A method for evaluating the abrasion life of heavy metal pumps

Abstract

The present invention discloses a method for evaluating the abrasion life of a heavy metal pump. The method evaluates the abrasion life of the pump based on three dimensions: the hydraulic performance of the pump, the strength of the hydraulic components, and the safety of the shaft system. The three dimensions correspond to three failure modes of the pump: wear of the inner and outer diameters of the blades causes a decrease in the head, which does not meet the hydraulic performance requirements of the pump; wear and thinning of the blade thickness causes a decrease in the blade strength; wear on the bearing surface causes an increase in the bearing clearance, which affects the bearing support characteristics and further causes the shaft system to be unable to operate stably. If any dimension does not meet the design requirements, the pump will be shut down. The three dimensions are combined to achieve an accurate evaluation of the pump's service life.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy metal pump life, and in particular to a method for evaluating the abrasion life of a heavy metal pump. Background Art

[0002] Heavy metal pumps are primarily used in fields such as metallurgy, chemical engineering, mechanical processing, and new energy, often operating in environments with high temperatures, high pressures, corrosion, and radiation. Overhauling and replacing heavy metal pumps has always been a cumbersome and costly task. Therefore, extending the design life of heavy metal pumps is a key approach to reducing costs and increasing efficiency. A reasonable and accurate heavy metal pump life assessment method can provide an important basis for pump life design.

[0003] When it comes to life assessment of heavy metal pumps, the industry currently focuses on the long-term, safe, and reliable operation of hydraulic components. Finite element analysis and life testing are the primary methods used for life assessment. This finite element analysis approach primarily involves creating a three-dimensional model of the heavy metal pump and numerically simulating the entire flow path using Fluent to determine the cyclic hydrodynamic loads acting on the impeller and the transient flow field within the pump. ANSYS then analyzes the impeller's stress response. By superimposing various stress loads, fatigue calculations are performed to determine the fatigue life distribution and safety factor of the impeller blades. While this method can reflect the life characteristics of hydraulic components to a certain extent, it fails to account for the impact of long-term wear on the hydraulic performance of the pump and the changes in geometric characteristics of the impeller blades caused by wear. Furthermore, pump life is influenced by multiple dimensions. While impeller strength and life are key indicators, hydraulic performance and shafting stability are also crucial aspects of pump life assessment. Therefore, this approach has limitations. As for the life test, if you want to comprehensively, effectively and accurately evaluate the service life of the pump, the life test time must cover the service life of the pump, which requires a huge investment in time, manpower and material resources.

[0004] Based on this, a reasonable method for assessing the life of heavy metal pumps requires not only a multi-dimensional assessment of the pump's operational lifespan but also the impact of surface erosion on geometric features and key characteristics over the pump's lifespan. Simulation is used to analyze the trends of these multi-dimensional characteristics, and the simulation results are corrected by combining erosion and related characteristic data collected from pump tests. This combined approach enables a multi-dimensional, accurate, and cost-effective assessment of pump lifespan.

[0005] Chinese patent document CN117232575A discloses a "life assessment method, system, equipment and medium for equipment with motors and hydraulic pumps." The method includes: obtaining preset information required for life assessment of the target equipment, the preset information including the vibration signal, noise signal and motor power supply current signal of the target equipment; generating corresponding fault frequency information based on the preset information; decomposing the fault frequency information using empirical mode decomposition to obtain corresponding basic mode components; judging the authenticity of the basic mode components based on the mutual correlation coefficient between the basic mode components and the fault frequency information; performing envelope analysis on the basic mode components judged to be true to obtain spectrum characteristics and extracting fault information based on the spectrum characteristics. The above technical solution has a single dimension for heavy metal pump life assessment and limited assessment accuracy. Summary of the Invention

[0006] The present invention mainly solves the technical problems that the original technical solution has a single dimension for evaluating the life of heavy metal pumps and has limited evaluation accuracy. It provides a method for evaluating the abrasion life of heavy metal pumps. The method evaluates the abrasion life of the pump based on three dimensions: the hydraulic performance of the pump, the strength of the hydraulic components, and the safety of the shaft system. The three dimensions correspond to three failure modes of the pump: wear of the inner and outer diameters of the blades causes a decrease in the head, which does not meet the hydraulic performance requirements of the pump; wear and thinning of the blade thickness causes a decrease in the blade strength; wear on the bearing surface causes an increase in the bearing clearance, which affects the bearing support characteristics and further causes the shaft system to be unable to operate stably. If any dimension does not meet the design requirements, the pump will stop operating. The three dimensions are combined to achieve an accurate evaluation of the pump's operating life.

[0007] The above technical problems of the present invention are mainly solved by the following technical solutions: The present invention comprises the following steps: S1, dividing the abrasion cycle of the pump into stages and conducting a life test under heavy metal media;

[0008] S2 fits the wear volume curves of three dimensions in the stable wear stage based on the test data;

[0009] S3 determines characteristic indicators for evaluating the life of the pump based on the operating parameters of the pump;

[0010] S4 fits the relationship function between the pump's characteristic index and time;

[0011] S5 determines the failure mode based on the pump's characteristic indicators and evaluates the pump life from three dimensions.

[0012] The influence of multiple dimensions on the pump life is considered, including the hydraulic performance of the pump, the strength of the hydraulic components, and the safety of the shaft system. The correlation function of (1) the pump head and time t, (2) the correlation function of the blade stress and time t, and (3) the correlation function of the shaft system critical speed and time t are obtained to evaluate the abrasion life of the pump.

[0013] Preferably, step S1 specifically includes: the pump's wear cycle includes a running-in period, a stable wear phase, and an intense wear phase. The life test involves disassembling the pump every ΔT hours to obtain geometric data on the impeller and bearings after ΔT hours. Based on the correlation between the life cycle curve and the pump's operating status, an overall concept for heavy metal pump life testing is developed: testing is conducted in a heavy metal medium, and the test data is used to extrapolate the wear curves for the impeller and bearings during the running-in period and the stable wear phase. The life test involves disassembling the pump every ΔT hours to obtain geometric data on the impeller and bearings after ΔT hours using methods such as 3D scanning technology, fixed-position dimensional measurement, and weighing.

