Since the introduction of the 600MW steam turbine of Harbin Electric Machinery Co., Ltd., it has produced 2 inspection units following the design of the Westinghouse Company in the United States, and then produced optimized models. The radial bearing adopts the tilting pad bearing. Because the bearing stability is good, the calculation and development work has not been carried out. In this paper, for the bearing loss of 600MW unit, the finite element method is used to calculate and analyze the bearing. In this way, the design can be optimized in the design to effectively reduce the bearing loss.
Taking the Qinshan 650MW turbine generator bearing as an example, the loss was calculated, and the bearing power consumption was measured on the unit in February 2000 to verify the calculation procedure.
1.1 Calculation of the bearing loss of the tilting pad In the calculation of this program, it is assumed that the lubricating oil of the bearing is an incompressible Newtonian fluid, ignoring the weight of the oil layer and the inertial force at the start and the pressure gradient in the direction of the thickness of the oil film, laminar or turbulent flow. In other cases, the journal and the bearing bush are not deformed.
In the theory of fluid lubrication, Reynolds equation describes the working process of radial sliding bearing, which comprehensively expresses the complexity of oil film pressure, lubricating oil viscosity, journal speed and bearing structural parameters (shaft diameter, bearing width, radius gap). The relationship between the bearing performance and the bearing performance calculation is based on the specific geometric parameters and operating conditions of the bearing. The two-dimensional Reynolds equation is solved by the finite element method to obtain the static and dynamic characteristic parameters of the bearing, ie the oil film pressure. Data such as power consumption, temperature rise, and lubricant flow. In the past, the dynamic and static characteristic program development of fixed-slide plain bearings was carried out, and the tilting pad bearing has more swings than the other fixed-tile bearings. Therefore, this factor should be considered in the equation of each tilting pad bearing.
The dimensionless oil film thickness of the tilting pad bearing is: When the constant is constant, the Reynolds equation for the static characteristic is: 13 The expression of the moment on the axis of the torque balance equation against the fulcrum can be written as: 1.1.4 Carrying capacity 1.1 .5 Frictional resistance The shear stress on the journal surface is: frictional resistance: (resistance = hand LXIf - Bu = = R2 is the relative unit of resistance, then the dimensionless resistance equation: if the oil film is broken, the frictional resistance is as follows: , 'is the working length of the tile; (is the diameter of the arc in the tile; the radius of the journal; the gap of the tile radius, the machining gap; 'the radius of the radius of the fulcrum; the eccentricity of the bearing; the gap of the radius of the phase tile Eccentricity rate
Since the tilting bush bearings are in steady state operation, the bearing bushes are in equilibrium, so the equations (2) and ST=0 should be connected in the calculation to solve the pressure distribution of each tile, the swing angle of each tile and the bearing load of each bearing. The coefficient, so that in the differential iterative solution, not only the offset angle, but also the swing angle.
The deviation angle correction and the swing angle correction can be converged by the dichotomy. The correction amount of the deviation angle is: consumption. The calculation formula is as follows: C lubricating oil specific heat, /kg p lubricating oil density, kg/m3; -T temperature rise, 6AT=T=ut-Tm, T=ut is the oil temperature, and Tin is the oil inlet temperature.
1.2.2 Test of bearing loss The test method is to install the resistance thermometer of the measuring oil near the bearing at the bearing inlet and outlet of the generator, and the turbine flowmeter to measure the movement through the bearing under various working conditions. The oil quantity, the oil inlet temperature and the oil discharge temperature calculate the power consumption of the bearing under various working conditions.
The instrument used, the resistance thermometer, the indexing number Cu50, the precision of 000r/min, the inlet oil temperature is controlled at 40C, and the measurement is performed when the operation is stable. Average power consumption error calculation: The deviation angle correction formula is:, = 0 Sigi (01). , s (11) initial value of the swing angle: 1 in the calculation, the maximum swing angle of the bearing bush, the formula of the maximum swing angle of the bearing bush is: the measured average power consumption error is in the range of 4.1 kW. The angle of the line.
