Specific Features of the Replacement of the Available Flow Path by the Optimal Flow Path when Upgrading the Steam Turbine High-Pressure Cylinder

This scientific paper gives the main research data obtained during the solution of the search problem to define optimal parameter values for the thermal circuit of the К-540-23.5 turbine unit that would provide the most efficient operation both for the optimal version of the high pressure cylinder (HPC) as part of the turbine unit and the turbine unit on the whole. The effect of the distribution of heat differences in the stages of the optimal flow part of the high pressure cylinder used by the К-540-23.5 turbine on the integral quality factors of the turbine unit has been assessed. The calculation studies of the thermal circuit of the turbine unit with the optimal flow section of the high-pressure cylinder showed that the temperature of the underheated feed water in the high pressure heater (HPH) arranged near the steam generator has the most critical effect on the power and economical efficiency of the high pressure cylinder and entire turbine unit. The two-criterion Pareto problem for the upgrading of the turbine unit was formulated and solved to define optimal underheating temperature values. Consideration was given to the two variants of the solution of the optimization problem for the feed water underheating temperature in the high pressure heater. Comparison and analysis of the two variants of solution for the two-criterion optimization problem showed the identity of the obtained data and it confirms the correctness of the problem formulation and the algorithms used for its solution.

Development of the flow part of reactive type HPC of K-325-23,5 series steam turbine based on the use of modern computer technologies

The results of gas-dynamic design of a new flow part of a reactive type high-pressure cylinder (HPC) of the K-300 series condensing steam turbine are presented. The turbine was developed using a comprehensive methodology implemented in the IPMFlow software package. The methodology includes gas-dynamic calculations of various levels of complexity, as well as methods for analytical construction of the spatial shape of the blade rows based on a limited number of parameterized values. The real thermodynamic properties of water and steam were taken into account in 3D calculations of turbulent flows. At the final stage, 3D end-to-end calculations of the HPC, which consists of 18 stages, were carried out. The technology of parallel computing was applied in the said calculations. It is shown that a significant increase in efficiency and power has been achieved in the developed HPC due to the use of reactive type stages with modern smooth blade profiles and monotonic meridional contours.

Research on Water Droplet Movement Characteristics in the Last Two Stages of Low-Pressure Cylinder of Steam Turbine Under Low Load Conditions

In the operating process of the coal-fired generation during flexible peaking regulation, the primary and secondary water droplets in the steam flowing through the last two stages of the low-pressure cylinder could influence the efficiency and safety of the steam turbine definitely. However, systematic analysis of the movement characteristics of water droplets under low-load conditions is scarcely in the existing research, especially the ultra-low load conditions below 30%. Toward this end, the more novel algebraic slip model and particle transport model mentioned in this paper are used to simulate the primary and secondary water droplets. Taking a 600 MW unit as a research object, the droplets motion characteristics of the last two stages were simulated within four load conditions, including 100, 50, 40, and 30% THA. The results show that the diameter of the primary water droplets is smaller, ranging from 0 to 1 µm, during the flexible peak regulation process of the steam turbine. The deposition is mainly located at the entire moving blades and the trailing edge of the last two stator blades. With the load decreasing, the deposition effect decreases sustainably. And the larger diameters of secondary water droplets range from 10 to 300 µm. The erosion of secondary water droplets in the last stage is more serious than that of the second last stage for different load conditions, and the erosion of the second last stage could be negligible. The pressure face and suction face at 30% blade height of the last stage blade have been eroded most seriously. The lower the load, the worse erosion from the secondary water droplets, which poses a potential threat to the fracture of the last stage blades of the steam turbine. This study provides a certain reference value for the optimal design of steam turbine blades under flexible peak regulation.

Research of the parameters of acoustic emission signals during the destruction of the liner material and the power shell of a metal-composite high-pressure cylinder

To The article provides information on the results of studying the parameters of acoustic emission signals during the destruction of the liner material and micro-plastic of the power shell of a metal-composite high-pressure cylinder. B-200 within the framework of a complex of studies to create an acoustic-emission portrait of metal-composite high-pressure cylinders. It was found that the most informative parameter when carrying out technical diagnostics of a liner is the signal amplitude recorded in the private range of 60-80 kHz, and a sign of microplastic rupture is the emission of acoustic emission signals reaching 82 dB.

