CN107479585A - The critical flow venturi for principle of being jammed based on machinery - Google Patents
The critical flow venturi for principle of being jammed based on machinery Download PDFInfo
- Publication number
- CN107479585A CN107479585A CN201710641683.2A CN201710641683A CN107479585A CN 107479585 A CN107479585 A CN 107479585A CN 201710641683 A CN201710641683 A CN 201710641683A CN 107479585 A CN107479585 A CN 107479585A
- Authority
- CN
- China
- Prior art keywords
- mrow
- float
- orifice plate
- venturi
- guide rod
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D7/00—Control of flow
- G05D7/03—Control of flow with auxiliary non-electric power
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Jet Pumps And Other Pumps (AREA)
Abstract
The invention discloses a kind of venturi nozzle body for being jammed the critical flow venturi of principle based on machinery, including pantographic, the venturi nozzle body is made up of the head contraction section, throat's straight length and afterbody diffuser being linked in sequence；The entrance point that the venturi nozzle body is located at head contraction section is provided with upstream installation orifice plate, and the port of export that the venturi nozzle body is located at afterbody diffuser is provided with downstream installation orifice plate；The inner chamber of the venturi nozzle body is equipped with guide rod, and the central axis of the guide rod overlaps with the central axis of venturi nozzle body；It is arranged with the guide rod and is used to controlling the float of fluid flow across throat's straight length, the float can slides axially along guide rod under the driving of fluid and the circulation passage of variable area is formed with throat straight length.The present invention can realize the critical flow of incompressible fluid under compared with low flow velocity and less drag losses, and can shield influence of the upstream and downstream pressure disturbance to flow simultaneously.
Description
Technical field
The present invention relates to fluid control and field of measuring technique, and in particular to a kind of critical flow for principle of being jammed based on machinery
Venturi nozzle.
Background technology
Critical flow is widely used in scientific research and engineering technology.Under certain intake condition, when downstream pressure reaches
During to a certain critical value, a maximum can be reached by flowing through the mass flow of throttling arrangement, if further reducing downstream pressure,
Flow will remain invariable, and flow regime now is referred to as critical flow, also referred to as choked flow.It is special using the flowing of critical flow
Property, it is possible to achieve the accurate control and measurement of flow.
For flowing of the compressible fluid in venturi nozzle, when downstream pressure is reduced to a certain critical value, air-flow
Take the lead in reaching local velocity of sound in the flow velocity of throat, due to the effect of throat's downstream diffuser, fluid slows down supercharging in diffuser,
Balanced each other to outlet and external environment back pressure.Now flow reaches maximum, i.e. critical flow.If continue to reduce downstream
Pressure, shock wave can be formed in a certain section in throat downstream, although the very thin thickness of shock wave, resistance is very big, will can swash
Wave surface regards a barrier layer being made up of dense gas as, can produce a kind of extra " additional drag " during airflow passes, disappear
Substantial amounts of kinetic energy is consumed, and is somebody's turn to do " additional drag " size of value can be automatically adjusted, maintains critical flow constant.For example, instantly
When swimming pressure reduces, inlet outlet pressure differential becomes big, and flow has the trend for becoming big, but the now downward downstream of shock wave, shock strength
Enhancing, now the thickness of shock wave can be thinning, but more fine and close, and therefore " wave resistance " becomes big, i.e., additional drag becomes big, just
The reduction of downstream pressure is compensate for, prevents the increase of flow, maintains flow constant.Equally, when downstream pressure raises, disengaging
Mouth pressure difference reduces, and flow has the trend to diminish, and now shock wave moves to the position of trip on the upper side, the free stream Mach number before shock front
Reduce, shock strength reduces, and the thickness of shock wave can be thickening, and can become relative matter and dredge, and additional drag when fluid flows through subtracts
It is small, prevent flow from reducing, make its holding invariable.
For flowing of the compressible fluid in venturi nozzle, when downstream pressure is reduced to a certain critical value, fluid
It can be begun to boil off at the position of throat or throat downstream because pressure reaches saturated vapor pressure.When vaporizing generation, aditus laryngis is attached
The quick local phase transformation by liquid to gas will closely occur, although the now quality share very little of steam, its volume is but
It is very big, flow resistance can be caused to rise sharply.Therefore cavitation area is that a resistance being made up of bubble is very big " air pocket barrier layer ",
Fluid by when can produce a kind of extra additional drag.If downstream pressure continues to reduce, flow has the trend for becoming big, still
Cavitation intensity now will also increase therewith, cause the expansion and elongation on " air pocket barrier layer ", and fluid flows through the additional of cavitation area
Resistance will increase, and thus compensate for downstream pressure reduces influence to flow so that when fluid flow to outlet with it is extraneous
Environment back pressure balances each other, and maintains the constant of flow.Similarly, if downstream pressure increases, cavitation intensity reduces therewith, causes
The contraction on air pocket barrier layer reduces, and reduces additional drag when fluid flows through the region, prevents flow from reducing, and maintains flow permanent
It is fixed.
