Reliability test method and device for emergency diesel engine of nuclear power plant and storage medium

Abstract

The invention relates to a reliability test method and device for an emergency diesel engine of a nuclear power plant and a storage medium, and the test method comprises the following steps: obtaining the operation condition information of the emergency diesel engine, and obtaining the estimated total use time of parts of a connecting rod power assembly of the emergency diesel engine based on the operation condition information; structural information of a connecting rod power assembly of the emergency diesel engine is obtained, a dynamic calculation model of the connecting rod power assembly is constructed based on the structural information and the operation condition information, and the dynamic calculation model is used for simulating operation of the connecting rod power assembly in preset time; obtaining a wear coefficient of the part, and inputting the wear coefficient and the estimated total use duration into the dynamic calculation model to obtain the part wear loss of the connecting rod power assembly and the maximum wear loss of the cylinder sleeve; and determining the reliability of the emergency diesel engine according to the part abrasion loss and the maximum abrasion loss of the cylinder sleeve. The test method can guarantee reliable operation of the emergency diesel engine.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel engines, and particularly to a reliability test method, device and storage medium for an emergency diesel engine in a nuclear power plant. Background Art

[0002] In a nuclear power plant, as an emergency safety power supply of the nuclear power plant, the operational reliability of the emergency diesel engine is directly related to nuclear safety. The reliability of the emergency diesel engine is related to the safe and stable operation of the nuclear power unit.

[0003] However, wear occurs between the parts of the connecting rod power assembly of the emergency diesel engine, which affects the reliability of the emergency diesel engine. Only by replacing the parts with new ones before excessive wear of the parts can the reliable operation of the emergency diesel engine be ensured. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a reliability test method, device and storage medium for an emergency diesel engine in a nuclear power plant.

[0005] The technical solution adopted by the present invention to solve its technical problems is: to construct a reliability test method for an emergency diesel engine in a nuclear power plant, including the following steps:

[0006] S1: Obtain the operating condition information of the emergency diesel engine, and based on the operating condition information, obtain the estimated total service life of the parts of the connecting rod power assembly of the emergency diesel engine;

[0007] S2: Obtain the structural information of the connecting rod power assembly, and based on the structural information and the operating condition information, construct a dynamic calculation model of the connecting rod power assembly, where the dynamic calculation model is used to simulate the operation of the connecting rod power assembly at a preset time;

[0008] S3: Obtain the wear coefficient of the parts, and input the wear coefficient and the estimated total service life into the dynamic calculation model to obtain the wear amount of the parts;

[0009] S4: Determine the reliability of the emergency diesel engine according to the wear amount of the parts.

[0010] In some embodiments, step S2 includes the following sub-steps:

[0011] S21: Obtain the structural information of the connecting rod power assembly, and construct a three-dimensional geometric model of the connecting rod power assembly according to the structural information;

[0012] S22: Based on the three-dimensional geometric model, combine the performance parameters, fluid parameters and state parameters in the operating condition information to construct a dynamic calculation model of the connecting rod power assembly.

[0013] In some embodiments, the fluid parameter includes the lubricating oil inlet pressure of the connecting rod power assembly, and the lubricating oil inlet pressure adopts the lubricating oil inlet pressure of the cylinder at the downstream of the lubricating oil flow direction in the emergency diesel engine.

[0014] In some embodiments, the calculation formula for the wear amount of the parts in the kinetic calculation model is expressed as:

[0015]

[0016] In the formula, h i is the total wear amount of the i-th surface node in the part within one working cycle, t0 is the time of one working cycle, k is the wear coefficient, p i (t) is the contact pressure at the i-th surface node of the part at time t, v i (t) is the relative speed at the i-th surface node between the part and another part that cooperates with it at time t.

[0017] In some embodiments, the part includes a cylinder liner; the wear amount of the part includes the wear amount of the cylinder liner;

[0018] The reliability test method for the emergency diesel engine of the nuclear power plant further includes a calibration step for the wear coefficient of the cylinder liner, and the steps specifically include:

[0019] S311: Construct a calibration model, and the calibration model is used to simulate the operation of the connecting rod power assembly;

[0020] S312: Obtain the friction experiment data between the piston ring of the connecting rod power assembly and the cylinder liner, and based on the friction experiment data, obtain the operation parameters for inputting into the calibration model;

[0021] S313: Input the operation parameters and a preset wear coefficient into the calibration model to obtain a simulated wear amount;

[0022] S314: Judge whether the difference between the simulated wear amount and the actual wear amount in the friction experiment data is within a preset range. If so, use the preset wear coefficient as the final wear coefficient for calculating the wear amount of the cylinder liner. If not, adjust the preset wear coefficient until the difference between the simulated wear amount and the actual wear amount is within the preset range.

[0023] In some embodiments, step S312 includes the following sub-steps:

[0024] S3121: Obtain the friction experiment data between the piston ring and the cylinder liner, and the friction experiment data includes the stroke and frequency of the friction specimen, as well as the contact load and contact area between the piston ring and the cylinder liner;

[0025] S3122: Obtain the specific pressure based on the contact load and contact area between the piston ring and the cylinder liner;

[0026] S3123: Obtain the average linear velocity based on the stroke and frequency;

[0027] S3124: Obtain the cylinder pressure value for calibration based on the specific pressure, and obtain the rotational speed for calibration and the stroke for calibration based on the average linear velocity;

[0028] Step S313 specifically includes:

[0029] Input the cylinder pressure value for calibration, the rotational speed for calibration, the stroke for calibration, and a preset wear coefficient into the calibration model to obtain the simulated wear amount.