IMPLEMENTATION OF QUALITY CONTROL IN NEWSPAPER PRINTING COMPANIES

Newspaper printing production processes cannot be separated from the problems that affect printed results and excessive waste. So in a printing company, quality control is needed in order to get good printing results and minimize the amount of waste. The print quality results in a company have several shortcomings such as unsuitable colors, and difficulty to get the register when printing. Apart from the aforementioned shortcomings, there are also factors that cause excessive waste, namely scumming, register disturbances, not sharp printouts, set-off, ghosting, and broken paper. How to solve problems that affect print quality and excess waste by cleaning the ink roll, adjusting the leg according to the proof, adjusting the pressure cylinder pressure, and adjusting the volume of wetting water. From the problems found, the print quality results in a printing company need to be increased so that the amount of waste generated is not too much or too much.Keywords— Print Quality, Waste, Quality Control

Investigation of the Thermal Strength of Steam Turbine Diaphragms with Reduction of Axial Dimensions

The problem of reducing the axial dimensions of steam turbine diaphragms is associated with the problem of steam turbine modernization performed by increasing the number of reactive blading stages and using existing foundations. Evaluation of the suitability of diaphragm design versions with established steam flow characteristics was carried out with constraints on short- and long-term strength conditions, as well as the accumulation of axial deflections due to creep. For computational research, there was introduced a methodology using the finite element method and Yu. M. Rabotnov’s theory of strain aging. The calculation of creep was reduced to solving an elastic-plastic problem with a deformation curve, which was represented by an isochronous creep curve for the time chosen. A software was used providing for the automated construction of the original computer diaphragm model with the help of guide-vane profile drawings and axial cross-sections of the diaphragm rim and body, as well as several geometric parameters. The calculated model of a welded diaphragm reproduces the main essential features of the structure, the material properties of its elements, as well as steam load. The exploratory studies of diaphragms with reduced axial dimensions were performed on the example of the second- and third-stage diaphragms of the high-pressure cylinder of the K-325-23.5 steam turbine. The original second- and third-stage diaphragm designs were considered to be basic, in relation to which, according to strength and rigidity parameters, the alternative ones were compared. Calculated data for the basic diaphragm design versions for 100 thousand operating hours were obtained. According to the calculations, maximum deflections are achieved at diaphragm edges, and the stresses, that are maximum at the points where the guide vanes are attached to the diaphragm rim and body, undergo a significant redistribution due to creep. Two approaches to the reduction of the axial dimensions of the second-stage diaphragm design of the steam turbine high pressure cylinder were involved. In the first approach, the reduction of the dimensions was achieved by proportionally reducing the guide-vane profile with a corresponding increase in the number of the guide vanes. In the second approach, the profile remained unchanged, but the axial dimensions of the diaphragm rim and body were reduced. The parameters of strength both in the elastic state at the beginning of operation and in the conditions of creep, as well as the accumulation of axial deflections were investigated. Based on the comparisons with the basic design, it was established that the second approach is more effective. Additional recommendations for the use of more heat-resistant steels for outlet guide vanes and the conditions of diaphragm attachment in the turbine casing are given.

An adjustable parameter water hammer wave hose testbench

In this paper, based on the servo valve controlled pressure cylinder, a scheme of hydraulic pipeline adjustable parameters water hammer wave test system is proposed. By changing the quality of pressure cylinder piston rod and controlling the opening of servo valve, the overshoot, pressure rise rate and oscillation of water hammer wave can be controlled. On this basis, based on AMESim simulation software, the paper studies the influence of different parameters of pressure cylinder and servo valve on water hammer wave, which provides the basis for the selection of main components. Finally, the experimental research is carried out on the designed system, and the results are consistent with the simulation results. The generated water hammer wave meets the requirements of the test standard, which proves that the hydraulic adjustable parameters water hammer test system developed in this paper is successful and feasible.