But this critical flow venturi structure being jammed based on cavitation, it is mainly used in liquid-fuel rocket hair
In motivation, and in Other Engineering field using less.Limit its wide variety of subject matter and following several respects be present：
(1) the same with other cavitation phenomenonses, when occurring cavitation inside Venturi tube, the gas core in liquid can be in low-pressure area
Rapid expansion formation is evident that bubble, and can crumble and fall when bubble flows through higher-pressure region, gives off energy, when shorter
Between and less volume in reach high-energy-density state, form Local Phase to HTHP area, can also produce strong shock wave
And high-speed micro-jet, strong corrosion function can be produced to most of fluid devices or tube wall, while also can be with huge
Noise and judder, cause potential safety hazard.This just proposes the requirement of harshness to device materials and service condition.Due to liquid
The working time of rocket engine is very short, plus the material using high rigidity, cavitation for it not one it is serious
Problem, in other field, because such condition of work is difficult to meet, but fail always although also having and contemplating well
To good application.
(2) pressure drop of cavitation venturi nozzle and drag losses are very big.Such as saturated vapor pressure of the water at 25 DEG C is only
There is 3.17kPa, almost can be ignored compared with import pressure, it means that the static energy of upstream will be totally converted in throat
Critical stream mode is can be only achieved into kinetic energy.For venturi nozzle, there is the pressure close to upstream stagnation pressure 20% will be permanent
Property loses, and this will cause huge energy dissipation.For example, in water injection well in oil fields, average water injection pressure is 30MPa left
The right side, to use cavitation venturi nozzle in tubing string is distributed, minimum drag losses reaches 6MPa, and this loss is much larger than in general
Resistance piece, it is that common engineering is difficult to receive.
(3) (such as entrance Fluid pressure is relatively low, or fluid temperature (F.T.) is higher in the case of relatively low import degree of supercooling
Situation), especially for low discharge, the cavitation venturi nozzle of reduced size, due to fluid venturi nozzle throat very
Easily there is superheat state, i.e., it is uneven there is thermodynamics, it may appear that " excessively stream " phenomenon, to cause flow to be more than theoretical calculation
Maximum stream flow, it have impact on the precision of flow control.For the fluid of low import degree of supercooling, even if back pressure is less than critical pressure
By force, " critical flow " and " excessively stream " two states are still there may be, flow can not uniquely determine, and so allow for flow control
During there is larger deviation.
(4) because cavitation phenomenons is a quasi-steady state process, pressure oscillation meeting caused by the generation and rupture of cavitation area bubble
Cause flow also to fluctuate therewith, influence the precision of flow control.Simultaneously as the liquid filling around being needed during bubbles burst is empty
Cave, therefore flow can also fluctuate with the change of cavitation area form.Result of study shows that cavitation venturi nozzle is being jammed
Flow control error during state is all 10% or so, even more high.
In summary, due to the incompressible fluid critical flow venturi that is jammed based on cavitation there is flow velocity it is high,
Drag losses is big, flow control is unstable, requires the defects of high to the strength of materials, is limited in the application by more.
The content of the invention
Present invention aims to overcome that the deficiency of above-mentioned background technology, and provide a kind of based on mechanical the critical of principle of being jammed
Venturi nozzle is flowed, the critical flow of incompressible fluid, and energy can be realized under compared with low flow velocity and less drag losses
It is enough to shield influence of the upstream and downstream pressure disturbance to flow simultaneously.
To achieve the above object, the critical flow venturi of a kind of principle of being jammed based on machinery provided by the present invention,
Venturi nozzle body including pantographic, the venturi nozzle body is by the head contraction section, the throat's straight tube that are linked in sequence
Section and afterbody diffuser composition；The entrance point that the venturi nozzle body is located at head contraction section is provided with upstream installation
Orifice plate, the port of export that the venturi nozzle body is located at afterbody diffuser are provided with downstream installation orifice plate；The venturi spray
The inner chamber of tube body is equipped with guide rod, and the central axis of the guide rod overlaps with the central axis of venturi nozzle body；Institute
The one end for stating guide rod is threadedly coupled with the centre bore of upstream installation orifice plate, and the other end and the downstream of the guide rod are installed in orifice plate
Heart hole is threadedly coupled；
It is arranged with the guide rod across float of throat's straight length for controlling fluid flow, and the both ends difference of float
Orifice plate is upstream installed, downstream installation orifice plate extends to form streamlined structure；The float installs one end of orifice plate towards upstream
For free end, the float is installed orifice plate with downstream by the spring being set on guide rod towards one end of downstream installation orifice plate and connected
Connect, the float can slide axially along guide rod under the driving of fluid and the circulation passage of variable area is formed with throat straight length.