[0030] In some embodiments, the estimated total service life of the cylinder liner includes the total duration of the cylinder liner under the periodic test conditions and the rated operating conditions; the friction experiment data includes lean oil lubrication friction experiment data and oil lubrication friction experiment data;

[0031] In the calibration step of the cylinder liner, obtain the first wear coefficient corresponding to the periodic test conditions of the cylinder liner and the second wear coefficient corresponding to the rated operating conditions of the cylinder liner respectively according to the lean oil lubrication friction experiment data and the oil lubrication friction experiment data;

[0032] In step S3, obtain the wear amount of the cylinder liner according to the first wear coefficient and the duration of the periodic test conditions of the cylinder liner, and the second wear coefficient and the duration of the rated operating conditions of the cylinder liner.

[0033] In some embodiments, the part includes a connecting rod bearing; the estimated total service life of the connecting rod bearing includes the total duration of the connecting rod bearing under the periodic test conditions and the rated operating conditions;

[0034] The reliability test method for the emergency diesel engine of the nuclear power plant further includes a calibration step for the wear coefficient of the connecting rod bearing, and the steps specifically include:

[0035] S321: Obtain the actual wear amount of the connecting rod bearing under at least two different preset time periods; any one of the preset time periods includes the working duration of the connecting rod bearing under the periodic test conditions and the rated operating conditions;

[0036] S322: Input the duration of the periodic test conditions and the duration of the rated operating conditions of the connecting rod bearing in each preset time period into the dynamic calculation model respectively to obtain the slip distance and contact pressure of the connecting rod bearing and the crankshaft of the connecting rod power assembly under the periodic test conditions and the rated operating conditions;

[0037] S323: Obtain the third wear coefficient of the connecting rod bearing under the periodic test condition and the fourth wear coefficient of the connecting rod bearing under the rated operating condition according to the actual wear amounts under at least two different preset time periods, in combination with the slip distances and contact pressures of the crankshaft and the connecting rod bearing under the periodic test condition and the rated operating condition;

[0038] In step S3, obtain the wear amount of the connecting rod bearing according to the third wear coefficient and the duration of the periodic test condition of the connecting rod bearing, and the fourth wear coefficient and the duration of the rated operating condition of the connecting rod bearing. The present invention constructs a reliability test device for an emergency diesel engine in a nuclear power plant. The device includes: a memory, a processor, and a computer program stored on the memory and executable on the processor. The computer program is configured to implement the steps of the above-mentioned reliability test method for the emergency diesel engine in the nuclear power plant.

[0039] The present invention constructs a reliability test device for an emergency diesel engine in a nuclear power plant. The device includes: a memory, a processor, and a computer program stored on the memory and executable on the processor. The computer program is configured to implement the steps of the above-mentioned reliability test method for the emergency diesel engine in the nuclear power plant.

[0040] The present invention constructs a computer-readable storage medium storing a computer program, which when executed by a processor, implements the above-mentioned reliability test method for the emergency diesel engine in the nuclear power plant.

[0041] Implementing the present invention has the following beneficial effects: By constructing a dynamic calculation model of the connecting rod power assembly, simulating the operation of the real connecting rod power assembly, obtaining the predictive maximum wear amount of the parts under the estimated total service life, and then judging the reliability of the emergency diesel engine according to the wear degree of the parts, it is possible to prevent the problem of excessive wear of the parts in the subsequent use process of the emergency diesel engine, thereby ensuring the reliable operation of the emergency diesel engine. Description of the Drawings

[0042] The following will further illustrate the present invention in conjunction with the drawings. In the drawings:

[0043] Figure 1 is the program flow chart of the reliability test method for the emergency diesel engine in the nuclear power plant of the present invention in some embodiments;

[0044] Figure 2 is the program flow chart of the reliability test method for the emergency diesel engine in the nuclear power plant of the present invention in some other embodiments;

[0045] Figure 3 is the flow chart of the wear coefficient calibration of the cylinder liner in the reliability test method for the emergency diesel engine in the nuclear power plant of the present invention.

[0046] Figure 4 It is the flowchart for calibrating the wear coefficient of the connecting rod bearing shell in the reliability test method of the emergency diesel engine in the nuclear power plant of the present invention;

[0047] Figure 5 It is a schematic diagram of the structure of the connecting rod power assembly part in the related technology.

[0048] Figure 6 It is a schematic diagram of the friction experiment of the piston ring and the cylinder liner in the present invention.

[0049] Reference numerals: piston 1; experimental piston ring 11; connecting rod 2; connecting rod bearing shell 21; crankpin 3; main bearing 41; main journal 42; oil passage 6; experimental cylinder liner 7. Specific embodiments

[0050] For a clearer understanding of the technical features, purposes, and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0051] It should be noted that the flowcharts shown in the drawings are only illustrative descriptions, not necessarily including all the contents and operations / steps, nor necessarily executed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0052] The block diagrams shown in the drawings are only functional entities, not necessarily corresponding to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0053] Please refer to Figure 1 , the present invention constructs a reliability test method for the emergency diesel engine in a nuclear power plant, and this method mainly can include the following steps:

[0054] S1: Obtain the operating condition information of the emergency diesel engine in the nuclear power plant, and based on the operating condition information, obtain the estimated total service life of the parts of the connecting rod power assembly of the emergency diesel engine.

[0055] Understandably, for the emergency diesel engine of a nuclear power plant, the operating conditions can include the periodic test condition and the rated operating condition. Among them, the periodic test condition refers to the work of performing a quick start once periodically, and it is required to reach the rated power within a preset number of seconds, but the continuous operation time is not long. Here, it should be added that under the normal operating state of the nuclear power plant, the emergency diesel engine of the nuclear power plant will be in a hot standby state for a long time. During this period, the emergency diesel engine needs to conduct periodic tests to verify the availability and reliability of the quick start of the diesel engine. During each periodic test condition, the emergency diesel engine will reach the rated load state within several seconds, which is the characteristic of the emergency diesel engine of the nuclear power plant different from that in other fields. The rated operating condition refers to the work in which the emergency diesel engine continuously provides the rated power output to meet the needs of the unit for safe shutdown / reactor shutdown under emergency conditions.

[0056] In addition, relevant information about the rated operating condition and the periodic test condition is supplemented here. In the related technology, the rated operating condition includes: the emergency diesel engine starts quickly and needs to reach the rated speed and rated voltage within 15 seconds after receiving the start signal, and automatically loads according to the determined loading sequence. The rated voltage is 6.6 kV, and the rated power output for 200 h is not less than 6000 kW; after operating for 200 h, it can continuously operate at 0.8 times the rated power without time limit. Then, the periodic test condition includes: ① 6.6 kV backup diesel generator set no-load test: once a month, the no-load running time of the diesel engine is generally less than 30 minutes; ② 6.6 kV backup diesel generator set low-power test: once per refueling cycle, the no-load running time of the diesel engine is less than 30 minutes, and the diesel generator set runs at a low load power (40% Pn) for no less than 1 hour; ③ 6.6 kV backup diesel generator set full-power test: once per refueling cycle, the no-load running time of the diesel engine is less than 30 minutes, and the diesel generator set runs at full power for no less than 1 hour; ④ 6.6 kV backup diesel generator set low-power test: once per refueling cycle, the no-load running time of the diesel engine is less than 30 minutes, and the diesel generator set runs at a low load power (40% Pn) for no less than 1 hour.

[0057] Therefore, the operating condition information of the emergency diesel engine of the nuclear power plant includes the information of the periodic test condition and the information of the rated operating condition. The estimated total usage duration can include the duration of the periodic test condition and the duration of the rated operating condition.

[0058] Among them, for the duration of the regular test condition, the operation duration of a single test condition can be obtained from the operation condition information of the emergency diesel engine. At the same time, since the parts of the connecting rod power assembly have requirements for replacement years, the total test condition duration of the parts of the connecting rod power assembly during the period from being put into use to the replacement moment can be calculated by combining them. Then, for the rated operation duration, the operation duration of the rated operation condition of the emergency diesel engine before the test can be obtained from the operation condition information of the emergency diesel engine. Then, estimate the minimum continuous operation duration that the emergency diesel engine can provide under emergency conditions after the test (in the future). Finally, the rated operation duration can be obtained by summing them up. Here, it should be added that since an emergency may occur to the emergency diesel engine before the parts reach the replacement years, it is required that the emergency diesel engine can ensure sufficient continuous operation time under emergency conditions to ensure the safety of the nuclear power unit. Secondly, the estimated minimum continuous operation duration that the emergency diesel engine needs to provide under emergency conditions after the test can be completed based on information such as the frequency of historical emergency occurrences.

[0059] After obtaining the regular test condition duration and the rated operation duration of the parts, the total duration of the two can be used as the target time. Subsequently, determine whether the wear degree of the parts at the target time is within the preset range, so as to determine the reliability of the emergency diesel engine. It should be noted that the reliability mentioned here refers to the reliability of the emergency diesel engine at the target time, not the reliability of the emergency diesel engine at the current test moment.

[0060] In addition, relevant structural information about the connecting rod power assembly of the emergency diesel engine in the nuclear power plant is added here. In the related technology, the emergency diesel engine in the nuclear power plant can be a 18PA6B type diesel engine, which is a four-stroke, medium-speed, single-acting, irreversible, 18-cylinder V-type structure and a diesel engine with a turbocharger. Among them, the connecting rod power assembly is the main working component of the emergency diesel engine; reference can be made to Figure 5, the connecting rod power assembly may include a piston 1, a connecting rod 2, a cylinder liner, piston rings and a crankshaft. The main component of the cylinder liner is graphite cast iron. The cylinder liner is wet and installed in the body. It is pressed between the cylinder head and the spacer sleeve by its shoulder. The cylinder liner and the spacer sleeve are sealed with an upper O-ring, and the cylinder liner and the body are sealed with a lower O-ring. Cooling water flows from the water chamber in the body to the lower part of the cylinder liner, circulates around the cylinder liner and flows upward through the spacer sleeve to the cylinder head. The piston 1 is a combined type. The piston crown is fixed to the piston skirt with several bolts and nuts with clearance sleeves. The piston crown adopts "oscillating" cooling. The lubricating oil comes from the connecting rod 2, flows through the piston pin to the piston crown. There are axial and radial oil holes on the piston pin. After the lubricating oil cools the piston crown, the lubricating oil automatically falls into the common base. The piston pin is floating and is laterally positioned by two snap rings. The snap rings are located in the piston pin bosses. A total of four piston rings are provided, from top to bottom: a top ring, two pressure rings, and an oil scraping ring with a spring assembly. The connecting rod 2 mainly includes an end cover, a big end bearing bush (that is, the connecting rod bearing bush 21), a small end bushing, bolts, etc. The big end bearing bush is divided into two half-bushes, and the small end bushing is a bushing. An oil hole is provided inside the connecting rod 2, and the lubricating oil can enter the piston 1 through the connecting rod 2 for cooling. The crankshaft is integrally forged. The dynamic balance of the crankshaft is achieved by using balance weights. The shape and number of balance weights vary with the number of cylinders of the diesel engine. Each balance weight can be fixed to the crank with several locating sleeves and screws. As Figure 5 shown, the lubricating oil in the oil circuit 5 can enter from the main bearing 41 and, under pressure, flow through the inclined hole and radial hole on the main journal 42 of the crankshaft and the crankpin 3 of the crankshaft to the piston 1.