[0014] Preferably, in step S1, the first stage acquires running-in period data, acquires turning point data for entering the stable stage, and continues the life test after completing the first stage goal to acquire at least three ΔT test data for the stable wear stage.

[0015] As a preferred embodiment, the step S3 specifically includes: examining the hydraulic performance life of the pump, and at the rated speed n, the pump head is less than H min The allowable wear of the blade outer diameter is V1; based on the given impeller stress limit σ s , investigate the impeller strength life, when the blade stress σ>σ s When the blade thickness wear amount V2 is the maximum blade thickness wear amount limited by strength performance; when the shaft stability life is examined, when the bearing wear amount is V3, the bearing stiffness is reduced from the initial stiffness K to K min , at this time the critical speed of the shaft system does not meet n CR >1.25n requirement, the bearing wear V3 is the maximum bearing wear based on the shafting stability limit.

[0016] Preferably, the step S2 includes: the wear curve 1 examines the wear of the inner and outer diameters of the blades and the inner wall surface of the volute chamber, which affects the tip clearance and thus affects the lift. The wear curve 1 has a function of the relationship between the outer diameter wear of the blades and time:

[0017] V1(t)=a 1,n t n +a 1,n-1 t n-1 +a 1,n-2 t n-2 +……+a 1,1 t+a 1,0 (1)

[0018] Where, t is the wear time, in h; V1(t) is the wear amount of the blade outer diameter corresponding to the wear time, in mm; a 1,n 、a 1,n-1 、a 1,n-2 、……、a 1,1 、a1,0 are the coefficients obtained by fitting the experimental data.

[0019] Investigate the hydraulic performance and life of the pump. According to the pump operation requirements, the allowable head range of the pump is (H min , H max Based on CFD analysis, by adjusting the outer diameter wear of the blades and calculating the pump head efficiency, it is found that at the rated speed n, the pump head is less than H min The allowable wear amount of the blade outer diameter is V1.

[0020] Preferably, the step S4 includes fitting a blade outer diameter wear-lift curve based on different blade outer diameter wear-lift results at the rated speed n:

[0021] H(V1)=a 2,n V1 n +a 2,n-1 V1 n-1 +a 2,n-2 V1 n-2 +……+a 2,1 V1+a 2,0 (4)

[0022] Wherein, V1 is the outer diameter wear of the blade, in mm; H(V1) is the pump head corresponding to the outer diameter wear, in m; a 2,n 、a 2,n-1 、a 2,n-2 、……、a 2,1 、a 2,0 is the coefficient obtained by fitting the hydraulic performance analysis based on the wear amount of different blade outer diameters;

[0023] Substituting formula (1) into formula (4), the relationship function of pump head-time t is fitted as shown in formula (5):

[0024] H(t)=a 3,n t n +a 3,n-1 t n-1 +a 3,n-2 t n-2 +……+a 3,1 t+a 3,0 (5)

[0025] Where t is the wear time, in h; H(t) is the pump head corresponding to the wear time, in m; a 3,n 、a 3,n-1 、a 3,n-2 、……、a 3,1 、a 3,0 is the coefficient obtained by fitting according to formula (1) and formula (5).

[0026] Preferably, the step S2 includes: wear curve 2 examining the surface wear of the impeller and hub, which affects the blade thickness and thus the strength performance; the wear curve 2 shows the relationship function between the blade thickness wear and time:

[0027] V2(t)=b 1,n t n +b 1,n-1 t n-1 +b 1,n-2 t n-2 +……+b 1,1 t+b 1,0 (2)

[0028] Where t is the wear time, in h; V2(t) is the blade thickness wear corresponding to the wear time, in mm; b 1,n 、b 1,n-1 、b 1,n-2 ,……,b 1,1 、b 1,0 are the coefficients obtained by fitting the experimental data.

[0029] Based on the impeller stress limit σ given in the relevant specifications s , investigate the strength and life of the impeller. The strength and life of the impeller are affected by the hydraulic load and the change of the blade geometry. Through CFD analysis, the hydraulic load under different blade thickness wear is obtained, and the strength analysis of blades with different thicknesses is carried out. When the blade stress σ>σ s When the blade thickness wear amount V2 is , the blade thickness wear amount V2 is the maximum blade thickness wear amount limited by the strength performance.

[0030] Preferably, the step S4 includes fitting a blade thickness wear amount-blade stress curve based on different blade thickness wear amount-blade stress results at rated speed,

[0031] σ(V2)=b 2,n V2 n +b 2,n-1 V2 n-1 +b 2,n-2 V2 n-2 +……+b 2,1 V2+b 2,0 (6)

[0032] Where V2 is the blade thickness wear, in mm; σ(V2) is the blade stress corresponding to the blade thickness wear, in MPa; b 2,n 、b 2,n-1 、b 2,n-2 ,……,b 2,1 、b 2,0 It is the coefficient obtained by fitting the impeller strength analysis based on the wear amount of different blade thicknesses.

[0033] Substituting formula (2) into formula (6), the relationship function of blade stress-time t is fitted as shown in formula (7):

[0034] σ(t)=b 3,n t n +b 3,n-1 t n-1 +b 3,n-2 t n-2 +……+b 3,1 t+b 3,0 (7)

[0035] Where t is the wear time, in h; σ(t) is the blade stress corresponding to the wear time, in MPa; b 3,n 、b 3,n-1 、b 3,n-2 ,……,b 3,1 、b 3,0 is the coefficient obtained by fitting according to formula (2) and formula (6).

[0036] Preferably, the step S2 includes: the wear curve 3 examines the radial bearing wear, which affects the bearing clearance and thus affects the bearing support capacity and shafting stability; the bearing wear amount-time relationship function of the wear curve 3 is:

[0037] V3(t)=c 1,n t n +c 1,n-1 t n-1 +c 1,n-2 t n-2 +……+c 1,1 t+c 1,0 (3)

[0038] Where t is the wear time, in h; V3(t) is the wear amount of the bearing surface corresponding to the wear time, in mm; c 1,n 、c 1,n-1 、c 1,n-2 、……、c 1,1 、c 1,0 are the coefficients obtained by fitting the experimental data.

