CN102375939A - Analysis method for influence of wear in jet pipe servo valve on performance thereof - Google Patents

Abstract

The invention discloses an analysis method for influence of wear in a jet pipe servo valve on performance thereof. The method comprises five major steps: 1, solving wear volume at a radial gap by using a G.Sundarajan plastic deformation model and solving a time function equation of the radial gap; 2, solving wear extent of a working edge by using an erosion model and solving a time function equation of an edge fillet; 3, solving wear extent at a receiving port and solving a time function equation for space from an exit flow port to the receiving port by using the erosion model; 4, solving a slide valve flow equation according to hydro-mechanical knowledge and the fact that flow of a valve port abides by a mass and momentum conservation equation; and 5, solving force acted on two receiving holes by a jet-flow fluid jet according to the oil flow schematic diagram of a nozzle receiver and the hydro-mechanical knowledge, thereby obtaining the influence degree of wear in the jet pipe servo valve on the performance thereof. The method is scientific in conception and easy and convenient in calculation, and has practical value and broad application prospect in the technical field of aerospace jet pipe servo valves.

Description

Wearing and tearing are to the analytical approach of its performance impact in a kind of jet pipe servo valve

One, technical field

The present invention relates to wear and tear in a kind of jet pipe servo valve to the analytical approach of its performance impact; Be specifically related to wear and tear to the impact analysis method of jet pipe servo valve physical dimension and geometrical variations to servo-valve Effect on Performance analytical approach, belong to Aero-Space jet pipe servo valve technical field.

Two, background technology

In recent decades; The development need of aerospace field has the servo-valve highly reliable, that contamination resistance is strong; Though present widely used spray retaining type servo-valve has the dynamic height, responds advantages such as fast; But because contamination resistance is poor, reliability is relatively low, is not suitable for being applied in the Aerospace Products that needs high reliability.In Aerospace Products, begin to adopt the jet pipe servo valve that contamination resistance is strong, reliability is high.Jet pipe servo valve in use because the effect of oil contamination, in the performance degradation mechanism of servo-valve, abrasion mechanism plays an important role.

At present, to the analysis of jet pipe servo valve performance, major part is the analysis to performance impact of fabrication error that servo-valve is made; Utilize simulation softwares such as CFD, AMESim that the servo-valve interior flow field is analyzed, the influence of the structural parameters stream field characteristic of research servo-valve, discharge characteristic, pressure characteristic and the pressure-flow overall characteristic of analysis servo-valve.Influence the physical dimension of servo-valve through analyzing the servo-valve inter deterioration, the method for utilizing geometrical variations to analyze the servo-valve changes of properties does not have, and weares and teares to the analytical approach of its performance impact so the invention provides in a kind of jet pipe servo valve.

Three, summary of the invention

1, purpose: the purpose of this invention is to provide in a kind of jet pipe servo valve and wear and tear to the analytical approach of its performance impact.This method is easy calculates the influence of wearing and tearing to the servo-valve physical dimension, and then analyzes wearing and tearing to the servo-valve Effect on Performance.

2, technical scheme: wearing and tearing specifically comprise the analytical approach of its performance impact in a kind of jet pipe servo valve of the present invention:

(1) the jet pipe servo valve inter deterioration is to the analytical approach of the influence of its physical dimension

The position that wearing and tearing take place jet pipe servo valve mainly comprises: three positions of prestage of spool and valve pocket radial play, guiding valve work seamed edge fillet and jet pipe servo valve.

Relative motion is done in two surfaces of the spool of jet pipe servo valve and valve pocket under certain thickness oil film situation, hard particles makes gap enlargement along with the element pair clearance that is moved into of driving medium and part causes surface abrasion.Thereby bigger particle is able to get into the gap, and the aggravation surface abrasion further enlarges the gap.So circulation causes the chain reaction of wearing and tearing, until complete failure.Therefore, form three-body abrasive wear between spool and the valve pocket.Utilize the flow model of G.Sundarajan

$V=[\mathrm{\β}\×L\×\mathrm{\μ}\×(n+1)]/\{A\×S_e\×[1-C\×(T_c-300)]\×e_c^{n+1}\}$

Calculate wear volume V '=2V.