[0061] In the connecting rod power assembly, abnormal wear is more likely to occur between the cylinder liner and the piston rings, and between the connecting rod bearing bush 21 and the crankpin 3, which has a great impact on the operating reliability of the emergency diesel engine. Therefore, the reliability of the emergency diesel engine can be determined by judging whether the wear degree of the cylinder liner and / or the connecting rod bearing bush 21 at the target time is within the preset range.

[0062] S2: Obtain the structural information of the connecting rod power assembly of the emergency diesel engine, and based on the structural information and the operating condition information, construct a dynamic calculation model of the connecting rod power assembly, which is used to simulate the operation of the connecting rod power assembly at the preset time.

[0063] Understandably, the operating condition information also includes performance parameters, fluid parameters, and state parameters. Based on these parameters and combined with the structural information, a dynamic calculation model of the connecting rod power assembly can be constructed.

[0064] In some embodiments, step S2 may include the following sub-steps:

[0065] S21: Obtain the structural information of the connecting rod power assembly of the emergency diesel engine, and construct a three-dimensional geometric model of the connecting rod power assembly according to the structural information;

[0066] S22: Based on the three-dimensional geometric model of the connecting rod power assembly, combined with the performance parameters, fluid parameters, and state parameters in the operating conditions information, construct a dynamic calculation model of the connecting rod power assembly.

[0067] In step S2, the structural information can be obtained according to the drawings of the emergency diesel engine and combined with the measurement using measurement tools such as three-dimensional measuring instruments on-site.

[0068] Here, it should be added that there are 18 groups of connecting rod power assemblies. Since the cylinders of the diesel engine are arranged in a V shape and parameters such as dimensions and cylinder pressures are basically the same, in order to simplify the calculation, the small differences between cylinders can be ignored, and a single-cylinder model can be adopted. In other words, by judging the wear degree between the parts of a single connecting rod power assembly, the reliability of the entire emergency diesel engine can be evaluated.

[0069] In some embodiments, the structural information includes but is not limited to the following information: cylinder diameter, stroke, connecting rod length, cylinder liner tilt angle, crankshaft offset, piston pin offset, compression height, and the profiles of the piston, piston ring, and cylinder liner. Among them, the cylinder diameter, stroke, connecting rod length, cylinder liner tilt angle, crankshaft offset, piston pin offset, and compression height can be obtained through the product data provided by the manufacturer or reverse measurement. The profiles of the piston, piston ring, and cylinder liner can be obtained by measuring the installation profile in the cold state and then calculating the profile in the hot state through the finite element method.

[0070] The performance parameters can include the number of strokes and piston stiffness. Among them, the number of strokes can be obtained through the product data provided by the manufacturer or reverse measurement. The piston stiffness can be obtained through design data or finite element calculation. The calculation method can refer to related technologies and will not be elaborated in detail here.

[0071] The state parameters can include the engine speed, temperature, and load. These parameters can be obtained through the product data provided by the manufacturer or reverse measurement.

[0072] The fluid parameters can include lubricating oil viscosity, lubricating oil inlet pressure, and cylinder pressure. These parameters can be obtained through the product data provided by the manufacturer or reverse measurement. Secondly, the lubricating oil inlet pressure used to construct the dynamic calculation model can select the lubricating oil inlet pressure parameter of cylinder A1 or B1 of the emergency diesel engine. Because, although the cylinders are arranged symmetrically in a V shape, since the lubricating oil gradually flows from cylinder A9 / B9 to cylinder A1 / B1 inside the body of the emergency diesel engine and the supply oil pressure gradually decreases, using the lubricating oil inlet pressure of cylinder A1 or B1 can improve the reliability of the test results; in other words, the lubricating oil inlet pressure used to construct the dynamic calculation model is preferably the lubricating oil inlet pressure of the cylinder at the end of the lubricating oil flow direction in the emergency diesel engine.

[0073] Secondly, the dynamic calculation model of the connecting rod power assembly can be constructed using the dynamic calculation software Excite PR. When constructing, the three-dimensional geometric model of the connecting rod power assembly is imported into the dynamic calculation software, and performance parameters, fluid parameters, and state parameters are input to form the dynamic calculation model of the target connecting rod power assembly. Subsequently, the dynamic calculation model can be used to simulate the operation of the target connecting rod power assembly.

[0074] S3: Obtain the wear coefficient of the part, and input the wear coefficient and the estimated total service duration into the dynamic calculation model of the connecting rod power assembly to obtain the wear amount of the part.

[0075] In some embodiments, the calculation formula for the wear amount in the dynamic calculation model can be expressed as:

[0076]

[0077] In the formula, h i is the total wear amount of the i-th surface node of the part within one working cycle, t0 is the time of one working cycle, k is the wear coefficient, p i (t) is the contact pressure at the i-th surface node at time t, and v i (t) is the relative velocity between the part at the i-th surface node and another part mating with it at time t.

[0078] Among them, the contact pressure and relative velocity of the part are not affected by the wear coefficient, and these two can be obtained when the dynamic calculation model runs. The wear coefficient can be obtained by referring to the product data of other emergency diesel engines or the experience of relevant personnel in the form of preset input; alternatively, the wear coefficient can be obtained through the calibration steps described below, for details, please refer to the following text.