[0039] Investigate the stability and life of the shafting system. Bearing wear will increase the bearing clearance, affect the bearing support stiffness, and thus reduce the stability of the shafting system. Through the calculation of bearing characteristics and the analysis of the critical speed of the shafting system, the bearing stiffness corresponding to the hydraulic load under different wear amounts is investigated, and then the critical speed of the shafting system is investigated. When the bearing wear amount is V3, the bearing stiffness is reduced from the initial stiffness K to K min , at this time the critical speed of the shaft system does not meet n CR>1.25n requirement, the bearing wear V3 is the maximum bearing wear based on the shafting stability limit.

[0040] Preferably, the step S4 includes fitting a bearing wear-bearing stiffness curve based on different bearing wear-bearing stiffness results at rated speed:

[0041] K(V3)=c 2,n V3 n +c 2,n-1 V3 n-1 +c 2,n-2 V3 n-2 +……+c 2,1 V3+c 2,0 (8)

[0042] Where V3 is the bearing wear, in mm; K(V3) is the bearing stiffness corresponding to the bearing wear, in N / m; c 2,n 、c 2,n-1 、c 2,n-2 、……、c 2,1 、c 2,0 is the coefficient obtained by fitting the bearing characteristics analysis based on different bearing wear amounts;

[0043] Based on different bearing stiffness values, through the analysis of the critical speed of the shafting system, different bearing stiffness-shafting critical speed curves are obtained. The corresponding function is shown in formula (9):

[0044] n cr (K) = c 3,n K n +c 3,n-1 K n-1 +c 3,n-2 K n-2 +……+c 3,1 K+c 3,0 (9)

[0045] Where K is the bearing stiffness in N / m; n cr (K) is the critical speed of the shaft system corresponding to different bearing stiffness, in r / min; c 3,n 、c 3,n-1 、c 3,n-2 、……、c 3,1 、c 3,0 is the coefficient obtained by fitting the critical speed analysis of the shafting system with different bearing stiffness;

[0046] Substituting the bearing wear-bearing stiffness relationship function in formula (8) into formula (9), the relationship function between bearing wear and critical speed of the shafting is fitted as shown in formula (10):

[0047] ncr (V3) = c 4,n V3 n +c 4,n-1 V3 n-1 +c 4,n-2 V3 n-2 +……+c 4,1 V3+c 4,0 (10)

[0048] Among them, V3 is the bearing wear, unit is mm; n cr (V3) is the critical speed of the shaft system corresponding to different bearing wear amounts, in r / min; c 4,n 、c 4,n-1 、c 4,n-2 、……、c 4,1 、c 4,0 is the coefficient obtained by fitting according to formula (8) and formula (9).

[0049] Substituting the bearing wear-time relationship function in formula (3) into formula (10), the relationship function between the critical speed of the shaft system and time t is fitted as shown in formula (11):

[0050] n cr (t) = c 5,n t n +c 5,n-1 t n-1 +c 5,n-2 t n-2 +……+c 5,1 t+c 5,0 (11)

[0051] Where t is the wear time, in h; n cr (t) is the critical speed of the shaft system corresponding to the wear time, in r / min; c 5,n 、c 5,n-1 、c 5,n-2 、……、c 5,1 、c 5,0 is the coefficient obtained by fitting according to formula (3) and formula (11).

[0052] Based on the three failure modes of the pump, the pump life is evaluated from three dimensions and three pump characteristic indicators. (1) Due to the wear of the impeller outer diameter, the head drops to H min The time point is the pump head life t1, such as Figure 5 As shown; (2) Due to the wear of the blade thickness, the time point when the blade stress exceeds the stress limit of the relevant specification is the blade strength life t2, as shown Figure 7(3) Due to the reduction of support stiffness caused by bearing wear, the stability of the shaft system is reduced. When the critical speed of the shaft system is lower than 125% of the operating speed, the pump does not meet the requirements of stable operation of the shaft system. This moment is the shaft system stability life t3, as shown in Figure 11 As shown in the figure, for the operation status of the pump, if any one of the three characteristic indicators does not meet the design requirements, the pump will stop operating. Therefore, the operating life of the pump should be the minimum value of t1, t2, and t3.

[0053] The beneficial effects of the present invention are: based on the three dimensions of pump hydraulic performance, hydraulic component strength and shaft system safety, the abrasion life of the pump is evaluated. The three dimensions correspond to the three failure modes of the pump: wear of the inner and outer diameters of the blades causes a decrease in head, which does not meet the hydraulic performance requirements of the pump; wear and thinning of the blade thickness causes a decrease in blade strength; wear on the bearing surface causes an increase in bearing clearance, affecting the bearing support characteristics, and thus causing the shaft system to be unable to operate stably. If any dimension does not meet the design requirements, the pump will be shut down. The three dimensions are combined to achieve an accurate evaluation of the pump's service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a flow chart of pump life assessment of the present invention.

[0055] Figure 2 It is a pump failure mode flow chart of the present invention.

[0056] Figure 3 It is a wear curve diagram of the present invention.

[0057] Figure 4 This is a lift-wear curve diagram of the present invention.

[0058] Figure 5 It is a head-time curve diagram of the present invention.

[0059] Figure 6 This is a blade stress-wear estimation curve diagram of the present invention.

[0060] Figure 7 It is an estimated blade stress-time curve diagram of the present invention.

[0061] Figure 8 This is an estimated bearing stiffness-wear curve diagram of the present invention.

[0062] Figure 9 This is a graph of the estimated critical speed of a shafting system versus bearing stiffness according to the present invention.

[0063] Figure 10 This is a graph of estimated critical speed of shafting-wear amount according to the present invention.