β is that the elevation angle is greater than the shared ratio of the abrasive particle of critical value in the formula; L is the mill journey; μ is a friction factor; E is strain; N is the strain hardening index; S _eIt is Stress Constants; T _cIt is Kelvin temperature; C is the temperature coefficient of flow stress; A is the correlation parameter of flow stress; e _cIt is surperficial critical strain.

Wearing and tearing back valve core and valve pocket constitute a concentric column, suppose that the radial play after the wearing and tearing is a Δ, the wear volume that can ask $V^{\′}=\mathrm{\π}{(D+\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l-\mathrm{\π}{(d-\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l,$ Therefore can obtain the time dependent function of radial play according to above-mentioned two formula, Δ=f (t).

V ' is a wear volume in the formula; D is the valve pocket interior diameter; D is a valve core diameter; L is wearing and tearing length; Δ is the radial play size; Δ ₀The size of initial diametrical clearance.

Because the intrusion of wearing and tearing and environmental contaminants; Usually contain a large amount of hard particles in the lubricating oil; When fluid is flowed through restriction; To spool seamed edge generation erosion effect; Make and work seamed edge generation erosive wear cause erosive wear to make work seamed edge fillet r increase, utilize erosion model

can obtain wearing and tearing quality m=EAt.

E is a rate of wear in the formula, kg/ (m ²S); K is the constant that depends on by the erosion material; m _pBe the erosion rate of particle, m/s; A is by the area of erosion material, between 0 and 1; V _pBe the erosion rate of particle, m/s; α is the erosion angle of particle; F (α) is for depending on the granule impact angle function of material; N is for being exponential constant, and size depends on material.

Suppose that the radius of corner after the wearing and tearing is r, can be in the hope of wear volume $V^{\′\′}={\∫}_0^{r}2\sqrt{R^2-{(y-R)}^2}(r-\sqrt{r^2-{(y-r)}^2})\mathrm{Dy}$ R is the spool radius in the formula.

Utilize formula EAt=ρ V ", obtain the function of time r=f (t) of work seamed edge radius of corner.

ρ is a fluid density in the formula.

In the prestage of jet pipe servo valve, when fluid when nozzle enters into receiver, receiving port generation erosive wear causes the spacing of jet orifice and receiver hole to increase.Utilization utilizes erosion model

can obtain wearing and tearing quality m '=EAt.

Because the injection stream of jet tubular type is sprayed by single injector, and be accepted the hole and be divided into two strands, the generation of abrasion generally is symmetrical.Can obtain the wear volume formula $V^{\′\′\′}=\frac{2}{3}x\sqrt{2l_{c}x}(d_n-\sqrt{d_n^2-2l_{c}x})$

L in the formula _C0For nozzle arrives the receiver hole initial distance; X=l _c-l _C0d _nBe two receiver hole radiuses.

According to formula EAt=ρ V " ', can be in the hope of the function of time l of the spacing of jet orifice and receiver hole _c=f (t).

2, the servo-valve geometrical variations is to the analytical approach of its Effect on Performance

Have work seamed edge fillet and radial play simultaneously in the guiding valve level work process of stream pipe servo-valve, establishing work seamed edge fillet is r, and radial play is a Δ.According to mobile follow mass-conservation equation and the momentum conservation equation of fluid, can get the guiding valve flow and do at valve port $Q=C_d{A}^{\′}\sqrt{2(p_1-p_2)/\mathrm{\ρ}}=K^{\′}(\sqrt{{(r+\mathrm{\Δ})}^2+{(s+r)}^2}-r),$ Wear and tear to the influence of discharge characteristic thereby obtain in the guiding valve.

