one or more supporting radial plates (20) in the center, a circumferential groove is formed around the excircle of the middle upper part of the valve core (18), and an annular graphite strip (25) is embedded in the circumferential groove.
7. The method of claim 2, wherein the step-down flow characteristic of the labyrinth disk pressure reducing valve is measured and controlled by the following steps: valve gap (7) periphery and valve body (1) circular opening between the annular clearance in from the bottom up be equipped with annular seal gasket (4) and annular clamping ring (5), valve gap (7) overcoat ring flange (14) of annular clamping ring (5) top, ring flange (14) are connected fixedly through valve gap flange (6) and valve body (1) circular opening's outer terminal surface, compress tightly annular seal gasket (4) and annular clamping ring (5) in the annular clearance, constitute sealedly.
8. The method of claim 2, wherein the step-down flow characteristic of the labyrinth disk pressure reducing valve is measured and controlled by the following steps: the valve is characterized in that an annular packing bottom pad (12), a sealing packing (11), a packing gland (8) and a dust ring (10) are embedded into an annular gap between the periphery of the valve rod (13) and a central through hole of the valve cover (7) from bottom to top, a valve rod flange (9) is sleeved outside the valve rod (13) above the dust ring (10), and the valve rod flange (9) is fixedly connected with the outer end face of the central through hole of the valve cover (7) through a locking nut.
9. The method of claim 2, wherein the step-down flow characteristic of the labyrinth disk pressure reducing valve is measured and controlled by the following steps: an annular retaining ring (15), an annular retaining ring (16) and a balance sealing ring (17) are sequentially arranged in an annular gap between the periphery of the top of a valve core (18) connected with a valve rod (13) and a central through hole of the labyrinth disc sleeve (3) from top to bottom.
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| CN114576380B (en) * | 2022-03-15 | 2023-07-04 | 长春电子科技学院 | Sampling valve with labyrinth damping structure |
| CN116624652B (en) * | 2023-07-25 | 2023-09-29 | 哈电集团哈尔滨电站阀门有限公司 | Disc design method and labyrinth control valve |
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