In above-mentioned technical proposal, the upstream installation orifice plate is identical with the structure of downstream installation orifice plate, the upstream installation
The middle part that orifice plate includes outer shroud, is arranged on outer shroud has the outer of the inner ring of centre bore and the inwall for being arranged on outer shroud and inner ring
Pole composition between wall；The quantity of the pole is three, and is arranged along the inwall circumference uniform intervals of outer shroud, adjacent two
The sector channel to circulate for liquid is left between pole.The both ends of the guide rod are provided with external screw thread, the center of the inner ring
Hole inwall is provided with the internal thread to match with external screw thread.
In above-mentioned technical proposal, the float is by the float first section, effective control section and float endpiece group that are linked in sequence
Into the float first section is arranged towards upstream installation orifice plate arrangement, the float endpiece towards downstream installation orifice plate, the float
Central axis overlapped with the central axis of venturi nozzle body.
In above-mentioned technical proposal, the shape line equation of the profile bus of effective control section of the float along its axial direction by
Following formula determines：
In formula：X, y are respectively abscissa and ordinate corresponding to arbitrfary point on profile bus, and Q is critical mass flow rate, θ
For the characteristic coefficient that is jammed, R is the radius of throat's straight length, and ρ is fluid density, and k is the coefficient of elasticity of spring, and b is the pre- of spring
Decrement, r are the radius of guide rod, and L is the length of effective control section.
In above-mentioned technical proposal, the characteristic coefficient θ that is jammed is relevant with structural parameters and flow parameter, and it embodies shape
Formula θ=θ (x) determines the characteristic coefficient θ that is jammed using CFD method for numerical simulation, comprises the following steps that：
1) θ=1 is assumed；
2) according to the θ values in step 1), the shape line equation y=f (x) of float is calculated；
3) structure of float is determined according to the shape line equation obtained in step 2) step, and establishes and is jammed accordingly based on machinery
The mathematical calculation model of the critical flow venturi of principle, then obtained using Fluent softwares in different import and export pressures
The corresponding discharge Q of the jet pipe is flowed through under differencenum；
If 4)Using the numerical simulation result in step 3) step, float is calculated in different positions
θ values under moving, the expression-form θ=θ (x) new characteristic coefficient θ that is jammed is fitted, and is replaced with the new expression formula in step 1)
θ values, then repeat step 2) and step 3)；
5) whenWhen, iterative program terminates, set by obtained float shape line equation y=f (x) satisfactions
The critical flow requirement of meter.
In above-mentioned technical proposal, the length L of the effectively control section is according to maximum allowable operting differential pressure Δ PmaxPass through following formula
To determine,
In formula：R is the radius of throat's straight length, and r is the radius of guide rod, and Q is critical mass flow rate, and θ is characteristic system of being jammed
Number, ρ are fluid density, and k is the coefficient of elasticity of spring, Δ PmaxDuring for cavitation does not occur in venturi nozzle body import and export it
Between maximum differential pressure.
In above-mentioned technical proposal, the range of the float is less than or equal to L.
Compared with prior art, there is following advantage in the present invention：
The present invention is using setting a spring-floating molecular mechanical component in the aperture of Venturi tube as " being jammed
Body ", it should form " be jammed body " and " shock wave wave resistance " or " air pocket barrier layer " similar " additional drag part ", the flowing of convection body
A kind of additional drag is formd, and it can also occur mechanical movement automatically with the change of downstream pressure and adjust the additional resistance
The size of power, accurately block from influence of the downstream parameter fluctuation to flow, it is constant finally to maintain flow.This new base
In the critical flow venturi structure that machinery is jammed, neither require that flow velocity reaches velocity of sound, it is not required that liquid reduces pressure hair
Raw cavitation, that is, allow fluid under the operating mode of " subcritical " flowing, realizes the function of " critical flow ", thus has that flow velocity is low, resistance
Small, noiseless, vibrationless feature is lost, is a kind of effectively practical method for solving the critical flow problem of incompressible fluid.
Embodiment
Fig. 1 is the structural representation of critical flow venturi of the present invention based on mechanical principle of being jammed.
Fig. 2 is Floater Structure schematic diagram in Fig. 1.
Fig. 3 is the cross section structure diagram that Fig. 1 middle and upper reaches install orifice plate.
Fig. 4 is the side structure schematic view that Fig. 1 middle and upper reaches install orifice plate.
Fig. 5 is the Optimizing Flow schematic diagram figure of the effective control section shape line of float.
