CN105114334B - Method for monitoring abrasion loss of impeller wear ring of multi-stage centrifugal pump based on computational fluid dynamics theory - Google Patents

Abstract

The invention discloses a method for monitoring abrasion loss of an impeller wear ring of a multi-stage centrifugal pump based on the computational fluid dynamics theory. The method comprises the following steps: 1) modeling a flow field of the complete set of the multi-stage centrifugal pump on the basis of the complete flow field modeling analyzing part of the computational fluid dynamics theory, and calculating the efficiency of the multi-stage centrifugal pump under different wear ring gap size, so as to obtain a curve that the efficiency varies based on the abrasion loss of the wear ring; 2) monitoring the efficiency of the multi-stage centrifugal pump in real time, correspondingly reading pressure and flow data from inlet and outlet pressure transmitters and flow transmitter of the multi-stage centrifugal pump, and reading the motor efficiency and power factors, so as to achieve real-time monitoring of the efficiency of the multi-stage centrifugal pump; 3) acquiring axial and radial vibrating signals, and measuring the radial vibration number of a rotor; 4) determining whether the efficiency is reduced due to the abrasion loss of the wear ring according to the acquired axial and radial vibration signals, and presuming the abrasion loss of the wear ring according to the calculated real-time efficiency and efficiency relationship curve of the multi-stage centrifugal pump.

Description

Based on the centrifugal multistage pump multiple centrifugal pump impeller port ring wear extent monitoring that computational fluid dynamicses are theoretical Method

Technical field

The invention belongs to equipment intelligent diagnosis technical field.

Background technology

As the significant components of multistage centrifugal pump seal, in running, abrasion is inevitable to choma.In engineering In application, the pattern using periodic replacement is keeped in repair for centrifugal pump mouth ring sealing, because different centrifugal pump mouth rings deteriorates speed Rate is different, can lead to keep in repair superfluous or production efficiency reduction using the method for periodic replacement, so real-time monitoring choma Wear condition is even more important.

At present the research of centrifugal pump mouth ring is focused mostly on the optimization to sealing structure and performance, choma gap to rotor and Three aspects such as the impact of choma dynamicss, the impact to centrifugal pump whole machine Flow Field Performance for the choma gap.Old fish et al. profit Record the impact for the performance of centrifugal pump for the size in choma gap with the method tested and calculate, draw preoral loop to pump Can impact bigger than rear choma, and change choma gap on the indices of centrifugal pump optimum operating condition all influential conclusion. J.denecke et al. analyzes the impact to gap sealed sealing property for the seal groove, proposes seal groove and can increase orifice size, Improve sealing effectiveness.Lomakin et al. is theoretical and experimental analysiss clearance seal at exciting force, swashing at clearance seal is proposed The power of shaking can affect critical turn-speed and the stability of rotor.Kurokawaj et al. analyzes centrifugal pump prosopyle czermak space to be justified to impeller The impact of disk friction loss, proposes increase leakage rate and can reduce disc friction losses, optimize choma gap and can optimize performance of centrifugal pump. Alexandrina untaroiu et al., by carrying out Accurate Model to seal clearance flow field, demonstrates by numerical simulation and reality Test that to carry out structure optimization be feasible.Research with regard to centrifugal pump monitoring analysis focuses mostly in faults such as rolling bearing, cavitations.As Zeki kiral et al. is analyzed to defective rolling bearing, simulates vibration signal produced by defect.Zhang Zhigang Et al. propose a kind of based on emd with spectrum kurtosis method Rolling Bearing Fault Character extracting method.Wang Yang et al. utilizes cavitation mould Type analysis centrifugal pump occurs the generation of bubble during cavitation fault to vanish process.Richard b.medvitz et al. adopts biphase Flow model analyzes the performance parameter variations of centrifugal pump under cavitation operating mode.Duan Xiangyang et al. passes through experimental exploring centrifugal pump in vapour Noise under erosion operating mode and vibration signal, the high frequency proposing more than 5khz can be used as the detection foundation of Cavitation Occurred in Centrifugal Pumps.Hole Only et al. according to pump pressure fluctuation situation it is proposed that impeller exciting force is relevant with spiral case cut water, excited frequency for impeller pass through every The frequency of tongue.As can be seen here, at present the faults such as Cavitation Occurred in Centrifugal Pumps, exciting force, bearing are concentrated on for the research of centrifugal pump fault Research, the research for choma concentrates on optimization choma structure and improves the aspect such as choma efficiency, unreal to choma wear extent When monitoring aspect research.

Constituting the theoretical basis of computational fluid dynamicses is the big law of physicss three, the fortune of this three big law fluid system Dynamic description from art of mathematics just constitutes fluid dynamic Basic equation group navier-stokes equation group, the equation Group includes three groups of equations such as equation of continuity, the equation of momentum and energy equation.

Reach its maturity with numerical computation method and be based on computational fluid dynamicses (cfd:computational Fluid dynamics) business software appearance, using cfd to centrifugal pump be simulated with research there is feasibility.Zhu Lei Et al. centrifugal pump key structure such as blade tip clearance, sidewall spacers is calculated, analyze its impact etc. for performance of centrifugal pump. Because choma gap is smaller and flows more complicated in these researchs, usually ignore choma gap in cfd simulation, lead to The impact to centrifugal pump for the choma cannot be considered in research.With the development of computer hardware technology, computing capability greatly promotes, right Start to consider that choma gap exists in the research of centrifugal pump overall performance, make analysis choma gap to centrifugal pump whole machine flow field Impact analysis is possibly realized.As Zhao Weiguo et al. utilizes the different impact to centrifugal pump Flow Field Distribution for the choma gap of cfd simulation, point Analysis choma gap is for the impact of each performance parameter of centrifugal pump.

The present invention carries out flow field modeling using cfd to centrifugal pump, researchs and analyses efficiency, axial force etc. under different choma gaps Parameter Variation, sets up the change curve that the multistage centrifugal efficiency of pump and axial force are worn and torn with choma, proposes one kind and is based on The choma wear extent real-time monitoring evaluation methodology of multi-parameter fusion, has analysed in depth force unbalance, the blocking of impeller channel burn into The impact that fault etc. is monitored to choma wear extent is so that the monitoring for choma wear extent is more accurate.

Content of the invention

The purpose of the present invention be overcome prior art can not to the choma shortcoming that be estimated of abrasion, provide a set of new can Method to be estimated to choma wear extent diagnosing.The method can exclude the interference of other faults during diagnosis, improves The accuracy of choma wear extent assessment.

The invention discloses a kind of centrifugal multistage pump multiple centrifugal pump impeller port ring wear extent monitoring theoretical based on computational fluid dynamicses Method, comprises the steps:

1) set up runner model, based on computational fluid dynamicses theory set up choma gap flow field, impeller channel model and Spiral casing flow passage model, three is carried out assembling the whole machine runner model that can get centrifugal pump.

2) change choma gap size, obtain the whole machine runner model under different choma clearance condition, calculate different chomas The efficiency value of centrifugal multistage pump multiple centrifugal pump under gap, obtains efficiency and blurts out czermak space change curve.

3) the efficiency real-time monitoring of centrifugal multistage pump multiple centrifugal pump, becomes from centrifugal multistage pump multiple centrifugal pump entrance and exit pressure transmitter and flow Send device to read pressure and data on flows respectively, from motor inverter read electric moter voltage, current data, read electric efficiency and Power factor is to calculate multistage centrifugal using import and export flow, inlet and outlet pressure, electric current, voltage, electric efficiency and power factor Pump Real time Efficiency, realizes multistage centrifugal efficiency of pump real-time monitoring.

4) collection axial vibration and radial vibration signal, installs level on the bearing housing of drive end and anti-drive end, hangs down Straight and axial acceleration sensor, gathers the vibration values at centrifugal multistage pump multiple centrifugal pump drive end bearing and non-driven-end bearing.In each axle Hold installation current vortex sensor on the bearing (ball) cover of case, measure rotor radial vibration values.

6) the monitoring part of choma abrasion, determines whether what choma abrasion caused according to axial vibration and radial vibration value Efficiency declines, according to the centrifugal multistage pump multiple centrifugal pump Real time Efficiency calculating and relationship between efficiency history estimating discharge ring wear extent.

Wherein step 1) set up the model that whole machine runner model needs including three parts, due to different piece structure not With its model modelling approach differs.Impeller channel more complicated it is impossible to directly set up model, by vane profile model and leaf Wheel solid domain model subtracts each other sets up impeller channel model.The part that in spiral casing flow passage, pumping chamber is connected with suction chamber adopts space bent Line scans suction chamber tangential direction as scanning track by pumping chamber tangential direction.Each parts assembly is obtained multistage centrifugal Pump whole machine flow field model.Centrifugal multistage pump multiple centrifugal pump flow field model is complicated, and the distortion of the runner such as impeller, pumping chamber is larger, so using four sides Volume mesh carries out stress and strain model to it.

By changing choma gap size, the centrifugal multistage pump multiple centrifugal pump flow field of different choma wear extenies is simulated, using many Level centrifugal pump simulation precision computing formula calculates the multistage centrifugal efficiency of pump under different choma gap sizes, obtains efficiency with choma Gap change curve.The efficiency calculation formula of centrifugal multistage pump multiple centrifugal pump is:

$h=\frac{(v_o^2-v_i^2)}{2g}+\frac{(p_o-p_i)}{\mathrm{\ρ}g}$

$n=\frac{n\mathrm{\π}}{30}{t}_y$

n_e=mhg

$\mathrm{\η}=\frac{n_e}{n}$

v_o: inlet velocity m/s；

v_i: muzzle velocity m/s；

Po: inlet pressure pa；

p_i: outlet pressure pa；

H: lift m；

N: centrifugal pump shaft power w；

N: rotating speed r/min；

t_y: act on the moment of torsion n m around y-axis on impeller；

n_e: centrifugation pump effective power w；

M: mass flow kg/s；

η: efficiency of centrifugal pump.

It is respectively connected to inlet and outlet pressure from centrifugal multistage pump multiple centrifugal pump entrance and exit pressure transmitter and flow transmitter and enter Rate of discharge data, reads electric moter voltage, current data from motor inverter, reads electric efficiency and power factor, utilizes The Real time Efficiency computing formula of pump is calculated the real-time effective power of centrifugal multistage pump multiple centrifugal pump, realizes the multistage centrifugal efficiency of pump and supervises in real time Survey.Because direct measurement multistage centrifugal impeller of pump moment of torsion is more complicated, this patent passes through to introduce current of electric and voltage data meter Calculate shaft power.The efficiency calculation formula of real-time multi-stage pump is:

$h=\frac{(v_o^2-v_i^2)}{2g}+\frac{(p_o-p_i)}{\mathrm{\ρ}g}$

$n=\sqrt{3}uicos\mathrm{\α}*\mathrm{\δ}$

n_e=mhg

$\mathrm{\η}=\frac{n_e}{n}$

v_o: inlet velocity m/s；

v_i: muzzle velocity m/s；

Po: inlet pressure pa；

p_i: outlet pressure pa；

H: lift m；

N: centrifugal pump shaft power w；

U: line voltage v；

I: line current a；

Cos α: power factor；

δ electric efficiency

n_e: centrifugation pump effective power w；

M: mass flow kg/s；

η: efficiency of centrifugal pump.

Collection axial vibration and radial vibration signal, installs level, vertical on the bearing housing of drive end and anti-drive end With axial acceleration sensor, gather the vibration values of centrifugal multistage pump multiple centrifugal pump drive end bearing and non-driven-end bearing.In each bearing housing Bearing (ball) cover on install current vortex sensor, measure rotor radial vibration values.Data acquisition is completed by data collecting system, number Include vibrating sensor, guard grating, data acquisition unit, data application management device according to acquisition system.

Determine whether that the efficiency that choma abrasion causes declines according to axial vibration and radial vibration value, according to calculate Centrifugal multistage pump multiple centrifugal pump Real time Efficiency and relationship between efficiency history estimating discharge ring wear extent.

Brief description

Fig. 1 modeling procedure

Fig. 2 choma monitoring method schematic diagram

Fig. 3 efficiency is with choma abrasion change modeling curve

Fig. 4 wear extent is axial vibration and nominal situation comparison diagram during 0.3mm and 0.7mm

Specific embodiment

Below in conjunction with the accompanying drawings the present invention is described further to the diagnostic method of choma wear extent.

As shown in Figure 1 and Figure 2, the flow process of the present invention includes:

1) set up runner model, based on computational fluid dynamicses theory set up choma gap flow field, impeller channel model and Spiral casing flow passage model, three is carried out assembling the whole machine runner model that can get centrifugal pump.

2) change choma gap size, and then whole machine runner there occurs change, obtains whole under different choma clearance condition Machine runner model.

3) model is carried out calculate analysis, under different choma gap sizes, between the inlet and outlet pressure of centrifugal multistage pump multiple centrifugal pump Pressure reduction change, the relation between the multistage centrifugal efficiency of pump and choma gap length can be drawn by numerical computations.

4) calculate the efficiency of centrifugal multistage pump multiple centrifugal pump, from centrifugal multistage pump multiple centrifugal pump entrance and exit pressure transmitter and flow transmitter It is respectively connected to pressure and data on flows, the real-time effective power of centrifugal multistage pump multiple centrifugal pump can be calculated using the efficiency calculation formula of pump.

5) collection axial vibration and radial vibration signal, installs level on the bearing housing of drive end and anti-drive end, hangs down Straight and axial acceleration sensor, the vibration values of the crucial measuring point of collection centrifugal multistage pump multiple centrifugal pump.The bearing (ball) cover of each bearing housing is pacified Dress current vortex sensor, measures rotor displacement vibration values.

6) the monitoring part of choma abrasion, judges whether it is choma abrasion according to axially and radially vibration, according to efficiency and Relationship between efficiency history estimating discharge ring abrasion condition.

Below various pieces are specifically described.

First, the foundation of runner model

The main flow passage components of centrifugal multistage pump multiple centrifugal pump include entrance, suction chamber, impeller, pumping chamber, outlet, choma gap.To be many The model of individual part forms and obtains setting up whole machine runner model, and due to the difference of different piece structure, its model modelling approach is not Identical.Impeller channel more complicated it is impossible to directly set up model, foundation is subtracted each other by vane profile model and impeller solid domain model Impeller channel model, the part that in spiral casing flow passage, pumping chamber is connected with suction chamber using space curve as scanning track by pressing water Room tangential direction scans suction chamber tangential direction.Each part is assembled in a certain order and obtains the whole machine of centrifugal multistage pump multiple centrifugal pump Flow field model.Centrifugal multistage pump multiple centrifugal pump flow field model is complicated, and the distortion of the runner such as impeller, pumping chamber is larger, so adopting tetrahedral grid Stress and strain model is carried out to it.In order to improve analysis precision, to different parts using different size of mesh opening to obtain higher Mesh quality.And by changing choma gap size, change the whole machine flow field of centrifugal pump, and formed to different chomas mill The simulation of damage amount situation.

2nd, model analysiss calculate

Centrifugal multistage pump multiple centrifugal pump runner model is carried out calculate analysis, obtain between the multistage centrifugal efficiency of pump and choma gap length Relation.Centrifugal multistage pump multiple centrifugal pump runner model is carried out calculate analysis, obtain between the multistage centrifugal efficiency of pump and choma gap length Relation.Asynchronous for choma gap situation is defined as the different faults stage of choma, as normal phase, mild wear rank Section and heavy wear stage, by the calculating to model, can get the centrifugal multistage pump multiple centrifugal pump when choma abrasion is in different phase Efficiency, is analyzed to data, changes with choma gap length, the pressure reduction between the inlet and outlet pressure of centrifugal multistage pump multiple centrifugal pump Change occurs, using multistage pump efficiency calculation formula, can be calculated between the multistage centrifugal efficiency of pump and choma gap length Relation, with choma serious wear, its gap increases, and the efficiency of centrifugal multistage pump multiple centrifugal pump declines.

3rd, centrifugal multistage pump multiple centrifugal pump parameter acquisition

The multistage efficiency of pump is relevant with inlet and outlet pressure, import and export speed and motor performance, real for calculating centrifugal multistage pump multiple centrifugal pump When effective power, be respectively connected to pressure and flow number from centrifugal multistage pump multiple centrifugal pump entrance and exit pressure transmitter and flow transmitter According to.Collection axial vibration and radial vibration signal, install level, vertical and axial direction on the bearing housing of drive end and anti-drive end Acceleration transducer, the vibration values of collection centrifugal multistage pump multiple centrifugal pump key measuring point.Current vortex is installed on the bearing (ball) cover of each bearing housing Sensor, measures rotor displacement vibration values.

4th, choma wear monitoring

In choma wear monitoring evaluation process, by the relation curve of the efficiency that obtained and wear extent, efficiency, axial direction Vibration and four indexs of radial vibration, to carry out the assessment of choma abrasion condition, in practical engineering application, affect multistage centrifugal The factor of the efficiency of pump also includes impeller burn into impeller blocking etc. in addition to choma abrasion.Introduce the exclusion of radial displacement vibration index Impeller corrosion is with the impact of impeller plugging fault so that the accuracy of choma wear fault diagnosis and real-time monitoring choma wear extent Higher.Choma wear-out failure is determined whether according to axially and radially vibration, goes out further according to efficiency and relationship between efficiency history estimating Choma abrasion condition, is estimated to choma fault degree.

5th, experimental verification

Build multistage centrifugal Test-bed for pump, same installation level, vertical, axial acceleration sensor on bearing housing.From many Level centrifugal pump inlet and outlet pressure transmitter and flow transmitter are respectively connected to pressure and data on flows, calculate multistage centrifugal The real-time effective power of pump, introduces current of electric and voltage data calculates shaft power to calculate centrifugal multistage pump multiple centrifugal pump Real time Efficiency.

Bent based on the czermak space change of blurting out of computational fluid dynamicses theoretical modeling analysis mode efficiency as shown in Figure 3 Line, with having changed wear extent previously fabricated and being the choma of 0.3mm and 0.7mm, its axial vibration is than under nominal situation as shown in Figure 4 Decline, calculating its Real time Efficiency is 65.13%, 62.41%, 3 can check in when Real time Efficiency is 65.13% with reference to the accompanying drawings Wear extent be 0.33mm, Real time Efficiency is that when 62.41%, wear extent is 0.74mm, experimental result and previously fabricated wear extent Close.

Claims (5)

1. a kind of centrifugal multistage pump multiple centrifugal pump impeller port ring abrasion quantity monitoring method theoretical based on computational fluid dynamicses, its feature includes Following steps:

1) set up runner model, choma gap flow field, impeller channel model and spiral case are set up based on computational fluid dynamicses theory Runner model, three is carried out assembling the whole machine runner model that can get centrifugal pump；

2) change choma gap size, obtain the whole machine runner model under different choma clearance condition, calculate different choma gaps The efficiency value of lower centrifugal multistage pump multiple centrifugal pump, obtains efficiency and blurts out czermak space change curve；

3) the efficiency real-time monitoring of centrifugal multistage pump multiple centrifugal pump, from centrifugal multistage pump multiple centrifugal pump entrance and exit pressure transmitter and flow transmitter Read pressure and data on flows respectively, read electric moter voltage, current data from motor inverter, read electric efficiency and power Factor is with real using importing and exporting flow, inlet and outlet pressure, electric current, voltage, electric efficiency and power factor calculating centrifugal multistage pump multiple centrifugal pump When efficiency, realize multistage centrifugal efficiency of pump real-time monitoring；

4) collection axial vibration and radial vibration signal, the bearing housing of drive end and anti-drive end is installed level, vertical and Axial acceleration sensor, the vibration values at collection centrifugal multistage pump multiple centrifugal pump drive end bearing and non-driven-end bearing；In each bearing housing Bearing (ball) cover on install current vortex sensor, measure rotor radial vibration values；

5) the monitoring part of choma abrasion, determines whether, according to axial vibration and radial vibration value, the efficiency that choma abrasion causes Decline, according to the centrifugal multistage pump multiple centrifugal pump Real time Efficiency calculating and efficiency blurt out czermak space change curve speculate discharge ring wear extent.