[0064] Figure 11This is an estimated shaft critical speed-time curve diagram of the present invention. DETAILED DESCRIPTION

[0065] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the technical solutions of the present invention are further described in detail below through embodiments and in combination with the accompanying drawings. It should be understood that the specific implementation method described here is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0066] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the operations (or steps) as sequential processes, many of the operations (or steps) therein can be performed in parallel, concurrently, or simultaneously. In addition, the order of the operations can be rearranged. The process can be terminated when its operations are completed, but can also have additional steps not included in the figures; the process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0067] The technical solution of the present invention will be further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0068] Example: This example is a method for evaluating the abrasion life of a heavy metal pump. Figure 1 As shown, the following steps are included: S1 divides the pump's wear cycle into stages and conducts a life test under heavy metal media. Specifically, the pump's wear cycle includes a running-in period, a stable wear period, and an intense wear period. The life test is performed every ΔT to obtain geometric data of the impeller and bearings after ΔT hours. Based on the correlation between the life cycle curve and the pump's operating status, the overall concept of the heavy metal pump life test is formulated: conduct tests under heavy metal media, and use the test data to extrapolate the wear curves of the impeller and bearings during the running-in period and the stable wear period. The life test is performed every ΔT, and the impeller and bearing geometric data are obtained after ΔT hours using 3D scanning technology, fixed-position dimensional measurement, and weighing. In the first stage, data is obtained during the running-in period, and data on the turning point of entering the stable period is obtained. After completing the first stage goals, the life test continues to obtain at least three ΔT test data during the stable wear period.

[0069] Based on the experimental data, S2 fits the wear curves of three dimensions in the stable wear stage.

[0070] Among them, wear curve 1 investigates the wear of the inner and outer diameters of the blades and the inner wall of the volute chamber, which affects the tip clearance and thus affects the lift. The blade outer diameter wear function is shown in formula (1); wear curve 2 investigates the wear of the impeller and hub surface, which affects the blade thickness and thus affects the strength performance. The blade thickness wear function is shown in formula (2); wear curve 3 investigates the radial bearing wear, which affects the bearing clearance and thus affects the bearing support capacity and shaft system stability. The bearing wear function is shown in formula (3).

[0071] V1(t)=a 1,n t n +a 1,n-1 t n-1 +a 1,n-2 t n-2 +……+a 1,1 t+a 1,0 (1)

[0072] In formula (1):

[0073] t is the wear time, in h;

[0074] V1(t) is the wear amount of blade outer diameter corresponding to the wear time, in mm;

[0075] a 1,n 、a 1,n-1 、a 1,n-2 、……、a 1,1 、a 1,0 are the coefficients obtained by fitting the experimental data.

[0076] V2(t)=b 1,n t n +b 1,n-1 t n-1 +b 1,n-2 t n-2 +……+b 1,1 t+b 1,0 (2)

[0077] In formula (2):

[0078] t is the wear time, in h;

[0079] V2(t) is the blade thickness wear corresponding to the wear time, in mm;

[0080] b 1,n 、b 1,n-1 、b 1,n-2 ,……,b 1,1 、b 1,0 are the coefficients obtained by fitting the experimental data.

[0081] V3(t)=c 1,n tn +c 1,n-1 t n-1 +c 1,n-2 t n-2 +……+c 1,1 t+c 1,0 (3)

[0082] In formula (3):

[0083] t is the wear time, in h;

[0084] V3(t) is the amount of bearing surface wear corresponding to the wear time, in mm;

[0085] c 1,n 、c 1,n-1 、c 1,n-2 、……、c 1,1 、c 1,0 are the coefficients obtained by fitting the experimental data.

[0086] S3 determines the characteristic index for evaluating the life of the pump based on the operating parameters of the pump. Step S3 specifically includes examining the hydraulic performance life of the pump, and whether the pump head is less than H at the rated speed n. min The allowable wear of the blade outer diameter is V1; based on the given impeller stress limit σ s , investigate the impeller strength life, when the blade stress σ>σ s When the blade thickness wear amount V2 is the maximum blade thickness wear amount limited by strength performance; when the shaft stability life is examined, when the bearing wear amount is V3, the bearing stiffness is reduced from the initial stiffness K to K min , at this time the critical speed of the shaft system does not meet n CR >1.25n requirement, the bearing wear V3 is the maximum bearing wear based on the shafting stability limit.

[0087] S4 fits the relationship function between the pump's characteristic index and time.

[0088] Wear curve 1 examines the wear of the inner and outer diameters of the blades and the inner wall of the volute chamber, which affects the tip clearance and thus the lift. The relationship function between the outer diameter wear of the blade and time in wear curve 1 is:

[0089] V1(t)=a 1,n t n +a 1,n-1 t n-1 +a 1,n-2 t n-2 +……+a 1,1 t+a 1,0 (1)

[0090] Where, t is the wear time, in h; V1(t) is the wear amount of the blade outer diameter corresponding to the wear time, in mm; a 1,n 、a 1,n-1 、a 1,n-2 、……、a 1,1 、a 1,0 are the coefficients obtained by fitting the experimental data.

[0091] Investigate the hydraulic performance and life of the pump. According to the pump operation requirements, the allowable head range of the pump is (H min , H max Based on CFD analysis, by adjusting the outer diameter wear of the blades and calculating the pump head efficiency, it is found that at the rated speed n, the pump head is less than H min The allowable wear amount of the blade outer diameter is V1.

[0092] Based on the different blade outer diameter wear-lift results at rated speed n, the blade outer diameter wear-lift curve is fitted:

[0093] H(V1)=a 2,n V1 n +a 2,n-1 V1 n-1 +a 2,n-2 V1 n-2 +……+a 2,1 V1+a 2,0 (4)

[0094] Wherein, V1 is the outer diameter wear of the blade, in mm; H(V1) is the pump head corresponding to the outer diameter wear, in m; a 2,n 、a 2,n-1 、a 2,n-2 、……、a 2,1 、a 2,0 is the coefficient obtained by fitting the hydraulic performance analysis based on the wear amount of different blade outer diameters;

[0095] Substituting formula (1) into formula (4), the relationship function of pump head-time t is fitted as shown in formula (5):

[0096] H(t)=a 3,n t n +a 3,n-1 t n-1 +a 3,n-2 t n-2 +……+a 3,1 t+a 3,0 (5)

[0097] Where t is the wear time, in h; H(t) is the pump head corresponding to the wear time, in m; a 3,n 、a 3,n-1 、a3,n-2 、……、a 3,1 、a 3,0 is the coefficient obtained by fitting according to formula (1) and formula (5).

[0098] Wear curve 2 examines the surface wear of the impeller and hub, which affects the blade thickness and thus the strength performance; the relationship function between blade thickness wear and time in wear curve 2 is:

[0099] V2(t)=b 1,n t n +b 1,n-1 t n-1 +b 1,n-2 t n-2 +……+b 1,1 t+b 1,0 (2)

[0100] Where t is the wear time, in h; V2(t) is the blade thickness wear corresponding to the wear time, in mm; b 1,n 、b 1,n-1 、b 1,n-2 ,……,b 1,1 、b 1,0 are the coefficients obtained by fitting the experimental data.

[0101] Based on the impeller stress limit σ given in the relevant specifications s , investigate the strength and life of the impeller. The strength and life of the impeller are affected by the hydraulic load and the change of the blade geometry. Through CFD analysis, the hydraulic load under different blade thickness wear is obtained, and the strength analysis of blades with different thicknesses is carried out. When the blade stress σ>σ s When the blade thickness wear amount V2 is , the blade thickness wear amount V2 is the maximum blade thickness wear amount limited by the strength performance.

[0102] Based on the different blade thickness wear-blade stress results at rated speed, the blade thickness wear-blade stress curve is fitted.

[0103] σ(V2)=b 2,n V2 n +b 2,n-1 V2 n-1 +b 2,n-2 V2 n-2 +……+b 2,1 V2+b 2,0 (6)

[0104] Where V2 is the blade thickness wear, in mm; σ(V2) is the blade stress corresponding to the blade thickness wear, in MPa; b 2,n 、b 2,n-1 、b 2,n-2 ,……,b2,1 、b 2,0 It is the coefficient obtained by fitting the impeller strength analysis based on the wear amount of different blade thicknesses.

[0105] Substituting formula (2) into formula (6), the relationship function of blade stress-time t is fitted as shown in formula (7):

[0106] σ(t)=b 3,n t n +b 3,n-1 t n-1 +b 3,n-2 t n-2 +……+b 3,1 t+b 3,0 (7)

[0107] Where t is the wear time, in h; σ(t) is the blade stress corresponding to the wear time, in MPa; b 3,n 、b 3,n-1 、b 3,n-2 ,……,b 3,1 、b 3,0 is the coefficient obtained by fitting according to formula (2) and formula (6).

[0108] Wear curve 3 examines radial bearing wear, which affects bearing clearance and thus bearing support capacity and shafting stability; the bearing wear amount-time relationship function of wear curve 3 is:

[0109] V3(t)=c 1,n t n +c 1,n-1 t n-1 +c 1,n-2 t n-2 +……+c 1,1 t+c 1,0 (3)

[0110] Where t is the wear time, in h; V3(t) is the wear amount of the bearing surface corresponding to the wear time, in mm; c 1,n 、c 1,n-1 、c 1,n-2 、……、c 1,1 、c 1,0 are the coefficients obtained by fitting the experimental data.

[0111] Investigate the stability and life of the shafting system. Bearing wear will increase the bearing clearance, affect the bearing support stiffness, and thus reduce the stability of the shafting system. Through the calculation of bearing characteristics and the analysis of the critical speed of the shafting system, the bearing stiffness corresponding to the hydraulic load under different wear amounts is investigated, and then the critical speed of the shafting system is investigated. When the bearing wear amount is V3, the bearing stiffness is reduced from the initial stiffness K to K min, at this time the critical speed of the shaft system does not meet n CR >1.25n requirement, the bearing wear V3 is the maximum bearing wear based on the shafting stability limit.

[0112] Based on the different bearing wear-bearing stiffness results at rated speed, the bearing wear-bearing stiffness curve is fitted:

[0113] K(V3)=c 2,n V3 n +c 2,n-1 V3 n-1 +c 2,n-2 V3 n-2 +……+c 2,1 V3+c 2,0 (8)

[0114] Where V3 is the bearing wear, in mm; K(V3) is the bearing stiffness corresponding to the bearing wear, in N / m; c 2,n 、c 2,n-1 、c 2,n-2 、……、c 2,1 、c 2,0 is the coefficient obtained by fitting the bearing characteristics analysis based on different bearing wear amounts;

[0115] Based on different bearing stiffness values, through the analysis of the critical speed of the shafting system, different bearing stiffness-shafting critical speed curves are obtained. The corresponding function is shown in formula (9):

[0116] n cr (K) = c 3,n K n +c 3,n-1 K n-1 +c 3,n-2 K n-2 +……+c 3,1 K+c 3,0 (9)

[0117] Where K is the bearing stiffness in N / m; n cr (K) is the critical speed of the shaft system corresponding to different bearing stiffness, in r / min; c 3,n 、c 3,n-1 、c 3,n-2 、……、c 3,1 、c 3,0 is the coefficient obtained by fitting the critical speed analysis of the shafting system with different bearing stiffness;

[0118] Substituting the bearing wear-bearing stiffness relationship function in formula (8) into formula (9), the relationship function between bearing wear and critical speed of the shafting is fitted as shown in formula (10):

[0119] n cr (V3) = c 4,n V3 n +c 4,n-1 V3 n-1 +c 4,n-2 V3 n-2 +……+c 4,1 V3+c 4,0 (10)

[0120] Among them, V3 is the bearing wear, unit is mm; n cr (V3) is the critical speed of the shaft system corresponding to different bearing wear amounts, in r / min; c 4,n 、c 4,n-1 、c 4,n-2 、……、c 4,1 、c 4,0 is the coefficient obtained by fitting according to formula (8) and formula (9).

[0121] Substituting the bearing wear-time relationship function in formula (3) into formula (10), the relationship function between the critical speed of the shaft system and time t is fitted as shown in formula (11):

[0122] n cr (t) = c 5,n t n +c 5,n-1 t n-1 +c 5,n-2 t n-2 +……+c 5,1 t+c 5,0 (11)

[0123] Where t is the wear time, in h; n cr (t) is the critical speed of the shaft system corresponding to the wear time, in r / min; c 5,n 、c 5,n-1 、c 5,n-2 、……、c 5,1 、c 5,0 is the coefficient obtained by fitting according to formula (3) and formula (11).

[0124] S5 determines the failure mode based on the characteristic indicators of the pump and evaluates the pump life from three dimensions. Based on the three failure modes of the pump, the pump life is evaluated from three dimensions and three pump characteristic indicators. (1) Due to the wear of the outer diameter of the impeller, the head drops to H min The time point is the pump head life t1, such as Figure 5 As shown; (2) Due to the wear of the blade thickness, the time point when the blade stress exceeds the stress limit of the relevant specification is the blade strength life t2, as shown Figure 7(3) Due to the reduction of support stiffness caused by bearing wear, the stability of the shaft system is reduced. When the critical speed of the shaft system is lower than 125% of the operating speed, the pump does not meet the requirements of stable operation of the shaft system. This moment is the shaft system stability life t3, as shown in Figure 11 As shown in the figure, for the operation status of the pump, if any one of the three characteristic indicators does not meet the design requirements, the pump will stop operating. Therefore, the operating life of the pump should be the minimum value of t1, t2, and t3.

[0125] The influence of multiple dimensions on the pump life is considered, including the hydraulic performance of the pump, the strength of the hydraulic components, and the safety of the shaft system. The correlation function of (1) the pump head and time t, (2) the correlation function of the blade stress and time t, and (3) the correlation function of the shaft system critical speed and time t are obtained to evaluate the abrasion life of the pump.

[0126] Example

[0127] In order to accurately estimate the abrasion life of heavy metal pumps, the present invention evaluates the abrasion life of the pump based on three dimensions: pump hydraulic performance, hydraulic component strength, and shaft system safety. The pump life evaluation technical route is as follows: Figure 1 As shown. The three dimensions correspond to the three failure modes of the pump: (1) Wear of the inner and outer diameters of the blades causes the head to drop, which does not meet the hydraulic performance requirements of the pump; (2) Wear and thinning of the blade thickness causes the blade strength to decrease; (3) Wear of the bearing surface causes the bearing clearance to increase, affecting the bearing support characteristics, and thus causing the shaft system to be unable to operate stably. Pump failure modes are as follows Figure 2 shown.

[0128] The three-dimensional wear curve is measured through life test, and combined with the wear amount-pump key performance influence curve fitted by finite element analysis; (1) the correlation function of pump head and time t, (2) the correlation function of blade stress and time t, (3) the correlation function of shaft critical speed and time t can be fitted to evaluate the operating life of the pump. The main evaluation contents are as follows: Step 1: The abrasion cycle of the pump is generally divided into three stages, the running-in period, the stable wear stage and the severe wear stage, such as Figure 3 As shown. Based on the correlation between life cycle curves and pump operating conditions, the overall concept for heavy metal pump life testing was developed: tests were conducted in heavy metal media, and the test data was used to extrapolate the wear curves for the impeller and bearings during the run-in period and the stable wear stage. During the life test, the pump was disassembled every ΔT, and geometric data of the impeller and bearings after ΔT hours were obtained using 3D scanning technology, fixed-position dimensional measurement, and weighing. In the first phase, data was collected during the run-in period and the turning point data for the stable stage. After completing the first phase, life testing continued, obtaining at least three ΔT test data during the stable wear stage.

[0129] Step 2: Based on the test data, the wear curves of the three dimensions in the stable wear stage are fitted, such as Figure 3 As shown. Among them, wear curve 1 examines the wear of the inner and outer diameters of the blades and the inner wall of the volute chamber, which affects the blade tip clearance and thus affects the lift. The blade outer diameter wear function is shown in formula (1); wear curve 2 examines the wear of the impeller and hub surface, which affects the blade thickness and thus affects the strength performance. The blade thickness wear function is shown in formula (2); wear curve 3 examines the radial bearing wear, which affects the bearing clearance and thus affects the bearing support capacity and shaft system stability. The bearing wear function is shown in formula (3).

[0130] V1(t)=a 1,n t n +a 1,n-1 t n-1 +a 1,n-2 t n-2 +……+a 1,1 t+a 1,0 (1)

[0131] In formula (1):

[0132] t is the wear time, in h;

[0133] V1(t) is the wear amount of blade outer diameter corresponding to the wear time, in mm;

[0134] a 1,n 、a 1,n-1 、a 1,n-2 、……、a 1,1 、a 1,0 are the coefficients obtained by fitting the experimental data.

[0135] V2(t)=b 1,n t n +b 1,n-1 t n-1 +b 1,n-2 t n-2 +……+b 1,1 t+b 1,0 (2)

[0136] In formula (2):

[0137] t is the wear time, in h;

[0138] V2(t) is the blade thickness wear corresponding to the wear time, in mm;

[0139] b 1,n 、b 1,n-1 、b 1,n-2 ,……,b 1,1 、b 1,0 are the coefficients obtained by fitting the experimental data.

[0140] V3(t)=c 1,n t n +c 1,n-1 t n-1 +c 1,n-2 t n-2 +……+c 1,1 t+c 1,0 (3)

[0141] In formula (3):

[0142] t is the wear time, in h;

[0143] V3(t) is the amount of bearing surface wear corresponding to the wear time, in mm;

[0144] c 1,n 、c 1,n-1 、c 1,n-2 、……、c 1,1 、c 1,0 are the coefficients obtained by fitting the experimental data.

[0145] Step 3: Inspect the hydraulic performance and life of the pump. According to the pump operation requirements, the allowable head range of the pump is (H min , H max Based on CFD analysis, by adjusting the outer diameter wear of the blades and calculating the pump head efficiency, it is found that at the rated speed n, the pump head is less than H min The allowable wear amount of the blade outer diameter is V1.

[0146] Step 4: Based on the blade outer diameter wear-lift results at different rated speeds n, the blade outer diameter wear-lift curve can be fitted, such as Figure 4 As shown, the corresponding function is shown in formula (4). Substituting the relationship function between blade outer diameter wear and time in formula (1) into formula (4), the relationship function between pump head and time t can be fitted as shown in formula (5), and the corresponding pump head-time t curve is as follows Figure 5 shown.

[0147] H(V1)=a 2,n V1 n +a 2,n-1 V1 n-1 +a 2,n-2 V1 n-2 +……+a 2,1 V1+a 2,0 (4)

[0148] In formula (4):

[0149] V1 is the wear of the blade outer diameter, in mm;

[0150] H(V1) is the pump head corresponding to the outer diameter wear, in meters;

[0151] a 2,n 、a 2,n-1 、a 2,n-2 、……、a 2,1 、a 2,0 It is the coefficient obtained by fitting the hydraulic performance analysis based on the wear amount of different blade outer diameters.

[0152] H(t)=a 3,n t n +a 3,n-1 t n-1 +a 3,n-2 t n-2 +……+a 3,1 t+a 3,0 (5)

[0153] In formula (5):

[0154] t is the wear time, in h;

[0155] H(t) is the pump head corresponding to the wear time, in m;

[0156] a 3,n 、a 3,n-1 、a 3,n-2 、……、a 3,1 、a 3,0 is the coefficient obtained by fitting according to formula (1) and formula (5).

[0157] Step 5: Based on the impeller stress limit σ given in the relevant specifications s , investigate the strength and life of the impeller. The strength and life of the impeller are affected by the hydraulic load and the change of the blade geometry. Through CFD analysis, the hydraulic load under different blade thickness wear is obtained, and the strength analysis of blades with different thicknesses is carried out. When the blade stress σ>σ s When the blade thickness wear amount V2 is , the blade thickness wear amount V2 is the maximum blade thickness wear amount limited by the strength performance.

[0158] Step 6: Considering the different blade thickness wear-blade stress results at rated speed, the blade thickness wear-blade stress curve can be fitted, such as Figure 6 As shown, the corresponding function is shown in formula (6). Substituting the blade thickness wear and time relationship function of formula (2) into formula (6), the blade stress-time t relationship function can be fitted as shown in formula (7), and the corresponding blade stress-time t curve is as follows Figure 7 shown.

[0159] σ(V2)=b 2,n V2 n +b 2,n-1V2 n-1 +b 2,n-2 V2 n-2 +……+b 2,1 V2+b 2,0 (6)

[0160] In formula (6):

[0161] V2 is the blade thickness wear, in mm;

[0162] σ(V2) is the blade stress corresponding to the blade thickness wear, in MPa;

[0163] b 2,n 、b 2,n-1 、b 2,n-2 ,……,b 2,1 、b 2,0 It is the coefficient obtained by fitting the impeller strength analysis based on the wear amount of different blade thicknesses.

[0164] σ(t)=b 3,n t n +b 3,n-1 t n-1 +b 3,n-2 t n-2 +……+b 3,1 t+b 3,0 (7)

[0165] In formula (7):

[0166] t is the wear time, in h;

[0167] σ(t) is the blade stress corresponding to the wear time, in MPa;

[0168] b 3,n 、b 3,n-1 、b 3,n-2 ,……,b 3,1 、b 3,0 is the coefficient obtained by fitting according to formula (2) and formula (6).

[0169] Step 7: Investigate the stability and life of the shafting system. Bearing wear will increase the bearing clearance, affect the bearing support stiffness, and thus reduce the stability of the shafting system. Through the calculation of bearing characteristics and the analysis of the critical speed of the shafting system, the bearing stiffness corresponding to the hydraulic load under different wear amounts is investigated, and then the critical speed of the shafting system is investigated. When the bearing wear amount is V3, the bearing stiffness is reduced from the initial stiffness K to K min , at this time the critical speed of the shaft system does not meet n CR >1.25n requirement, the bearing wear V3 is the maximum bearing wear based on the shafting stability limit.

[0170] Step 8: Considering the different bearing wear-bearing stiffness results at rated speed, the bearing wear-bearing stiffness curve can be fitted, such as Figure 8 As shown, the corresponding function is shown in formula (8). Based on different bearing stiffness values, through the analysis of the critical speed of the shaft system, different bearing stiffness-shaft critical speed curves can be obtained, as shown in Figure 9 As shown, the corresponding function is shown in formula (9). Substituting the bearing wear amount-bearing stiffness relationship function of formula (8) into formula (9), the relationship function of bearing wear amount-shaft critical speed can be fitted as shown in formula (10), and the corresponding bearing wear amount-shaft critical speed curve is shown as Figure 10 Based on the experimental fitting curve, the bearing wear amount-time relationship function of formula (3) is substituted into formula (10), and the relationship function of the critical speed of the shaft system-time t is fitted as shown in formula (11), and the corresponding critical speed-time t curve of the shaft system is as follows: Figure 11 shown.

[0171] K(V3)=c 2,n V3 n +c 2,n-1 V3 n-1 +c 2,n-2 V3 n-2 +……+c 2,1 V3+c 2,0 (8)

[0172] In formula (8):

[0173] V3 is the bearing wear, in mm;

[0174] K(V3) is the bearing stiffness corresponding to the amount of bearing wear, in N / m;

[0175] c 2,n 、c 2,n-1 、c 2,n-2 、……、c 2,1 、c 2,0 It is the coefficient obtained by fitting the bearing characteristics analysis based on different bearing wear amounts.

[0176] n cr (K) = c 3,n K n +c 3,n-1 K n-1 +c 3,n-2 K n-2 +……+c 3,1 K+c 3,0 (9)

[0177] In formula (9):

[0178] K is the bearing stiffness, in N / m;

[0179] n cr (K) is the critical speed of the shaft system corresponding to different bearing stiffness, in r / min;

[0180] c 3,n 、c 3,n-1 、c 3,n-2 、……、c 3,1 、c 3,0 It is the coefficient obtained by fitting the critical speed analysis of the shafting with different bearing stiffness.