In figure：1- venturi nozzles body, 1.1- heads contraction section, 1.2- throats straight length, 1.3- afterbodys diffuser, 2-
Upstream installation orifice plate, 2.1- outer shrouds, 2.2- inner ring, 2.3- poles, 3- downstreams installation orifice plate, 4- guide rods, 5- floats, 5.1- floats
The effective control section of first section, 5.2-, 5.3- floats endpiece, 6- springs.
Embodiment
Describe the performance of the present invention in detail with reference to embodiment, but they do not form limitation of the invention,
It is only for example.Simultaneously by illustrating that advantages of the present invention will become clearer and be readily appreciated that.
A kind of critical flow venturi of principle of being jammed based on machinery as shown in Figure 1, include the venturi of pantographic
Spout body 1, the venturi nozzle body 1 is by the head contraction section 1.1, throat's straight length 1.2 and afterbody that are linked in sequence
Diffuser 1.3 forms；The entrance point that the venturi nozzle body 1 is located at head contraction section 1.1 is provided with upstream installation orifice plate
2, the port of export that the venturi nozzle body 1 is located at afterbody diffuser 1.3 is provided with downstream installation orifice plate 3；The venturi
The inner chamber of spout body 1 is equipped with guide rod 4, and the central axis weight of the central axis of the guide rod 4 and venturi nozzle body 1
Close；One end of the guide rod 4 is threadedly coupled with the centre bore of upstream installation orifice plate 2, and the other end and the downstream of the guide rod 4 are installed
The centre bore threaded connection of orifice plate 3；
It is arranged with the guide rod 4 across float 5 of the throat's straight length 1.2 for controlling fluid flow, and the two of float 5
Orifice plate 2 is upstream installed at end respectively, the installation extension of orifice plate 3 in downstream forms streamlined structure, central axis and the guide rod 4 of float 5
Central axis overlap.The float 5 is free end towards one end of upstream installation orifice plate 2, and the float 5 is installed towards downstream
One end of orifice plate 3 is installed orifice plate 3 with downstream by the spring 6 being set on guide rod 4 and is connected, and the float 5 can be in the drive of fluid
Slid axially under dynamic along guide rod 4 and the circulation passage of variable area is formed with throat straight length 1.2.When float 5 is located at initial position,
Spring 6 has certain pre compressed magnitude, therefore spring 6 remains compressive state.Float 5 with special form line is across text
Throat's straight length 1.2 of spout body 1 in mound, and one is constituted between throat's straight length 1.2 of venturi nozzle body 1
The annular flow passage of variable area.The minimum flow area of critical flow venturi based on mechanical principle of being jammed, which is equal to, to be cut
Nose cone ABCD lateral area, the size of its area change with the movement of float 5.The situation of movement of float 5 is according to fluid
Both elastic forces of driving force and spring 6 interaction and determine.
As shown in Fig. 2 the float 5 is by the float first section 5.1, effective control section 5.2 and float endpiece that are linked in sequence
5.3 compositions, its geometry design according to fluid mechanics principle, reduce the resistance of flow separation and convection body as far as possible.It is described floating
Sub- first section 5.1 arranges that the float endpiece 5.3 is arranged towards downstream installation orifice plate 3 towards upstream installation orifice plate 2.Its float is first
Section 5.1 can reduce drag losses, improve the stability that float 5 moves, and the setting of float endpiece 5.3 can also improve float
The stability of motion.
In above-mentioned technical proposal, the shape of the profile bus 5.21 of effective control section 5.2 of the float 5 along its axial direction
Line equation is determined by following formula：
In formula：X, y are respectively abscissa and ordinate corresponding to arbitrfary point on profile bus, and Q is critical mass flow rate, θ
For the characteristic coefficient that is jammed, R is the radius of throat's straight length 1.2, and ρ is fluid density, and k is the coefficient of elasticity of spring 6, and b is spring 6
Pre compressed magnitude, r be guide rod 4 radius, L be effective control section 5.2 length.
In above-mentioned technical proposal, the characteristic coefficient θ that is jammed has reacted discharge coefficient and the distribution of device internal pressure to floating
The influence of minor structure, the characteristic coefficient θ that is jammed is relevant with structural parameters and flow parameter, and it embodies form θ=θ (x) needs
Determined by the method for experiment or CFD numerical simulations, the characteristic coefficient θ that is jammed is determined using CFD method for numerical simulation, specifically
Step is as follows：
1) θ=1 is assumed；
2) according to the θ values in step 1), the shape line equation y=f (x) of float is calculated；
3) structure of float is determined according to the shape line equation obtained in step 2) step, and establishes and is jammed accordingly based on machinery
The mathematical calculation model of the critical flow venturi of principle, then obtained using Fluent softwares in different import and export pressures
The corresponding discharge Q of the jet pipe is flowed through under differencenum；
If 4)Using the numerical simulation result in step 3) step, float is calculated in different positions
θ values under moving, the expression-form θ=θ (x) new characteristic coefficient θ that is jammed is fitted, and is replaced with the new expression formula in step 1)
θ values, then repeat step 2) and step 3)；
5) whenWhen, iterative program terminates, set by obtained float shape line equation y=f (x) satisfactions
The critical flow requirement of meter.