The correction formula of the swing angle is: 2 loss calculation and actual measurement 2.1 loss calculation The bearing is a three-watt block type tilting pad bearing, the upper tile is fixed, the circumferential groove is opened, and the lower two tiles are tilting tiles. The structural dimensions are shown in Table 1. Table 1 Bearing structure parameter name Value Bearing load / L318500 journal speed / min-13000 journal diameter / mm500 bearing length to diameter ratio 0.812 bearing average specific pressure / MPa 0.16 clearance ratio 0.0021 bearing tile number / The block 3 watt block angle / °75 adjacent two watt fulcrum / ° 135 http:// in determining the direction and step size of the swing angle, but also as a criterion to determine whether the bearing pad reaches the equilibrium position.
1.2 Bearing loss test 1.2.1 Test principle It is assumed that the heat generated by the frictional power consumption in the bearing is completely taken away by the lubricating oil, ignoring the heat transferred by the heat conduction and the heat radiation. This test measures the flow rate of the lubricating oil of the bearing and the temperature of the oil entering and discharging. According to the flow rate and temperature rise of the lubricating oil, it is determined that the friction of the bearing is strongly supported. The municipal construction committee will come forward, and the municipal leadership will be the commanding director and organize the telecommunications. Various municipal departments such as gas, water, traffic control, etc., contributed to the project, and it took 3 months to complete the 'four-way cable tunnel' with a length of 1000m in the center of the old city. This completely solved the problem of high-pressure access to the city. At the same time, it also filled the blank of Wuhan in this field. However, due to the narrowness of the power sector's own plan, the newly completed tunnel pavement still has a 10kV overhead line, which is a comprehensive environmental improvement of the city. regret.
3 Urban power grid renovation plan In summary, the urban network transformation of the old city is imperative. The best way is that the power sector relies on the local government to formulate the development plan of the system according to the local master plan. Comprehensive management should be adopted. It should not only focus on the professional transformation within the system, but separate it from the local planning and construction, so that it does not match the behavior of the government, ignoring the factors that can be utilized in the surrounding area, and at the same time, causing undue The mutual restraint also slowed down the pace of urban network transformation. In the future renovation plan, the power sector should also separately list a plan to obtain funds to cope with the comprehensive rectification of the city. In a variety of ways, multiple channels, seize opportunities, and use all available power to make the city The network transformation funds will exert the greatest effect, improve the power grid construction as soon as possible, and optimize the power grid structure.
To solve the problem of insufficient funds for power construction, the key is that the power sector should emancipate the mind, change the concept, multi-market, multi-channel, multi-modal financing, and constantly expand the source of funds. First of all, we must pay full attention to the development of the power investment market and form diversified investments in the government, enterprises, and domestic and foreign markets. Second, expand channels, achieve multiple ways of financing, and focus on private capital and capital operations. Third, adopt a guiding role of policy and regulation. Fourth, reorganize and revitalize existing assets, and realize rapid turnover of funds through equity transfer, asset sales, and asset replacement.
As a government planning department, we should pay attention to cooperation with the power sector, truly achieve information sharing, unified planning, and reduce duplication of investment and redundant construction. As a power management department, under the principle of multi-party construction and unified management, we should also focus on macro-control in policies and regulations, and encourage enterprises to actively participate in infrastructure construction to reduce the pressure on urban network reconstruction and construction.
4 Conclusion In summary, urban construction planning is first. “The development of modern cities is inseparable from scientific urban planning and management. Perfect and strong infrastructure is an important guarantee for urban development. To comprehensively improve the quality of power supply in urban power supply networks, we must pay attention to The power construction of the old city will complete the thorough transformation of the old city power grid in the shortest possible time, and welcome the new round of economic tide with a new look. Under the existing conditions, strengthen the planning and construction of the urban power system, It is necessary to realize the capitalization and marketization of urban power grid construction. Only in this way can we adapt to the challenges of the knowledge economy and adapt to the requirements of the rapid development of cities in the 21st century.
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