[0079] It can be understood that the wear amount of the part can be understood as the maximum wear amount of the part, which can reflect the wear degree of the part within a certain period of time. In the present invention, the reliability of the emergency diesel engine is determined by judging the wear degree of the cylinder liner and / or the connecting rod bearing 21 at the target time. In other words, the wear amount of the part can include at least one of the wear amount of the cylinder liner and the wear amount of the connecting rod bearing.

[0080] S4: Determine the reliability of the emergency diesel engine according to the wear amount of the part.

[0081] In some embodiments, step S4 specifically includes:

[0082] Compare the wear amount of the part with a preset limit value; when the wear amount of the part is greater than the preset limit value, it indicates that the wear rate of the part cannot meet the on-site operation requirements, and it is determined that the reliability of the emergency diesel engine is insufficient; while when the wear amount of the part is less than or equal to the preset limit value, it indicates that the wear rate of the part can meet the on-site operation requirements, and it is determined that the emergency diesel engine has sufficient reliability.

[0083] In some embodiments, the limit range of the wear amount of the cylinder liner can be between 0.71 mm and 0.73 mm. Optionally, the limit value of the wear amount of the cylinder liner is 0.72 mm, and more preferably 0.719 mm.

[0084] After determining that the cylinder liner does not meet the on-site operation requirements, the following remedial measures can be taken to ensure the reliable operation of the emergency diesel engine: ① Without changing the structure of the existing equipment, optimize the on-site operation conditions of the emergency diesel engine; for example, extend the starting time of the emergency diesel engine or change the lubricating oil parameters to avoid abnormal wear of the cylinder liner. ② Optimize the piston ring structure; for example, add a wear-resistant coating, etc., to avoid excessive wear of the cylinder liner. ③ According to the difference between the wear amount of the cylinder liner and the preset limit value, formulate a reasonable preventive replacement cycle for the cylinder liner; in other words, replace the diesel engine cylinder liner preventively before the wear amount of the cylinder liner exceeds the limit value.

[0085] The limit range and remedial measures for the wear amount of the connecting rod bearing shell can refer to the wear amount of the above-mentioned cylinder liner, and will not be elaborated here.

[0086] In summary, the present invention tests the reliability of the emergency diesel engine by obtaining the maximum wear amount of the cylinder liner and / or the connecting rod bearing shell 21; wherein, by constructing a dynamic calculation model of the connecting rod power assembly, simulating the operation of the connecting rod power assembly at the target time to obtain the maximum wear amount of the cylinder liner and / or the connecting rod bearing shell 21; then, when it is found that the wear rate of the cylinder liner and / or the connecting rod bearing shell 21 is too fast, remedial measures can be taken to ensure the reliable operation of the emergency diesel engine.

[0087] Then, more preferably, it can be referred to Figure 2 , the test method of the present invention further includes the step of calibrating the wear coefficient of the part to ensure the accuracy of the wear amount of the part. In some embodiments, the wear coefficient of the cylinder liner can be calibrated by using the friction and wear test between the piston ring and the cylinder liner. It can be referred to Figure 3 , the calibration step of the wear coefficient of the cylinder liner can include:

[0088] S311: Construct a calibration model of the connecting rod power assembly; this calibration model is used to simulate the operation of the connecting rod power assembly at the preset time;

[0089] S312: Obtain the friction experimental data between the piston ring and the cylinder liner, and based on the friction experimental data, obtain the operating parameters for inputting into the calibration model;

[0090] S313: Input the operating parameters and the preset wear coefficient into the calibration model to obtain the simulated wear amount;

[0091] S314: Determine whether the difference between the simulated wear amount and the actual wear amount obtained from the friction experiment data is within the preset range. If so, use the preset wear coefficient as the final wear coefficient for the dynamic calculation model. If not, adjust the wear coefficient until the difference between the simulated wear amount and the actual wear amount is within the preset range.

[0092] Understandably, reference can be made to Figure 6 , the friction experiment between the piston ring and the cylinder liner can be: set the piston ring at the top of the cylinder liner and make the piston ring contact the top of the cylinder liner; the piston ring is configured to reciprocate on the cylinder liner; meanwhile, a heating device is provided at the bottom of the cylinder liner so that the piston ring and the cylinder liner conduct friction in a heated environment. Here, it is further explained that Figure 6 the structure therein only serves as a schematic illustration, and the actual structures of the piston ring and the cylinder liner shall be based on the actual situation. Secondly, in Figure 6 , the arrow located on the upper side indicates the direction of the load, the arrow located in the middle indicates the moving direction of the piston ring, and the arrow located at the lower part indicates heating of the cylinder liner.

[0093] The piston ring and the cylinder liner used in the friction experiment do not refer to the piston ring and the cylinder liner of the test target, but refer to the experimental cylinder liner 7 and the experimental piston ring 11 of the same size as the piston ring and the cylinder liner of the test target. The experimental cylinder liner 7 and the experimental piston ring 11 can be spare parts or obtained by disassembling other diesel engines; secondly, the experimental cylinder liner 7 and the experimental piston ring 11 can be used to only intercept part of the structure for the experiment by using tools, because the sizes of the cylinder liner and the piston ring are large. If the whole cylinder liner and the whole piston ring are used, it will only increase the experimental difficulty.

[0094] The friction experiment data includes the stroke and frequency of the friction specimen, as well as the contact load and the contact area between the experimental cylinder liner 7 and the experimental piston ring 11. Among them, the stroke and frequency of the friction specimen and the contact load between the experimental cylinder liner 7 and the experimental piston ring 11 are preset values and belong to the experimental operating parameters of the friction experiment. The contact area between the experimental cylinder liner 7 and the experimental piston ring 11 can be obtained by removing the parts and measuring the worn area between the experimental cylinder liner 7 and the experimental piston ring 11 after the friction experiment.

[0095] The construction of the calibration model can refer to the above kinetic calculation model, which will not be elaborated here. The operating parameters input into the calibration model include cylinder pressure value, rotational speed, and stroke. Here, it can be supplemented that the establishment of the calibration model is to try to match the working conditions of the friction experiment; the cylinder pressure value, rotational speed, and stroke used in the calibration model are constant values, which is different from the above kinetic calculation model. After constructing the calibration model, it is necessary to set the cylinder pressure value to the cylinder pressure value required to achieve the same specific pressure as the friction test, and apply the rotational speed and stroke with the same average linear velocity as in the friction test in the calibration model. Therefore, the structural dimensions and rotational speed of the calibration model can be different from those of the above kinetic calculation model, and it is only necessary that the specific pressure and linear velocity used in the calibration model are consistent with those in the friction experiment.

[0096] Therefore, step S312 can be specifically as follows:

[0097] S3121: Obtain the friction experiment data between the experimental cylinder liner 7 and the experimental piston ring 11. This friction experiment data includes the stroke and frequency of the friction specimen, as well as the contact load and contact area between the piston ring and the cylinder liner;

[0098] S3122: Obtain the specific pressure based on the contact load and contact area between the experimental cylinder liner 7 and the experimental piston ring 11;

[0099] S3123: Obtain the average linear velocity based on the stroke and frequency;

[0100] S3124: Obtain the cylinder pressure value for calibration based on the specific pressure, and obtain the rotational speed for calibration and the stroke for calibration based on the average linear velocity;

[0101] Step S313 can be specifically as follows:

[0102] S3131: Input the cylinder pressure value for calibration, the rotational speed for calibration, the stroke for calibration, and a preset wear coefficient into the calibration model to obtain the simulated wear amount.

[0103] Here, it can be supplemented that the specific pressure P = contact load F / contact area S. The average linear velocity V = stroke L × frequency f.

[0104] Immediately afterwards, in step S28, by adjusting the wear coefficient, if the simulated wear amount is too small, increase the wear coefficient; if the simulated wear amount is too large, decrease the wear coefficient until the calculated simulated wear amount and the actual wear amount in the friction test are within the error range; the wear coefficient at this time is used as the calibration value for subsequent calculation of the maximum wear amount of the cylinder liner.

[0105] Preferably, the friction experiment between the experimental cylinder liner 7 and the experimental piston ring 11 can include a lean oil lubrication friction experiment and an oil lubrication friction experiment, corresponding to the periodic test working condition and the rated operating condition respectively.

[0106] In some embodiments, the working conditions of the lean oil lubrication friction experiment may be as follows: Before each friction test, apply a layer of lubricating oil on the top surface of the experimental cylinder liner 7; the temperature is 140°C to 160°C, the reciprocating friction motion frequency is 20 Hz, and the stroke is 1 mm. The working conditions of the oil lubrication friction experiment may be as follows: The friction specimen is tested in the lubricating oil, that is, the experimental cylinder liner 7 and the experimental piston ring 11 are immersed in the lubricating oil; the temperature is 140°C to 160°C, the reciprocating friction motion frequency is 20 Hz, and the stroke is 1 mm. Among them, the first wear coefficient K1 obtained based on the lean oil lubrication test data is used to simulate the insufficient lubrication condition of the emergency diesel engine during the regular test, while the second wear coefficient K2 obtained from the oil lubrication test data is used to simulate the sufficient lubrication condition of the emergency diesel engine during the rated power operation.

[0107] In other words, in step S3, the following sub-steps may be included:

[0108] S315: Input the duration of the regular test condition of the emergency diesel engine and the first wear coefficient obtained based on the lean oil lubrication test data into the dynamic calculation model of the connecting rod power assembly to obtain the wear amount of the cylinder liner under the regular test condition;

[0109] S316: Input the duration of the rated operation condition of the emergency diesel engine and the second wear coefficient obtained based on the oil lubrication test data into the dynamic calculation model of the connecting rod power assembly to obtain the wear amount of the cylinder liner under the rated operation condition;

[0110] S317: Obtain the wear amount of the cylinder liner according to the wear amounts of the cylinder liner under the regular test condition and the rated operation condition.

[0111] It can be understood that the wear amount of the cylinder liner is equal to the sum of the wear amounts of the connecting rod power assembly under the regular test condition and the rated operation condition. By calibrating the wear coefficients under different working conditions, accurate input can be provided for the wear simulation of the cylinder liner / piston ring of the connecting rod power assembly.

[0112] Secondly, the calibrated dynamic calculation model can be used to analyze the wear characteristics of the cylinder liner and identify the key influencing factors affecting the wear rate of the cylinder liner.

[0113] In some embodiments, the key influencing factors of cylinder liner wear include: the rapid start time of the diesel engine, the diesel operation load, the piston ring-cylinder liner clearance, and the piston ring-cylinder liner wear coefficient. By studying the sensitivity of different influencing factors to the wear rate, the most critical influencing factor can be identified and used as the direction for subsequent improvement of the emergency diesel engine.

[0114] In some embodiments, the wear coefficient of the connecting rod bearing 21 can be calibrated based on on-site operation data. It should be added here that since the cost of the crankshaft is relatively high, it will be too costly to test it through wear tests. Therefore, in the present invention, a calibration method based on on-site operation data is provided.

[0115] For reference Figure 4 , the calibration steps of the wear coefficient of the connecting rod bearing 21 may include:

[0116] S321: Obtain the actual wear amount of the connecting rod bearing 21 under at least two different preset time periods; any preset time period includes the first working condition duration of the connecting rod bearing 21 under the regular test working condition and the second working condition duration of the connecting rod bearing 21 under the rated operation working condition.

[0117] It can be understood that the preset time period is defined as the time period during which the connecting rod bearing 21 has experienced the regular test working condition and the rated operation working condition. Therefore, the preset time period can include the working condition duration of the connecting rod bearing 21 under the regular test working condition and the working condition duration of the connecting rod bearing 21 under the rated operation working condition.

[0118] In some embodiments, any actual wear amount can be obtained by the method of manual measurement and input, and the steps of manual measurement of the actual wear amount can specifically include:

[0119] ① Determine the installed inner diameter of the new connecting rod bearing 21;

[0120] Using a measuring tool, measure the inner diameter after installing at least one pair of new connecting rod bearings 21. It can be understood that determining the installed inner diameter of the new connecting rod bearing 21 is equivalent to choosing the measurement time when the connecting rod bearing 21 is replaced with a new spare part, so there is no need to disassemble the connecting rod power assembly specifically; of course, it is also feasible to determine the inner diameter of the already installed connecting rod bearing 21. In addition, the inner diameters of eighteen connecting rod bearings 21 can be measured separately to improve the accuracy of wear coefficient calibration.

[0121] ② Determine the running time and running conditions;

[0122] After running for a period of time, determine the working condition duration of the measured connecting rod bearing 21.

[0123] ③ Determine the wear depth of the bearing;

[0124] Disassemble the connecting rod power assembly and measure the inner diameter of the connecting rod bearing 21 again; then, according to the inner diameters of the connecting rod bearing 21 measured successively, an actual wear amount can be obtained.

[0125] Preferably, multiple points can be measured at different positions of the connecting rod bearing 21 to obtain the wear distribution, and the position with the most severe wear can be selected as the position finally used to calculate the actual wear amount.

[0126] S322: Input the first working condition duration and the second working condition duration into the dynamic calculation model respectively to obtain the slip distance and contact pressure of the crankshaft and the connecting rod bearing 21 under the periodic test condition and the rated operation condition.

[0127] It can be understood that the slip distance refers to the relative sliding distance between the connecting rod bearing 21 and the crankshaft. The contact pressure refers to the pressure per unit area between the connecting rod bearing 21 and the crankshaft. Secondly, the slip distance and contact pressure between the crankshaft and the connecting rod bearing 21 can be obtained by simulating the operation of the connecting rod dynamics calculation model for a preset time.

[0128] S323: According to the actual wear amounts under at least two different preset time periods, combined with the slip distance and contact pressure of the crankshaft and the connecting rod bearing 21 under the periodic test condition and the rated operation condition, obtain the third wear coefficient of the connecting rod bearing 21 under the periodic test condition and the fourth wear coefficient of the connecting rod bearing 21 under the rated operation condition.

[0129] It can be understood that the wear depth of the connecting rod bearing 21 is based on the data obtained under the total time of the first working condition duration and the second working condition duration, but the wear conditions under the first working condition duration and the second working condition duration cannot be directly determined. Therefore, the third wear coefficient and the fourth wear coefficient can be obtained by measuring the data under different time periods.

[0130] Specifically, substitute the obtained parameters into the above wear amount calculation formula to obtain at least two equations, and then solve the equations to obtain the third wear coefficient and the fourth wear coefficient.

[0131] Any equation can be expressed as:

[0132] h i =k3p i (t1)v i (t1)+k4p i (t2)v i (t2)

[0133] Wherein, k3 is the third wear coefficient, k4 is the fourth wear coefficient, p i (t1) is the contact pressure under the first working condition duration in any preset time period, v i (t1) is the contact pressure under the first working condition duration in any preset time period, p i (t2) is the contact pressure under the second working condition duration in any preset time period, v i(t2) is the contact pressure under the second working condition duration in any preset time period.

[0134] In addition, the present invention also constructs a reliability test device for an emergency diesel engine in a nuclear power plant, the device comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor; and the computer program is configured to implement the steps of the reliability test method for the emergency diesel engine in the nuclear power plant as described above.

[0135] The present invention also constructs a computer-readable storage medium storing a computer program, which when executed by a processor, implements the reliability test method for the emergency diesel engine in the nuclear power plant as described above.

[0136] It can be understood that the above embodiments only represent the preferred embodiments of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention; it should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can also be made, all of which fall within the protection scope of the present invention; therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. A reliability test method for an emergency diesel engine in a nuclear power plant, characterized in that, Including the following steps: S1: Obtain the operating condition information of the emergency diesel engine, and based on the operating condition information, obtain the estimated total service life of the parts of the connecting rod power assembly of the emergency diesel engine; S2: Obtain the structural information of the connecting rod power assembly, and based on the structural information and the operating condition information, construct a dynamic calculation model of the connecting rod power assembly, which is used to simulate the operation of the connecting rod power assembly at a preset time; S3: Obtain the wear coefficient of the parts, and input the wear coefficient and the estimated total service life into the dynamic calculation model to obtain the part wear amount; S4: Determine the reliability of the emergency diesel engine according to the part wear amount.

2. The reliability test method of the emergency diesel engine of a nuclear power plant according to claim 1, characterized in that Step S2 includes the following sub-steps: S21: Obtain the structural information of the connecting rod power assembly, and construct a three-dimensional geometric model of the connecting rod power assembly according to the structural information; S22: Based on the three-dimensional geometric model, combine the performance parameters, fluid parameters and state parameters in the operating condition information to construct a dynamic calculation model of the connecting rod power assembly.

3. The reliability test method for the emergency diesel engine of a nuclear power plant according to claim 2, characterized in that The fluid parameter includes the lubricating oil inlet pressure of the connecting rod power assembly, and the lubricating oil inlet pressure is the lubricating oil inlet pressure of the cylinder at the end of the lubricating oil flow direction in the emergency diesel engine.

4. The reliability test method for the emergency diesel engine of a nuclear power plant according to claim 1, characterized in that, The calculation formula for the part wear amount in the dynamic calculation model is expressed as: Where h i is the total wear of the i-th surface node in the part within one working cycle, t0 is the time of one working cycle, k is the wear coefficient, p i (t) is the contact pressure at the i-th surface node of the part at time t, v i (t) is the relative velocity between the i-th surface node of the part at time t and another part that mates with it.

5. The reliability test method for the emergency diesel engine of a nuclear power plant according to claim 1, characterized in that, The part includes a cylinder liner; the part wear amount includes the cylinder liner wear amount; The reliability test method for the emergency diesel engine of the nuclear power plant further includes a calibration step for the wear coefficient of the cylinder liner. The steps are specifically as follows: S311: Construct a calibration model, which is used to simulate the operation of the connecting rod power assembly; S312: Obtain friction experiment data, which are the data obtained from the friction experiment between the experimental cylinder liner and the experimental piston ring; and based on the friction experiment data, obtain the operating parameters for inputting into the calibration model; S313: Input the operating parameters and the preset wear coefficient into the calibration model to obtain the simulated wear amount; S314: Judge whether the difference between the simulated wear amount and the actual wear amount in the friction experiment data is within a preset range. If so, use the preset wear coefficient as the final wear coefficient for calculating the cylinder liner wear amount. If not, adjust the preset wear coefficient until the difference between the simulated wear amount and the actual wear amount is within the preset range.

6. The reliability test method for the emergency diesel engine of a nuclear power plant according to claim 5, characterized in that, Step S312 includes the following sub-steps: S3121: Obtain the friction experiment data, which includes the stroke and frequency of the friction specimen, and the contact load and contact area between the experimental cylinder liner and the experimental piston ring; S3122: Obtain the specific pressure according to the contact load and contact area; S3123: Obtain the average linear velocity according to the stroke and frequency; S3124: Obtain the calibrated cylinder pressure value according to the specific pressure, and obtain the calibrated rotational speed and calibrated stroke according to the average linear velocity; Step S313 is specifically: Input the calibrated cylinder pressure value, the calibrated rotational speed, the calibrated stroke, and a preset wear coefficient into the calibration model to obtain the simulated wear amount.

7. The reliability test method of the emergency diesel engine of a nuclear power plant according to claim 6, characterized in that, The estimated total service life of the cylinder liner includes the total duration of the cylinder liner under the periodic test conditions and the rated operating conditions; the friction experiment data includes lean oil lubrication friction experiment data and oil lubrication friction experiment data; In the calibration step of the wear coefficient of the cylinder liner, according to the lean oil lubrication friction experiment data, obtain the first wear coefficient of the cylinder liner corresponding to the periodic test conditions, and according to the oil lubrication friction experiment data, obtain the second wear coefficient of the cylinder liner corresponding to the rated operating conditions; In step S3, according to the first wear coefficient and the duration of the periodic test conditions of the cylinder liner, and the second wear coefficient and the duration of the rated operating conditions of the cylinder liner, obtain the wear amount of the cylinder liner.

8. The reliability test method for the emergency diesel engine of a nuclear power plant according to any one of claims 1-6, characterized in that, The part includes a connecting rod bearing; the estimated total service life of the connecting rod bearing includes the total duration of the connecting rod bearing under the periodic test conditions and the rated operating conditions; The reliability test method of the emergency diesel engine of the nuclear power plant further includes a calibration step of the wear coefficient of the connecting rod bearing, and the steps specifically include: S321: Obtain the actual wear amount of the connecting rod bearing under at least two different preset time periods; any one of the preset time periods includes the working duration of the connecting rod bearing under the periodic test conditions and the rated operating conditions; S322: Input the duration of the periodic test conditions and the duration of the rated operating conditions of the connecting rod bearing in each preset time period into the dynamic calculation model respectively to obtain the slip distance and contact pressure of the crankshaft of the connecting rod bearing and the connecting rod power assembly under the periodic test conditions and the rated operating conditions; S323: According to the actual wear amount under the at least two different preset time periods, combine the slip distance and contact pressure of the crankshaft and the connecting rod bearing under the periodic test conditions and the rated operating conditions to obtain the third wear coefficient of the connecting rod bearing under the periodic test conditions and the fourth wear coefficient of the connecting rod bearing under the rated operating conditions; In step S3, according to the third wear coefficient and the duration of the periodic test conditions of the connecting rod bearing, and the fourth wear coefficient and the duration of the rated operating conditions of the connecting rod bearing, obtain the wear amount of the connecting rod bearing.

9. A reliability test device for an emergency diesel engine of a nuclear power plant, the device comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the computer program is configured to implement the steps of the reliability test method of the emergency diesel engine of the nuclear power plant according to any one of claims 1-8.

10. A computer-readable storage medium stores a computer program, characterized in that, When the computer program is executed by the processor, it implements the reliability test method of the emergency diesel engine of the nuclear power plant according to any one of claims 1-8.

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