In above-mentioned technical proposal, the length L of the effectively control section 5.2 is according to maximum allowable operting differential pressure Δ PmaxPass through
Following formula determines,
In formula：R is the radius of throat's straight length 1.2, and r is the radius of guide rod 4, and Q is critical mass flow rate, and θ is spy of being jammed
Property coefficient, ρ are fluid density, and k is the coefficient of elasticity of spring 6, Δ PmaxTo enter when cavitation not occurring in venturi nozzle body 1,
Maximum differential pressure between outlet.The range of the float 5 is less than or equal to L.
As shown in Figure 3 and Figure 4, the upstream installation orifice plate 2 is identical with the structure of downstream installation orifice plate 3, the upstream peace
Dress orifice plate 2 has the inner ring 2.2 of centre bore and is arranged on outer shroud 2.1 including outer shroud 2.1, the middle part for being arranged on outer shroud 2.1
Pole 2.3 between inwall and the outer wall of inner ring 2.2 forms；The quantity of the pole 2.3 is three, and along outer shroud 2.1
Wall circumference uniform intervals are arranged, the sector channel to circulate for liquid is left between adjacent two poles 2.3.The two of the guide rod 4
End is provided with external screw thread, and the center bore inner wall of the inner ring 2.2 is provided with the internal thread to match with external screw thread.Install upstream
Orifice plate 2 and downstream installation orifice plate 3 can keep float to be located at the center of runner, and the installation site of upstream installation orifice plate 2 will
Ensure float in initial position, interface and the venturi nozzle throat straight length of effective control section 22 and float endpiece 5.3
1.2 upstream face overlaps, and adjusts the relative position between downstream installation orifice plate 3 and guide rod, can adjust the precompressed of spring 6
Contracting amount.
The operation principle of critical flow venturi based on mechanical principle of being jammed is as follows：Float has smooth surface
Rotary body, the approximate cone of its effective control section, and diameter is from upstream to downstream and is gradually reduced.So sprayed in venturi
Install spring-float " be jammed body " in tube body additional, just constitute " air pocket stop in a similar traditional cavitation venturi nozzle
The additional throttling element of layer " equally, it can extend and shrink automatically with the fluctuation of downstream pressure, maintain critical stream mode.Instantly
When swimming pressure reduces, the pressure difference increase at float both ends, the downward downstream of compression spring, what float surrounded with venturi nozzle throat
Annular flow aisle spare reduces, and increases throttle degree, so that additional drag increases, prevents flow from increasing, maintains flow
It is constant.Otherwise when downstream pressure raises, the pressure difference at float both ends reduces, spring elongation, adds the area of circular passage, drop
The low throttle degree of convection body, reduces additional drag, maintains flow constant.Therefore, this spring-float " be jammed body " structure
Into " additional throttling element " can effectively block downstream pressure to disturb influence to flow, realize critical flow.In addition, it is this
The critical flow device formed based on mechanism can also block upstream pressure to disturb the influence to flow.For example, work as upstream pressure
During increase, the pressure difference at float both ends can increase, and drive spring to move downwardly together, reduce circulation area, increase throttle degree
Greatly, so as to which additional drag increase, flow remain unchanged.Equally when upstream pressure reduces, the upward downstream of float, reduce additional
Resistance, prevent flow from increasing, maintain flow constant.
According to analysis above, either compressible fluid or incompressible fluid, the realization of its critical flow be all according to
A kind of automatically adjusting for the additional resistance formed by fluid in flow process itself balances out shadow of the pressure difference change to flow
Ring.Compressible fluid is that the additional drag formed by " shock wave wave resistance " is automatically adjusted to balance the change of downstream back pressure, is maintained
Critical flow；And incompressible fluid is then " dilatation " that " air pocket barrier layer " is formed by bubble, fluid is changed
The size of additional drag when flowing through, to balance out influence of the downstream pressure change to flow, realize critical flow.Although " shock wave ripple
Resistance " or the behavior on " air pocket barrier layer " are extremely complex, but its final effect be exactly produce one can automatically adjust it is additional
Resistance, just as one " additional drag part " installing in the duct, adjustment control the change of flow for they.Inspired by this,
Replace or simulate caused by this " shock wave wave resistance " or " air pocket barrier layer " using spring-float " be jammed body " of the present invention
The effect of convection body " additional drag ", can realize critical flow in the case of easier, it is possible to overcome cavitation venturi to spray
The segmental defect of pipe, improve the application of incompressible fluid critical flow device.