[0181] n cr (V3) = c 4,n V3 n +c 4,n-1 V3 n-1 +c 4,n-2 V3 n-2 +……+c 4,1 V3+c 4,0 (10)

[0182] In formula (10):

[0183] V3 is the bearing wear, in mm;

[0184] n cr (V3) is the critical speed of the shaft system corresponding to different bearing wear amounts, in r / min;

[0185] c 4,n 、c 4,n-1 、c 4,n-2 、……、c 4,1 、c 4,0 is the coefficient obtained by fitting according to formula (8) and formula (9).

[0186] n cr (t) = c 5,n t n +c 5,n-1 t n-1 +c 5,n-2 t n-2 +……+c 5,1 t+c 5,0 (11)

[0187] In formula (11):

[0188] t is the wear time, in h;

[0189] n cr (t) is the critical speed of the shaft system corresponding to the wear time, in r / min;

[0190] c 5,n 、c 5,n-1 、c5,n-2 、……、c 5,1 、c 5,0 is the coefficient obtained by fitting according to formula (3) and formula (11).

[0191] Step 9: Based on the three failure modes of the pump, the pump life is evaluated from three dimensions and three pump characteristic indicators. (1) Due to the wear of the impeller outer diameter, the head drops to H min The time point is the pump head life t1, such as Figure 5 As shown; (2) Due to the wear of the blade thickness, the time point when the blade stress exceeds the stress limit of the relevant specification is the blade strength life t2, as shown Figure 7 (3) Due to the reduction of support stiffness caused by bearing wear, the stability of the shaft system is reduced. When the critical speed of the shaft system is lower than 125% of the operating speed, the pump does not meet the requirements of stable operation of the shaft system. This moment is the shaft system stability life t3, as shown in Figure 11 As shown in the figure, for the operation status of the pump, if any one of the three characteristic indicators does not meet the design requirements, the pump will stop operating. Therefore, the operating life of the pump should be the minimum value of t1, t2, and t3.

[0192] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0193] The specific embodiments described herein are merely examples of the spirit of the present invention. The above embodiments only express several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that technicians in the technical field to which the present invention belongs can make various modifications or supplements to the described specific embodiments or replace them in a similar manner, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims. For ordinary technicians in this field, multiple variations and improvements can be made without departing from the concept of the present invention. Therefore, the scope of protection of the patent of the present invention should be based on the attached claims.

Claims

1. A method for evaluating the abrasion life of a heavy metal pump, characterized in that: The following steps are involved: S1 divides the pump's abrasion cycle into stages and conducts life tests under heavy metal media; S2 fits the wear volume curves of three dimensions in the stable wear stage based on the test data; S3 determines characteristic indicators for evaluating the life of the pump based on the operating parameters of the pump; S4 fits the relationship function between the characteristic indicators of pump life and time based on the wear curves in three dimensions. S5 determines the failure mode based on the characteristic indicators of pump life and combines the relationship function in S4 to evaluate the pump life from three dimensions. These dimensions include pump hydraulic performance, hydraulic component strength, and shaft system safety, which correspond to three failure modes of the pump: wear of the inner and outer diameters of the blades leads to a decrease in head, which does not meet the pump hydraulic performance requirements; wear and thinning of the blade thickness leads to a decrease in blade strength; The bearing surface is worn, causing the shaft system to be unable to run stably.

2. A heavy metal pump abrasion life assessment method according to claim 1, characterized in that: Specifically, step S1 includes that the abrasion cycle of the pump includes a running-in period, a stable wear stage, and an intense wear stage. The life test is performed by disassembling the pump every ΔT hours to obtain geometric data of the impeller and the bearing after ΔT hours.

3. A heavy metal pump abrasion life assessment method according to claim 2, characterized in that: In step S1, the first stage acquires the running-in period data and the turning point data of entering the stable wear stage. After completing the first stage target, the life test is continued to acquire at least three ΔT test data of the stable wear stage.

4. A heavy metal pump abrasion life assessment method according to claim 1, characterized in that: The step S3 specifically includes examining the hydraulic performance life of the pump, and at the rated speed n, the pump head is less than H min The allowable wear of the blade outer diameter is V1, H min The minimum allowable head of the pump is based on the given impeller stress limit σ s , investigate the impeller strength life, when the blade stress σ>σ s When the blade thickness wear amount V2 is the maximum blade thickness wear amount limited by strength performance; when the shaft stability life is examined, when the bearing wear amount is V3, the bearing stiffness decreases from the initial stiffness K to the minimum stiffness K min , at this time the critical speed of the shaft n CR Does not satisfy n CR >1.25n requirement, n is the rated speed, and the bearing wear V3 is the maximum bearing wear based on the shafting stability limit.

5. A heavy metal pump abrasion life assessment method according to claim 4, characterized in that: The step S2 includes expressing the wear curve of the first dimension as a function of the relationship between the blade outer diameter wear and time.

6. A heavy metal pump abrasion life assessment method according to claim 5, characterized in that: The step S4 includes fitting a blade outer diameter wear-head curve based on different blade outer diameter wear-head results at the rated speed n, substituting the blade outer diameter wear and time relationship function into the curve, and fitting a pump head-time t relationship function.

7. A heavy metal pump abrasion life assessment method according to claim 4, characterized in that: The step S2 includes expressing the wear curve of the second dimension as a function of the relationship between the blade thickness wear and time.

8. A heavy metal pump abrasion life assessment method according to claim 7, characterized in that: The step S4 includes fitting a blade thickness wear amount-blade stress curve based on different blade thickness wear amount-blade stress results at rated speed, substituting the blade thickness wear amount and time relationship function into it, and fitting a blade stress-time t relationship function.

9. A heavy metal pump abrasion life assessment method according to claim 4, characterized in that: The step S2 includes expressing the wear curve of the third dimension as a bearing wear-time relationship function.

10. A heavy metal pump abrasion life assessment method according to claim 9, characterized in that: The step S4 includes fitting a bearing wear-bearing stiffness curve based on different bearing wear-bearing stiffness results at the rated speed, obtaining different bearing stiffness-shafting critical speed curves based on different bearing stiffness values ​​through shafting critical speed analysis, substituting the bearing wear-bearing stiffness relationship function into the curve to fit a bearing wear-shafting critical speed relationship function, and then substituting the bearing wear-time relationship function into the curve to fit a shafting critical speed-time t relationship function.

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