2. method according to claim 1 it is characterised in that: step 1) set up whole machine runner model and need including three portions The model dividing, is subtracted each other by vane profile model and impeller solid domain model and sets up impeller channel model, presses water in spiral casing flow passage The part that room is connected with suction chamber scans suction chamber tangent line as scanning track by pumping chamber tangential direction using space curve Direction；Each parts assembly is obtained the whole machine runner model of centrifugal pump；Impeller, pumping chamber, suction chamber, choma gap adopt four Face volume mesh carries out stress and strain model to it.

3. method according to claim 1 it is characterised in that: step 2) by change choma gap size, to different mouths The centrifugal multistage pump multiple centrifugal pump flow field of ring wear extent is simulated, and is calculated between different chomas using centrifugal multistage pump multiple centrifugal pump simulation precision computing formula The multistage centrifugal efficiency of pump under gap size, obtains efficiency and blurts out czermak space change curve；The efficiency calculation formula of centrifugal multistage pump multiple centrifugal pump For:

$h=\frac{(v_o^2-v_i^2)}{2g}+\frac{(p_o-p_i)}{\mathrm{\ρ}g}$

$n=\frac{n\mathrm{\π}}{30}{t}_y$

n_e=mhg

$\mathrm{\η}=\frac{n_e}{n}$

v_o: inlet velocity m/s；

v_i: muzzle velocity m/s；

p_o: inlet pressure pa；

p_i: outlet pressure pa；

H: lift m；

N: centrifugal pump shaft power w；

N: rotating speed r/min；

t_y: act on the moment of torsion n m around y-axis on impeller；

n_e: centrifugation pump effective power w；

M: mass flow kg/s；

η: efficiency of centrifugal pump.

4. according to claim 1-3 any one methods described it is characterised in that: from centrifugal multistage pump multiple centrifugal pump entrance and exit pressure become Send device and flow transmitter to be respectively connected to inlet and outlet pressure and import and export data on flows, read motor electricity from motor inverter Pressure, current data, read electric efficiency and power factor, and the Real time Efficiency computing formula using pump is calculated multistage centrifugal The real-time effective power of pump, the efficiency calculation formula of real-time multi-stage pump is:

$h=\frac{(v_o^2-v_i^2)}{2g}+\frac{(p_o-p_i)}{\mathrm{\ρ}g}$

$n^{\′}=\sqrt{3}uicos\mathrm{\α}*\mathrm{\δ}$

n_e=mhg

$\mathrm{\η}=\frac{n_e}{n^{\′}}$

v_o: inlet velocity m/s；

v_i: muzzle velocity m/s；

p_o: inlet pressure pa；

p_i: outlet pressure pa；

H: lift m；

Real-time shaft power w of n ': centrifugal pump；

U: line voltage v；

I: line current a；

Cos α: power factor；

δ electric efficiency

n_e: centrifugation pump effective power w；

M: mass flow kg/s；

η: efficiency of centrifugal pump.

5. according to claim 1-3 any one methods described it is characterised in that: do not risen under judging efficiency according to radial vibration Fall be not damage in impeller, leaf destruction, impeller blocking cause, according to axial vibration decline judge by choma abrasion causes Efficiency declines, and is blurted out czermak space change curve according to simulation gained efficiency, is looked into using the centrifugal multistage pump multiple centrifugal pump Real time Efficiency monitoring Find out the choma wear extent corresponding to this efficiency, anti-release choma grinding away over time amount.