The content that this specification is not described in detail belongs to prior art known to professional and technical personnel in the field.
Claims (8)
1. a kind of critical flow venturi for principle of being jammed based on machinery, include the venturi nozzle body (1) of pantographic, institute
Venturi nozzle body (1) is stated by the head contraction section (1.1), throat's straight length (1.2) and afterbody diffuser that are linked in sequence
(1.3) form, it is characterised in that：
The entrance point that the venturi nozzle body (1) is located at head contraction section (1.1) is provided with upstream installation orifice plate (2), institute
State venturi nozzle body (1) be located at afterbody diffuser (1.3) the port of export be provided with downstream installation orifice plate (3)；The literary mound
In the inner chamber of spout body (1) be equipped with guide rod (4), and the central axis of the guide rod (4) and venturi nozzle body (1)
Central axis overlaps；One end of the guide rod (4) is threadedly coupled with the centre bore of upstream installation orifice plate (2), the guide rod (4)
The other end is threadedly coupled with the centre bore of downstream installation orifice plate (3)；
It is arranged with the guide rod (4) across float (5) of the throat's straight length (1.2) for controlling fluid flow, and float (5)
Both ends respectively upstream install orifice plate (2), downstream installation orifice plate (3) extension form streamlined structure；Float (5) direction
One end of upstream installation orifice plate (2) is free end, and the float (5) is towards one end of downstream installation orifice plate (3) by being set in
Spring (6) on guide rod (4) is connected with downstream installation orifice plate (3), and the float (5) can be under the driving of fluid along guide rod (4)
Slide axially and the circulation passage of variable area is formed with throat's straight length (1.2).
2. the critical flow venturi of principle according to claim 1 of being jammed based on machinery, it is characterised in that：On described
Trip installation orifice plate (2) is identical with the structure of downstream installation orifice plate (3), and the upstream installation orifice plate (2) includes outer shroud (2.1), set
Put the inner ring (2.2) that there is centre bore at the middle part of outer shroud (2.1) and the inwall and inner ring (2.2) that are arranged on outer shroud (2.1)
Outer wall between pole (2.3) composition；The quantity of the pole (2.3) is three, and circumferentially equal along the inwall of outer shroud (2.1)
Even arranged for interval, the sector channel to circulate for liquid is left between adjacent two poles (2.3).
3. the critical flow venturi of principle according to claim 2 of being jammed based on machinery, it is characterised in that：It is described to lead
The both ends of bar (4) are provided with external screw thread, and the center bore inner wall of the inner ring (2.2) is provided with the interior spiral shell to match with external screw thread
Line.
4. the critical flow venturi of principle according to claim 3 of being jammed based on machinery, it is characterised in that：It is described floating
Sub (5) are made up of the float first section (5.1), effective control section (5.2) and float endpiece (5.3) being linked in sequence, the float
First section (5.1) installs orifice plate (3) arrangement, institute towards upstream installation orifice plate (2) arrangement, the float endpiece (5.3) towards downstream
The central axis for stating float (5) overlaps with the central axis of venturi nozzle body (1).
5. the critical flow venturi of principle according to claim 4 of being jammed based on machinery, it is characterised in that：It is described floating
The shape line equation of profile bus of the effective control section (5.2) of sub (5) along its axial direction is determined by following formula：
<mrow>
<mi>Q</mi>
<mo>=</mo>
<mi>&theta;</mi>
<mrow>
<mo>(</mo>
<msup>
<mi>R</mi>
<mn>2</mn>
</msup>
<mo>-</mo>
<msup>
<mi>y</mi>
<mn>2</mn>
</msup>
<mo>)</mo>
</mrow>
<msqrt>
<mfrac>
<mrow>
<mn>2</mn>
<mi>&pi;</mi>
<mi>&rho;</mi>
<mi>k</mi>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>+</mo>
<mi>b</mi>
<mo>)</mo>
</mrow>
</mrow>
<mrow>
<msup>
<mi>y</mi>
<mn>2</mn>
</msup>
<mo>-</mo>
<msup>
<mi>r</mi>
<mn>2</mn>
</msup>
</mrow>
</mfrac>
</msqrt>
<mo>,</mo>
<mrow>
<mo>(</mo>
<mn>0</mn>
<mo><</mo>
<mi>x</mi>
<mo><</mo>
<mi>L</mi>
<mo>)</mo>
</mrow>
</mrow>
In formula：X, y are respectively abscissa and ordinate corresponding to arbitrfary point on profile bus, and Q is critical mass flow rate, and θ is heap soil or fertilizer over and around the roots
C1-esteraseremmer-N property coefficient, R are the radius of throat's straight length (1.2), and ρ is fluid density, and k is the coefficient of elasticity of spring (6), and b is spring
(6) pre compressed magnitude, r are the radius of guide rod (4), and L is the length of effective control section (5.2).