C in the formula _dBe coefficient of flow, 0.60-0.70, concerning guiding valve, recommendation is 0.68; S is a slide opening amount size; A ' is the restriction area of passage, B is the restriction width, is the square hole equivalent width for guiding valve, and B=D arcsin (b/D), b are valve pocket rectangular window width, and D is a valve core diameter; p ₁Be charge oil pressure; p ₂Be return pressure; R is a work seamed edge fillet; Δ is a radial play; K ' is a flow gain,

Prestage leans on jet nozzle to spray working fluid, and pressure can be become kinetic energy, and flow converts kinetic energy to pressure energy again after being received by receiving orifice.Obtaining the jet fluid stream therein according to oil flow affacts two power on the receiver hole and is respectively

ρ is a fluid density in the formula; f _RSectional area for receiver hole; f _J1And f _J2Overlapping area for nozzle and left and right sides receiving orifice; λ is that nozzle is to the distance of receiver and the ratio of spout radius, λ=l _c/ r _j

Be the jet beam flow pattern coefficient of jet expansion, confirm by experiment; v _R1, v _R1Be liquid flowing speed in two receiver holes, establish v in the calculating _R1≈ v _R1v ₀₁, v ₀₂Be the speed that reverse direction flow goes out flow in two receiver holes.

Therefore the pressure differential of two receiving ports does The mean value of the load flow of jet pipe amplifier does

With Δ P and q _LRWith linearizing formal representation it

$\mathrm{\ΔP}=\frac{\∂P}{\∂\mathrm{\ϵ}}\mathrm{\ϵ}-\frac{\∂P}{\∂q}{q}_{\mathrm{LR}}=k_{\mathrm{p\ϵ}}\mathrm{\ϵ}-k_{\mathrm{pq}}{q}_{\mathrm{LR}}$

$q_{\mathrm{LR}}=\frac{\∂q}{\∂\mathrm{\ϵ}}\mathrm{\ϵ}-\frac{\∂q}{\∂p}\mathrm{\Δp}=k_{\mathrm{q\ϵ}}\mathrm{\ϵ}-k_{\mathrm{qp}}\mathrm{\Δp}$

ε is the nozzle offset amount in the formula.

Calculating can get the pressure gain of fluid amplifier

Its flow gain does

μ in the formula _jBe nozzle orifice coefficient; P _SBe charge oil pressure; r _jBe spout radius; r _RBe the receiving orifice radius; f ₀For the nozzle offset amount is the overlapping area of 0 o'clock nozzle and left and right sides receiving orifice; f _jBe the cross-section area of nozzle.

In sum, wearing and tearing are to the analytical approach of its performance impact in a kind of jet pipe servo valve of the present invention, and this method is applicable to the jet pipe servo valve of operate as normal in the aerospace field.Concrete steps are following:

Step 1: utilize G.Sundarajan flow model $V=[\mathrm{\β}\×L\×\mathrm{\μ}\×(n+1)]/\{A\×S_e\×[1-C\×(T_c-300)]\×e_c^{n+1}\}$ Try to achieve the wear volume V at radial play place; Suppose the radial play error, obtain wear volume $V^{\′}=\mathrm{\π}{(D+\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l-\mathrm{\π}{(d-\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l,$ Obtain the function of time equation Δ=f (t) of radial play according to equation V '=2V.

In the formula, β is that the elevation angle is greater than the shared ratio of the abrasive particle of critical value; L is the mill journey; E is strain; N is the strain hardening index; S _eIt is Stress Constants; T _cIt is Kelvin temperature; C is the temperature coefficient of flow stress; A is the correlation parameter of flow stress; μ is a friction factor; e _cIt is surperficial critical strain; V ' is a wear volume; D is the valve pocket interior diameter; D is a valve core diameter; L is wearing and tearing length; Δ is the radial play size; Δ ₀The size of initial diametrical clearance.

Step 2: utilize the erosion model Try to achieve the wear extent m '=EAt of work seamed edge, suppose work seamed edge fillet, obtain wear volume $V^{\′\′}={\∫}_0^{r}2\sqrt{R^2-{(y-R)}^2}(r-\sqrt{r^2-{(y-r)}^2})\mathrm{Dy},$ " obtain the function of time equation r=f (t) of seamed edge fillet according to equation EAt=ρ V.

In the formula, E is a rate of wear, kg/ (m ²S); K is the constant that depends on by the erosion material; m _pBe the erosion rate of particle, m/s; A is by the area of erosion material, between 0 and 1; V _pBe the erosion rate of particle, m/s; α is the erosion angle of particle; F (α) is for depending on the granule impact angle function of material; N is for being exponential constant, and size depends on material; R is the radius of corner after wearing and tearing; R is the spool radius; ρ is a fluid density.

