Non-failure operation and diagnostics of Gas-Turbine

Summary

      In the monograph problems of non-failure operation gas-turbine power installations in operation and problems of their parametrical diagnosing are considered. Techniques of calculation of parameters of non-failure operation of installations while in service, and also procedures of diagnosing on the basis of the forecast of trends and the multivariate statistical analysis of parameters are resulted. Feature of a statement of the specified questions is wide use of modern information technologies on the basis of integrated mathematical packages Mathcad and Statistica. Examples of use of settlement techniques for the decision of practical problems of parametrical diagnosing on the basis of the analysis of operational data are given. The technique of an estimation of quality of test systems at a design stage of installations and in operation is offered.
      The monograph is calculated on experts of the scientific organizations, post-graduate students and students of the senior rates trained and solving practical problems of an estimation of a technical condition of complex objects in operation. Many sections of the monograph can be useful to design-engineers of gas-turbine power installations and also to the mechanical engineers maintaining installations.

Introduction

The world power in end of XX century has collided with necessity to learn to create rather inexpensive machines with the high technical and perfect eco-logical parameters. This need is mainly caused by an approaching deficiency of organic fuel, and also toughening of requirements to a level of environmental contamination.
      The analysis of tendencies of development of power machines testify that the most perfect installations can be created with use gas-turbine technologies. Many power experts well-earned consider XXI century - as a century of gas-turbine technologies.
      This opinion is based on:
   -  High power consumption of gas-turbine installations that is characterized by specific capacity 1-3 MW/m3 (1-2 MW/t) and significant modular capacity (10 - 800 MW);
   -  High efficiency on modes of a rated load (55 - 60 % and more in complex and binary cycles);
   -  High maneuverability and readiness for action (emergency preparation for action of 20-30 mines, time of start of 5-10 mines, time of an output for a nominal mode of 15-20 mines);
   -  High automation of managerial processes, small labor input of maintenance service, high maintainability.
   -  Power programs of industrially developed countries of the world at the end of XX century and at first half of XXI century confirm the tendency of wide use of gas-turbine installations for development of energy.
   -  In the middle of the last century significant successes in development of gas-turbine engines in military aircraft have been reached. It was caused both political opposition of two world systems, and struggle for development of gas-turbine technologies testifying to a level of development of technical potential of the countries.
   -  Four countries took part in development and creation gas-turbine engines of the third generation: the USSR, the USA, France, England; engines of the fourth generation - only three, and engines of the fifth generation - only two: Russia and the USA.
   -  Works on creation of engines of the sixth generation have started only in the USA. It speaks that expenses for creation of engines of "new generation" are very great. However these expenses are justified by that gas-turbine technolo-gies become a basis of the further development of the industry of the advanced industrial countries of the world the nearest 50 years.
   -  It is known, that industrial application of gas turbines has begun with con-version aviation gas-turbine engines, but now industrial gas-turbine equipment all over the world develops more intensively. It has led to that working off of the most advanced gas-turbine technologies frequently advances development of aviation engines, being base already for perfection of aircraft.
   -  In 1992 in the USA the program "Advanced Turbine System" (ATS) with the purpose of creation gas-turbine installations with efficiency of a simple cycle of 40 %, in the combined cycle - 60 % has been accepted; decrease in issue NOx to a level no more than 9 m, and CO - no more than 20 m behind the free turbine without external systems of suppression of harmful emissions at preser-vation or increase of a level of reliability. The last years have shown that this pro-gram in many respects is executed.
   -  In the world power market companies GE, Rolls-Royce, ABB, Siemens, Solar Turbines, Mitsubishi Heavy Industries Europe and a number of other firms are widely presented. More than 40 years in the world market of industrial gas turbines are in the lead company General Electric Power Systems (nearby 50 % of the world market of gas turbines).
   -  Many transnational companies get in the gas-turbine industry of the Rus-sian Federation buying shares of leading engine building firms. So, for example, Pratt and Whitney company, the recognized manufacturer of aviation engines, has got a share holding of one of leading Russian enterprises of Open Share So-ciety "Permskie motory", and firm Siemens - shares of "Silovie machiny". The big contribution to development gas-turbine power domestic aviation design of-fices and manufactures "Saturn", "B named N.D. Kuznetsov", etc.
   -  As a whole all the firms developing the advanced gas turbines, distin-guishes aspiration to raise characteristics of engines due to improvement of loop variables, developments of technologies of burning for decrease in issue nitro-gen and carbon oxid, to apply alternative kinds of fuel, to introduce programs of improvement of already created production.
   -  Realization of these efforts can be tracked on change of key parameters of gas-turbine installations: temperature of gases after the chamber of combus-tion and a degree of increase of pressure. These parameters from year to year grow, providing with that high profitability of installations.
   -  Development of gas-turbine installations goes not only on a way of in-crease of profitability, but also increase in their reliability.
   -  For realization in concrete engines and installations of these tendencies at all stages of development of gas-turbine installations it was necessary to solve challenges of their designing, creation and operation. These problems arise and at designing of gas-turbine installations, for example, when it is required to pro-vide the set durability of hot details (50?100 thousand hours) at high tempera-tures (1200 and more) and pressure of gas (up to 3,0 P), and also at fre-quencies of rotation of rotors of 150-300 Hz.
   -  If to consider thus loadings on rotating details from the centrifugal forces, bending forces of gas pressure, and also cyclic thermal loadings and an excited environment of cyclic air it becomes clear, how much the challenge faces by de-sign-engineers at a choice of materials, calculations on durability of details and at a choice of optimum schemes and corresponding parameters of installations.
   -  It is necessary to expect, that in the near future at designing following perspective decisions will be realized:
  1.  The Technology of volumetric computer designing blades and steps of compressors will allow to reach high degrees of increase of pressure in one step (up to 3,5).
  2. Improvement of condensation will allow to reduce sharply outflow of a working body and to raise efficiency.
  3.  Creation of new materials and sheetings will remove limits of high-temperature corrosion of metals.
  4. New technologies of cooling of hot details (for example, cooling blades turbines by the steam) will allow to create turbines with temperature of gas nearby 2000 .
  5.  Heats of gas in the turbine now are provided monocrystal blades, sheetings and corresponding systems of cooling. It is known, that if from a cycle are selected more than 8 % of the general charge of air advantages from rise in temperature of gas are lost all. Steam cooling is considered the most perspective as the temperature of air after the compressor can reach 850 that demands its additional cooling before submission in cooling channels of turbines. Steam cool-ing is especially convenient in the combined installations where steam is used as a working body. Injection only 5 % of steam to air gives as a result of 12 % of ad-ditional energy. At the same time at submission of steam in chamber of combus-tion decreases throughput of the turbine and decrease in a stock of stability of the compressor is possible.
     Except for sheetings known now - thermobarrierical on the basis of ZrO2-Y2O3 thickness 100-300 microns, diffusional and plasma - are developed new aliteration coverings by thickness 25-75 microns with addition of platinum that in-creases stability corrosion.
  6.  Introduction of dry chambers of combustion, liquidation of a problem of the vibrating burning, new technologies of burning will allow to receive NOx < 9 ppm. It will demand increase in number of atomizers at 5-10 times. Their number can reach 200 pieces, located by three rings which are connected in process of output in gas-turbine installations on full capacity. Accordingly, the system of automatic control on modes of the lowered capacity becomes compli-cated. The factor of surplus of air in a zone of burning will increase up to three. Constant ignition of fuel will be provided with an on duty constantly working atom-izer with the small charge of fuel, instead of air circulation as it was done earlier. In gas-turbine installations ring chambers of combustion will be mainly applied. However in such chambers of combustion for reduction of an output of other harmful impurity (CO2, CO, not burned down hydrocarbons) the long chamber of mixture and a heat that contradicts the previous constructive decisions are re-quired.
  7.  Perspective control systems will be based on new devices and means of the control: pyrometers for measurement of temperature of metal, instead of gas; gauges of dynamic pressure for registration of pulsations of a stream in the compressor and in the chamber of combustion; accelerometers for definition of high-frequency fluctuations of blades and prevention of their destruction.
  8. The built in system of monitoring and diagnosing of parameters on the basis of neuronets technologies will provide prolongation of service life of gas-turbine installations, increase in a reserve maintenance period, economy of fuel.
  9. There Are certain problems in manufacture gas-turbine engines which are connected with manufacturing techniques and tests of separate details, units and units. Modern gas-turbine building is precision technologies of precision moulding with operated process of crystallization, electrochemical processing complex three-dimensional curvilinear surfaces, powder metallurgy and many other things. For decrease vibration loadings of details all rotors of engines are subjected to dynamic balancing on working frequencies of rotation that demands special power-intensive machine tools with computer management. Thermal processing of details and drawing of complex multicomponent sheetings (for example, Co-Cr-Al-Y) is an obligatory stage in technology of protection blades turbines from aggressive influence of products of combustion and impurity in cyclic air.
     Specific problems at creation effective gas-turbine installations arise dur-ing their tests and check of parameters of non-failure operation demanded by the customer and durability. Often at the stand it is impossible to reproduce all condi-tions of operation of installations in real conditions. Development of special pro-grams, for example, on the basis of methods of the equivalent accelerated tests therefore is required. For essentially new installations development of such pro-grams represents a challenge with low probability of their authentic decision.
     Development new gas-turbine installations with the raised parameters of a working body will inevitably demand at a new level to solve problems of their reliability. For last years reliability gas-turbine installations of various purpose constantly raised due to perfection of designs, application of new materials, im-provement of manufacturing techniques. However constantly growing require-ments to non-failure operation of installations, development of actions on a safety of objects of power cause to improve a quality monitoring and diagnostics for ac-cident precaution with heavy consequences.
      Development of effective test systems not only can raise non-failure op-eration of installations due to early detection of preconditions to refusals but also will give a significant economic gain at reduction of off-schedule idle times.
      Thus technical progress in the power connected with development gas-turbine technologies demands the complex (system) approach to the decision of problems of non-failure operation of created installations and their diagnosing while in service. Thus it is necessary to be guided both by requirements to devel-oped installations, and on operating experience already existing gas-turbine in-stallations.
      By development of a material of the present edition the author was based not only on personal operating experience gas-turbine installations, but also on the extensive literature on problems of reliability and diagnosing and also on im-pressions of dialogue with the visible expert in the field of reliability and the charming person professor I.A. Ryabinin. Certainly, the monograph could not arise without presence of fundamental preparation which was provided with fac-ulty of steam and gas turbines of the Naval academy.
      The structure of the monograph and its maintenance were influenced with discussion of many questions with colleagues of faculties of power installations of the Naval academy, heat power installations and thermal engines of the St.-Petersburg state technological university of plant polymers, ship turbines and turbine installations of the St.-Petersburg state sea technical university, gas-turbine installations of Naval engineering institute, for what the author is im-mensely grateful to them. The special gratitude to the colleague on faculty of academy, senior lecturer N.A. Marchukov who traditionally reads manuscripts of the author and does the important and valuable remarks not only substantial, but also stylistic character.
      Considering stated, the author will not be surprised, if the close reader will find out some advantages in this edition. At the same time, available lacks which the author completely carries on the account, can form the basis for the construc-tive criticism providing the further development of the important problems of maintenance of non-failure operation of complex technical objects.


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