6. the critical flow venturi of principle according to claim 5 of being jammed based on machinery, it is characterised in that：The heap soil or fertilizer over and around the roots
C1-esteraseremmer-N property coefficient θ is relevant with structural parameters and flow parameter, and it embodies form θ=θ (x) and uses CFD method for numerical simulation
It is determined that the characteristic coefficient θ that is jammed, is comprised the following steps that：
1) θ=1 is assumed；
2) according to the θ values in step 1), the shape line equation y=f (x) of float is calculated；
3) determine the structure of float according to the shape line equation obtained in step 2) step, and establish and corresponding be jammed principle based on machinery
Critical flow venturi mathematical calculation model, then obtained using Fluent softwares under different import and export pressure differences
Flow through the corresponding discharge Q of the jet pipenum；
If 4)Using the numerical simulation result in step 3) step, float is calculated under different displacements
θ values, fitting is jammed expression-form θ=θ (x) new characteristic coefficient θ, and the θ values in step 1) are replaced with the new expression formula,
Then repeat step 2) and step 3)；
5) whenWhen, iterative program terminates, and obtained float shape line equation y=f (x) meets designed
Critical flow requirement.
7. the critical flow venturi of the principle of being jammed based on machinery according to claim 5 or 6, it is characterised in that：Institute
The length L of effective control section (5.2) is stated according to maximum allowable operting differential pressure Δ PmaxDetermined by following formula：
<mrow>
<mi>L</mi>
<mo>=</mo>
<mi>&pi;</mi>
<mrow>
<mo>(</mo>
<msup>
<mi>R</mi>
<mn>2</mn>
</msup>
<mo>-</mo>
<msup>
<mi>r</mi>
<mn>2</mn>
</msup>
<mo>-</mo>
<mfrac>
<mi>Q</mi>
<mrow>
<mi>&theta;</mi>
<mi>&pi;</mi>
<msqrt>
<mrow>
<mn>2</mn>
<msub>
<mi>&rho;&Delta;P</mi>
<mrow>
<mi>m</mi>
<mi>a</mi>
<mi>x</mi>
</mrow>
</msub>
</mrow>
</msqrt>
</mrow>
</mfrac>
<mo>)</mo>
</mrow>
<msub>
<mi>&Delta;P</mi>
<mrow>
<mi>m</mi>
<mi>a</mi>
<mi>x</mi>
</mrow>
</msub>
<mo>/</mo>
<mi>k</mi>
</mrow>
In formula：R is the radius of throat's straight length (1.2), and r is the radius of guide rod (4), and Q is critical mass flow rate, and θ is spy of being jammed
Property coefficient, ρ are fluid density, and k is the coefficient of elasticity of spring (6), Δ PmaxFor cavitation does not occur in venturi nozzle body (1)
When import and export between maximum differential pressure.
8. the critical flow venturi of the principle of being jammed based on machinery according to claim 5 or 6, it is characterised in that：Institute
The range for stating float (5) is less than or equal to L.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710641683.2A CN107479585B (en) | 2017-07-31 | 2017-07-31 | Critical flow venturi nozzle based on mechanical choking principle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710641683.2A CN107479585B (en) | 2017-07-31 | 2017-07-31 | Critical flow venturi nozzle based on mechanical choking principle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107479585A true CN107479585A (en) | 2017-12-15 |
| CN107479585B CN107479585B (en) | 2020-07-10 |
Family
ID=60598378
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710641683.2A Active CN107479585B (en) | 2017-07-31 | 2017-07-31 | Critical flow venturi nozzle based on mechanical choking principle |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107479585B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113741557A (en) * | 2020-05-27 | 2021-12-03 | 中国石油化工股份有限公司 | Ground wet steam critical flow control method and device |
| CN114427409A (en) * | 2020-09-09 | 2022-05-03 | 中国石油化工股份有限公司 | Adjustable steam critical flow venturi nozzle and critical flow regulation method |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4139581A (en) * | 1976-09-16 | 1979-02-13 | Swanson Wilbur M | Carburetor |
| JPH0875621A (en) * | 1994-08-31 | 1996-03-22 | Tsukasa Sotsuken:Kk | Constant flow rate sampling apparatus using variable cross section critical flow venturi tube using movable venturi tube |
| DE69521643D1 (en) * | 1994-04-30 | 2001-08-16 | Horiba Ltd | Changeable venturi section for critical flows |
| CN103111212A (en) * | 2013-02-04 | 2013-05-22 | 西安交通大学 | Multi-point introduction structure and flow control mode of venturi mixer |
| CN103573760A (en) * | 2013-10-15 | 2014-02-12 | 西安交通大学 | Device for realizing incompressible fluid critical flow by applying mechanical choking principle |