Step 3: utilize the erosion model

Try to achieve the wear extent m '=EAt at receiving port place, suppose the spacing of jet orifice, obtain wear volume to receiving port

According to equation EAt=ρ V " ' obtain the function of time equation l of jet orifice to the spacing of receiving port _c=f (t).

In the formula, l _C0For nozzle arrives the receiver hole initial distance; X=l _c-l _C0d _nBe two receiver hole radiuses.

Step 4: have work seamed edge fillet and radial play simultaneously in the guiding valve level work process of stream pipe servo-valve,, try to achieve the guiding valve flow equation according to the mobile mass-conservation equation and the momentum conservation equation followed of fluid at valve port:

$Q=C_d{A}^{\′}\sqrt{2(p_1-p_2)/\mathrm{\ρ}}=K^{\′}(\sqrt{{(r+\mathrm{\Δ})}^2+{(s+r)}^2}-r)$

Wear and tear in the guiding valve to the flow Effect on Performance thereby obtain; C in the formula _dBe coefficient of flow, 0.60-0.70, concerning guiding valve, recommendation is 0.68; A ' is the restriction area of passage,

B is the restriction width, is the square hole equivalent width for guiding valve, and B=Darcsin (b/D), b are valve pocket rectangular window width, and D is a valve core diameter, and S is a slide opening amount size; p ₁Be charge oil pressure; p ₂Be return pressure; R is a work seamed edge fillet, and Δ is a radial play; K ' is a flow gain,

$K=C_{d}B\sqrt{2(p_1-p_2)/\mathrm{\ρ}}.$

Step 5:, obtain the jet fluid stream therein and affact two power on the receiver hole according to nozzle receptacle fluid flow schematic diagram

ρ is a fluid density in the formula; f _RSectional area for receiver hole; f _J1And f _J2Overlapping area for nozzle and left and right sides receiving orifice; λ is that nozzle is to the distance of receiver and the ratio of spout radius, λ=l _c/ r _j Be the jet beam flow pattern coefficient of jet expansion, confirm by experiment; v _R1, v _R1Be liquid flowing speed in two receiver holes, establish v in the calculating _R1≈ v _R1v ₀₁, v ₀₂Be the speed that reverse direction flow goes out flow in two receiver holes.

Therefore the pressure differential of two receiving ports does

The mean value of the load flow of jet pipe amplifier does

With Δ P and q _LRWith linearizing formal representation it

$\mathrm{\ΔP}=\frac{\∂P}{\∂\mathrm{\ϵ}}\mathrm{\ϵ}-\frac{\∂P}{\∂q}{q}_{\mathrm{LR}}=k_{\mathrm{p\ϵ}}\mathrm{\ϵ}-k_{\mathrm{pq}}{q}_{\mathrm{LR}}$

$q_{\mathrm{LR}}=\frac{\∂q}{\∂\mathrm{\ϵ}}\mathrm{\ϵ}-\frac{\∂q}{\∂p}\mathrm{\Δp}=k_{\mathrm{q\ϵ}}\mathrm{\ϵ}-k_{\mathrm{qp}}\mathrm{\Δp}$

ε is the nozzle offset amount in the formula.

Calculating can get the pressure gain of fluid amplifier

Its flow gain does

μ in the formula _jBe nozzle orifice coefficient; P _SBe charge oil pressure; r _jBe spout radius; r _RBe the receiving orifice radius; f ₀For the nozzle offset amount is the overlapping area of 0 o'clock nozzle and left and right sides receiving orifice; f _jBe the cross-section area of nozzle.

3, wearing and tearing are to the analytical approach of its performance impact in a kind of jet pipe servo valve of the present invention, and its advantage and effect are: this method can realize directly drawing performance variation through analyzing wearing and tearing.

Four, description of drawings

Fig. 1 is the guiding valve model synoptic diagram that has the radial play error

Fig. 2 is the guiding valve model synoptic diagram that has the seamed edge fillet

Fig. 3 is the prestage synoptic diagram that has wearing and tearing

Fig. 4 is the guiding valve model synoptic diagram that has radial play and seamed edge fillet

Fig. 5 is the guiding valve flow simulation curve that has fillet and radial play

Fig. 6 is a nozzle receptacle fluid flow schematic diagram

Fig. 7 be zero-bit receive pressure with apart from l _cGraph of a relation

Fig. 8 is a FB(flow block) of the present invention

Symbol description is following among the figure:

Among Fig. 1: 1 is valve pocket (the wide B of being of equivalent aperture), and 2 is spool, and S is a slide opening amount size, and D is the valve pocket interior diameter, and d is a valve core diameter, Δ ₀Be radial play.

Among Fig. 2: S is a slide opening amount size, r ₁Be spool radius of corner, r ₂Be housing square edged orifice seamed edge radius of corner.

Among Fig. 3: 3 is nozzle, and 4 is receiver, d ₁Be jet orifice radius, d _nBe receiving port radius, l _cBe the distance of jet orifice to receiving port.

Among Fig. 4: S is a slide opening amount size, and D is the valve pocket interior diameter, and d is a valve core diameter, Δ ₀Be radial play, r ₁Be spool radius of corner, r ₂Be housing square edged orifice seamed edge radius of corner.

Among Fig. 5: S is a slide opening amount size, and Q is the guiding valve flow.

Among Fig. 6: P _SBe charge oil pressure, v _R1, v _R1Be liquid flowing speed in two receiver holes, v ₀₁, v ₀₂Be the speed that reverse direction flow goes out flow in two receiver holes

Among Fig. 7: x is the distance of jet orifice to receiving port, and P is that zero-bit receives pressure.

Five, embodiment

Wearing and tearing to the analytical approach embodiment of its performance impact are in a kind of jet pipe servo valve of the present invention: the function of time that at first calculates each abrading section geometric parameter.As shown in Figure 1, for there being the guiding valve model synoptic diagram of radial play error.Form three-body abrasive wear between spool and the valve pocket, utilize the flow model of G.Sundarajan

$V=[\mathrm{\β}\×L\×\mathrm{\μ}\×(n+1)]/\{A\×S_e\×[1-C\×(T_c-300)]\×e_c^{n+1}\}$

Calculate wear volume V '=2V.

Wearing and tearing back valve core and valve pocket constitute a concentric column, suppose that the radial play after the wearing and tearing is a Δ, can obtain wear volume $V^{\′}=\mathrm{\π}{(D+\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l-\mathrm{\π}{(d-\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l,$ Therefore can obtain the time dependent function of radial play according to above-mentioned two formula, Δ=f (t).

As shown in Figure 2, for there being the guiding valve model synoptic diagram of seamed edge fillet.Erosive wear takes place in the place at the work seamed edge, makes work seamed edge fillet r increase, and utilizes the erosion model

Can obtain wearing and tearing quality m=FAt, suppose that the radius of corner after the wearing and tearing is r, can be in the hope of wear volume $V^{\′\′}={\∫}_0^{r}2\sqrt{R^2-{(y-R)}^2}(r-\sqrt{r^2-{(y-r)}^2})\mathrm{Dy}.$ Utilize formula EAt=ρ V ", obtain the function of time r=f (t) of work seamed edge radius of corner.

As shown in Figure 3, for there being the prestage synoptic diagram of wearing and tearing.When fluid when nozzle enters into receiver, receiving port generation erosive wear causes the spacing of jet orifice and receiver hole to increase.Utilization utilizes erosion model

can obtain wearing and tearing quality m '=EAt.Because the injection stream of jet tubular type is sprayed by single injector, and be accepted the hole and be divided into two strands, the generation of abrasion generally is symmetrical.Can obtain the wear volume formula

According to formula EAt=ρ V " ', can be in the hope of the function of time l of the spacing of jet orifice and receiver hole _c=f (t).

Obtain the equation of servo-valve performance at last.Its variable is a geometric parameter.As shown in Figure 4, for there being the guiding valve model synoptic diagram of radial play and seamed edge fillet.There are work seamed edge fillet and radial clearance simultaneously in the guiding valve level work process of stream pipe servo valve,, can get the guiding valve flow and do based on the mobile mass-conservation equation and the momentum conservation equation followed of fluid at valve port

$Q=C_{d}A\sqrt{2(p_1-p_2)/\mathrm{\ρ}}=K(\sqrt{{(r+\mathrm{\Δ})}^2+{(s+r)}^2}-r).$

Get radius of corner and radial play and be respectively 0um, 0um, 4um, 4um, 6um, 6um, 8um, 8um, 10um, 10um.According to the flow equation of guiding valve, simulation result is as shown in Figure 5.Work seamed edge fillet and radial play are significantly to the guiding valve performance impact, have a strong impact on the discharge characteristic of little open area, cause its little open area crooked; Flow gain reduces; Increase the nonlinearity of valve, and valve there is leakage when zero-bit, influences the numerical value of quiet consumption flow.Can know that through analyzing radial play is big more, flow gain is low more, and nonlinearity is big more, has leakage rate big more during zero-bit.

As shown in Figure 6, be nozzle receptacle fluid flow schematic diagram.Obtaining the jet fluid stream therein according to oil flow affacts two power on the receiver hole and is respectively

When the nozzle amount of deflection was zero, fluid stream therein affacted two power on the receiver hole and equates, was called zero-bit and received pressure.Zero-bit receives pressure and shows that more greatly the efficient of amplifier is high more, when jet orifice and receiving port size are confirmed, zero-bit receive pressure mainly and between jet orifice and the receiving port apart from l _cRelevant, be illustrated in figure 7 as zero-bit receive pressure with apart from l _cRelation.Visible by Fig. 7, it is maximum near h=0.4mm that zero-bit receives pressure, and zero-bit pressure all descends with the relation of approximately linear when distance is greater than or less than this scope.

See shown in Figure 8ly, wearing and tearing are to the analytical approach of its performance impact in a kind of jet pipe servo valve of the present invention, and these method concrete steps are following:

Step 1: utilize G.Sundarajan flow model $V=[\mathrm{\β}\×L\×\mathrm{\μ}\×(n+1)]/\{A\×S_e\×[1-C\×(T_c-300)]\×e_c^{n+1}\}$ Try to achieve the wear volume V at radial play place, suppose the radial play error, obtain wear volume $V^{\′}=\mathrm{\π}{(D+\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l-\mathrm{\π}{(d-\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l,$ Obtain the function of time equation Δ=f (t) of radial play according to equation V '=2V.

In the formula, β is that the elevation angle is greater than the shared ratio of the abrasive particle of critical value; L is the mill journey; E is strain; N is the strain hardening index; S _eIt is Stress Constants; T _cIt is Kelvin temperature; C is the temperature coefficient of flow stress; A is the correlation parameter of flow stress; μ is a friction factor; e _cIt is surperficial critical strain; V ' is a wear volume; D is the valve pocket interior diameter; D is a valve core diameter; L is wearing and tearing length; Δ is the radial play size; Δ ₀The size of initial diametrical clearance.

Step 2: utilize the erosion model

Try to achieve the wear extent m '=EAt of work seamed edge, suppose work seamed edge fillet, obtain wear volume $V^{\′\′}={\∫}_0^{r}2\sqrt{R^2-{(y-R)}^2}(r-\sqrt{r^2-{(y-r)}^2})\mathrm{Dy},$ " obtain the function of time equation r=f (t) of seamed edge fillet according to equation EAt=ρ V.

In the formula, E is a rate of wear, kg/ (m ²S); K is the constant that depends on by the erosion material; m _pBe the erosion rate of particle, m/s; A is by the area of erosion material, between 0 and 1; V _pBe the erosion rate of particle, m/s; α is the erosion angle of particle; F (α) is for depending on the granule impact angle function of material; N is for being exponential constant, and size depends on material; R is the radius of corner after wearing and tearing; R is the spool radius; ρ is a fluid density.

Step 3: utilize the erosion model

Try to achieve the wear extent m '=EAt at receiving port place, suppose the spacing of jet orifice, obtain wear volume to receiving port According to equation EAt=ρ V " ' obtain the function of time equation l of jet orifice to the spacing of receiving port _c=f (t).

In the formula, l _C0For nozzle arrives the receiver hole initial distance; X=l _c-l _C0d _nBe two receiver hole radiuses.

Step 4: have work seamed edge fillet and radial play simultaneously in the guiding valve level work process of stream pipe servo-valve,, try to achieve the guiding valve flow equation according to the mobile mass-conservation equation and the momentum conservation equation followed of fluid at valve port:

$Q=C_d{A}^{\′}\sqrt{2(p_1-p_2)/\mathrm{\ρ}}=K^{\′}(\sqrt{{(r+\mathrm{\Δ})}^2+{(s+r)}^2}-r)$

C in the formula _dBe coefficient of flow, 0.60-0.70, concerning guiding valve, recommendation is 0.68; A ' is the restriction area of passage,

B is the restriction width, is the square hole equivalent width for guiding valve, and B=D arcsin (b/D), b are valve pocket rectangular window width, and D is a valve core diameter, and S is a slide opening amount size; p ₁Be charge oil pressure; p ₂Be return pressure; R is a work seamed edge fillet, and Δ is a radial play; K ' is a flow gain,

Step 5:, obtain the jet fluid stream therein and affact two power on the receiver hole according to nozzle receptacle fluid flow schematic diagram

ρ is a fluid density in the formula; f _RSectional area for receiver hole; f _J1And f _J2Overlapping area for nozzle and left and right sides receiving orifice; λ is that nozzle is to the distance of receiver and the ratio of spout radius, λ=l _c/ r _j

Be the jet beam flow pattern coefficient of jet expansion, confirm by experiment; v _R1, v _R1Be liquid flowing speed in two receiver holes, establish v in the calculating _R1≈ v _R1v ₀₁, v ₀₂Be the speed that reverse direction flow goes out flow in two receiver holes.

Therefore the pressure differential of two receiving ports does

The mean value of the load flow of jet pipe amplifier does

With Δ P and q _LRWith linearizing formal representation it

$\mathrm{\ΔP}=\frac{\∂P}{\∂\mathrm{\ϵ}}\mathrm{\ϵ}-\frac{\∂P}{\∂q}{q}_{\mathrm{LR}}=k_{\mathrm{p\ϵ}}\mathrm{\ϵ}-k_{\mathrm{pq}}{q}_{\mathrm{LR}}$

$q_{\mathrm{LR}}=\frac{\∂q}{\∂\mathrm{\ϵ}}\mathrm{\ϵ}-\frac{\∂q}{\∂p}\mathrm{\Δp}=k_{\mathrm{q\ϵ}}\mathrm{\ϵ}-k_{\mathrm{qp}}\mathrm{\Δp}$

ε is the nozzle offset amount in the formula.

Calculating can get the pressure gain of fluid amplifier

Its flow gain does

μ in the formula _jBe nozzle orifice coefficient; P _SBe charge oil pressure; r _jBe spout radius; r _RBe the receiving orifice radius; f ₀For the nozzle offset amount is the overlapping area of 0 o'clock nozzle and left and right sides receiving orifice; f _jBe the cross-section area of nozzle.

Claims (1)

1. wear and tear to the analytical approach of its performance impact in a jet pipe servo valve, it is characterized in that: these method concrete steps are following:

Step 1: utilize G.Sundarajan flow model $V=[\mathrm{\β}\×L\×\mathrm{\μ}\×(n+1)]/\{A\×S_e\×[1-C\×(T_c-300)]\×e_c^{n+1}\}$ Try to achieve the wear volume V at radial play place, suppose the radial play error, obtain wear volume $V^{\′}=\mathrm{\π}{(D+\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l-\mathrm{\π}{(d-\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2})}^{2}l,$ Obtain the function of time equation Δ=f (t) of radial play according to equation V '=2V;

In the formula, β is that the elevation angle is greater than the shared ratio of the abrasive particle of critical value; L is the mill journey; E is strain; N is the strain hardening index; S _eIt is Stress Constants; T _cIt is Kelvin temperature; C is the temperature coefficient of flow stress; A is the correlation parameter of flow stress; μ is a friction factor; e _cIt is surperficial critical strain; V ' is a wear volume; D is the valve pocket interior diameter; D is a valve core diameter; L is wearing and tearing length; Δ is the radial play size; Δ ₀The size of initial diametrical clearance;

Step 2: utilize the erosion model Try to achieve the wear extent m '=EAt of work seamed edge, suppose work seamed edge fillet, obtain wear volume $V^{\′\′}={\∫}_0^{r}2\sqrt{R^2-{(y-R)}^2}(r-\sqrt{r^2-{(y-r)}^2})\mathrm{Dy},$ " obtain the function of time equation r=f (t) of seamed edge fillet according to equation EAt=ρ V;

In the formula, E is a rate of wear, kg/ (m ²S); K is the constant that depends on by the erosion material; m _pBe the erosion rate of particle, m/s; A is by the area of erosion material, between 0 and 1; V _pBe the erosion rate of particle, m/s; α is the erosion angle of particle; F (α) is for depending on the granule impact angle function of material; N is for being exponential constant, and size depends on material; R is the radius of corner after wearing and tearing; R is the spool radius; ρ is a fluid density;

Step 3: utilize the erosion model

Try to achieve the wear extent m '=EAt at receiving port place, suppose the spacing of jet orifice, obtain wear volume to receiving port

According to equation EAt=ρ V " ' obtain the function of time equation l of jet orifice to the spacing of receiving port _c=f (t);

In the formula, l _C0For nozzle arrives the receiver hole initial distance; X=l _c-l _C0d _nBe two receiver hole radiuses;

Step 4: have work seamed edge fillet and radial play simultaneously in the guiding valve level work process of stream pipe servo-valve,, try to achieve the guiding valve flow equation according to the mobile mass-conservation equation and the momentum conservation equation followed of fluid at valve port:

$Q=C_d{A}^{\′}\sqrt{2(p_1-p_2)/\mathrm{\ρ}}=K^{\′}(\sqrt{{(r+\mathrm{\Δ})}^2+{(s+r)}^2}-r)$

Wear and tear in the guiding valve to the flow Effect on Performance thereby obtain; C in the formula _dBe coefficient of flow, 0.60-0.70, concerning guiding valve, recommendation is 0.68; A ' is the restriction area of passage,

B is the restriction width, is the square hole equivalent width for guiding valve, and B=Darcsin (b/D), b are valve pocket rectangular window width, and D is a valve core diameter, and S is a slide opening amount size; p ₁Be charge oil pressure; p ₂Be return pressure; R is a work seamed edge fillet, and Δ is a radial play; K ' is a flow gain,

$K=C_{d}B\sqrt{2(p_1-p_2)/\mathrm{\ρ}};$

Step 5:, obtain the jet fluid stream therein and affact two power on the receiver hole according to nozzle receptacle fluid flow schematic diagram

ρ is a fluid density in the formula; f _RSectional area for receiver hole; f _J1And f _J2Overlapping area for nozzle and left and right sides receiving orifice; λ is that nozzle is to the distance of receiver and the ratio of spout radius, λ=l _c/ r _j

Be the jet beam flow pattern coefficient of jet expansion, confirm by experiment; v _R1, v _R1Be liquid flowing speed in two receiver holes, establish v in the calculating _R1≈ v _R1v ₀₁, v ₀₂Be the speed that reverse direction flow goes out flow in two receiver holes;

Therefore the pressure differential of two receiving ports does

The mean value of the load flow of jet pipe amplifier does

With Δ P and q _LRWith linearizing formal representation it

$\mathrm{\ΔP}=\frac{\∂P}{\∂\mathrm{\ϵ}}\mathrm{\ϵ}-\frac{\∂P}{\∂q}{q}_{\mathrm{LR}}=k_{\mathrm{p\ϵ}}\mathrm{\ϵ}-k_{\mathrm{pq}}{q}_{\mathrm{LR}}$

$q_{\mathrm{LR}}=\frac{\∂q}{\∂\mathrm{\ϵ}}\mathrm{\ϵ}-\frac{\∂q}{\∂p}\mathrm{\Δp}=k_{\mathrm{q\ϵ}}\mathrm{\ϵ}-k_{\mathrm{qp}}\mathrm{\Δp}$

ε is the nozzle offset amount in the formula;

Calculating can get the pressure gain of fluid amplifier

Its flow gain does

μ in the formula _jBe nozzle orifice coefficient; P _SBe charge oil pressure; r _jBe spout radius; r _RBe the receiving orifice radius; f ₀For the nozzle offset amount is the overlapping area of 0 o'clock nozzle and left and right sides receiving orifice; f _jBe the cross-section area of nozzle.

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