| CN103851041A (en) * | 2014-03-10 | 2014-06-11 | 西安交通大学 | Critical incompressible fluid flow device with adjustable flow |
| CN105626020A (en) * | 2014-11-07 | 2016-06-01 | 中国石油化工股份有限公司 | Adjustable type steam flow control device |
-
2017
- 2017-07-31 CN CN201710641683.2A patent/CN107479585B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4139581A (en) * | 1976-09-16 | 1979-02-13 | Swanson Wilbur M | Carburetor |
| DE69521643D1 (en) * | 1994-04-30 | 2001-08-16 | Horiba Ltd | Changeable venturi section for critical flows |
| JPH0875621A (en) * | 1994-08-31 | 1996-03-22 | Tsukasa Sotsuken:Kk | Constant flow rate sampling apparatus using variable cross section critical flow venturi tube using movable venturi tube |
| CN103111212A (en) * | 2013-02-04 | 2013-05-22 | 西安交通大学 | Multi-point introduction structure and flow control mode of venturi mixer |
| CN103573760A (en) * | 2013-10-15 | 2014-02-12 | 西安交通大学 | Device for realizing incompressible fluid critical flow by applying mechanical choking principle |
| CN103851041A (en) * | 2014-03-10 | 2014-06-11 | 西安交通大学 | Critical incompressible fluid flow device with adjustable flow |
| CN105626020A (en) * | 2014-11-07 | 2016-06-01 | 中国石油化工股份有限公司 | Adjustable type steam flow control device |
Non-Patent Citations (3)
| Title |
|---|
| C. MISHRA 等: "Development of Cavitation in Refrigerant (R-123) Flow Inside Rudimentary Microfluidic Systems", 《JOURNAL OF MICROELECTROMECHANICAL SYSTEMS》 * |
| ZHENG WEI: "The research of diesel multi-variable venturi intake pipes system", 《2011 INTERNATIONAL CONFERENCE ON MATERIALS FOR RENEWABLE ENERGY & ENVIRONMENT》 * |
| 谢启明 等: "文丘里喷管临界流动函数的研究", 《华东理工大学学报》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113741557A (en) * | 2020-05-27 | 2021-12-03 | 中国石油化工股份有限公司 | Ground wet steam critical flow control method and device |
| CN114427409A (en) * | 2020-09-09 | 2022-05-03 | 中国石油化工股份有限公司 | Adjustable steam critical flow venturi nozzle and critical flow regulation method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107479585B (en) | 2020-07-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107504238B (en) | The adjustable machinery of critical flow is jammed venturi nozzle | |
| CN108168832B (en) | A kind of throat structure improving tube wind tunnel test Reynolds number | |
| CN102218378B (en) | Ultrasonic nonuniform flow nozzle and design method thereof | |
| CN103573760B (en) | A kind of application machine principle of being jammed realizes the device of incompressible fluid critical flow | |
| CN101701837A (en) | Air flow meter with high precision and large range | |
| CN104535121B (en) | A kind of adjustable critical flow venturi nozzle of throat area with aditus laryngis runner | |
| CN108182319B (en) | Supersonic velocity integrated spray pipe design method | |
| CN105626020B (en) | Adjustable steam volume control device | |
| CN106679925A (en) | High-precision control device and control method for micro-mass jet flow rate | |
| CN107479585A (en) | The critical flow venturi for principle of being jammed based on machinery | |
| CN102302989A (en) | Supersonic velocity spray pipe with shared throat part and design method of supersonic velocity spray pipe | |
| CN108387378B (en) | A kind of engine test Propellant Supply low frequency pulsating suppressing method and system | |
| RU2567247C2 (en) | Head for forcing of consolidating liquid mixes at pressure | |
| Zhang et al. | Study of mechanical choked Venturi nozzles used for liquid flow controlling | |
| CN108225726A (en) | A kind of liquid fluid system acoustics closed end inlet experiment boundary condition simulation device | |
| CN103851041B (en) | A kind of flow adjustable incompressible fluid critical flow device | |
| CN201795822U (en) | High-precision large-scale gas flow meter | |
| CN109213213A (en) | A kind of gas flow adjusting method | |
| CN108756835A (en) | Baffling type control valve and well system | |
| CN107449527B (en) | method for improving measurement accuracy of stagnation type total temperature probe | |
| CN105806873B (en) | The cold effect experimental rigs of expansion ratios such as combustion engine turbine blade cooling | |
| CN207499854U (en) | The constant flow water filling jet pipe for principle of being jammed based on machinery | |
| CN205402075U (en) | Fluid damping device of reply pipeline pressure sudden change | |
| CN111062097B (en) | Design method of self-adaptive high-enthalpy molded surface spray pipe | |
| CN111119790B (en) | Equal-dryness separate injection valve for segmented steam injection of thermal recovery horizontal well |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |