The thermo-stressed state of steam turbine rotors during plant start-up

This article suggests the use of the value of the thermo-stressed state in the turbine steam input stage as one of the key parameters characterizing the start-up reliability of the turbine plant cycle. The authors present the principles of the development of the steam turbine rotor warming model for continuous monitoring of its thermo-stressed state, using a personal computer in real time. The research conducted on the thermo-stressed state of the rotor using a universal CAE programme allowed the hypothesizing of the maximum thermo-stressed states as can be calculated with sufficient precision by ‘characteristic’ temperature differences inside the rotor. It is proposed to evaluate the thermo-stressed states using regression dependence on the ‘characteristic’ differences of the real-time temperature field. Samples for the regression analysis are obtained from preliminary results of CAE programme calculations. An example is given for the whole range of the necessary computational research to produce modules of a control device for the steam turbine T-110/120-130. The modules are tested in the MATLAB Simulink environment

Effect of steam addition on gas turbine combustor design and performance

Adding steam influences the combustion process inside the combustor, which should be taken into account during combustor design. The design of combustor has long been the most challenging process. This study integrated the gas turbine performance with the combustor design, and formulated a detailed procedure for single annular combustors with steam addition consideration in particular. To accomplish this, a computer code has been developed based on the design procedures. The design model could provide the combustor geometry and the combustor performance. The inlet parameters for combustor design are obtained and validated through the calculation of gas turbine engine performance provided by our own home code. The model predictions are compared with operational and configuration data from two real engines and show reasonably good accuracy. The influence of steam addition on combustor design is investigated and results showed the variation of geometrical size is highest for components where intense combustion takes place while the design is almost kept the same for components where only pure flow exists. After conforming the feasibility of the combustor design code, we investigated the effects of steam addition on combustor performance. It revealed that steam injection is an effective way to reduce the temperature in the burner while other performance like the total pressure loss would be slightly deteriorated

Numerical Research of Steam and Gas Plant Efficiency of Triple Cycle for Extreme North Regions

The present work shows that temperature decrease of heat rejection in a cycle is necessary for energy efficiency of steam turbine plants. Minimum temperature of heat rejection at steam turbine plant work on water steam is 15°C. Steam turbine plant of triple cycle where lower cycle of steam turbine plant is organic Rankine cycle on low-boiling substance with heat rejection in air condenser, which safely allows rejecting heat at condensation temperatures below 0°C, has been offered. Mathematical model of steam and gas plant of triple cycle, which allows conducting complex researches with change of working body appearance and parameters defining thermodynamic efficiency of cycles, has been developed. On the basis of the model a program of parameters and index cycles design of steam and gas plants has been developed in a package of electron tables Excel. Numerical studies of models showed that energy efficiency of steam turbine plants of triple cycle strongly depend on low-boiling substance type in a lower cycle. Energy efficiency of steam and gas plants net 60% higher can be received for steam and gas plants on the basis of gas turbine plant NK-36ST on pentane and its condensation temperature below 0°C. It was stated that energy efficiency of steam and gas plants net linearly depends on condensation temperature of low-boiling substance type and temperature of gases leaving reco very boiler. Energy efficiency increases by 1% at 10% decrease of condensation temperature of pentane, and it increases by 0.88% at 15°C temperature decrease of gases leaving recovery boiler

Numerical Research of Steam and Gas Plant Efficiency of Triple Cycle for Extreme North Regions

The present work shows that temperature decrease of heat rejection in a cycle is necessary for energy efficiency of steam turbine plants. Minimum temperature of heat rejection at steam turbine plant work on water steam is 15°C. Steam turbine plant of triple cycle where lower cycle of steam turbine plant is organic Rankine cycle on low-boiling substance with heat rejection in air condenser, which safely allows rejecting heat at condensation temperatures below 0°C, has been offered. Mathematical model of steam and gas plant of triple cycle, which allows conducting complex researches with change of working body appearance and parameters defining thermodynamic efficiency of cycles, has been developed. On the basis of the model a program of parameters and index cycles design of steam and gas plants has been developed in a package of electron tables Excel. Numerical studies of models showed that energy efficiency of steam turbine plants of triple cycle strongly depend on low-boiling substance type in a lower cycle. Energy efficiency of steam and gas plants net 60% higher can be received for steam and gas plants on the basis of gas turbine plant NK-36ST on pentane and its condensation temperature below 0°C. It was stated that energy efficiency of steam and gas plants net linearly depends on condensation temperature of low-boiling substance type and temperature of gases leaving reco very boiler. Energy efficiency increases by 1% at 10% decrease of condensation temperature of pentane, and it increases by 0.88% at 15°C temperature decrease of gases leaving recovery boiler

Fatigue life prediction of mistuned steam turbine blades subjected to deviations in blade geometry

The blades of the steam turbine are subjected to bending of the steam flow, centrifugal loading, vibration response, and structural mistuning. These factors mentioned contribute significantly to the fatigue failure of steam turbine blades. Low pressure (LP) steam turbines experience premature blade and disk failures due to the stress concentrations in the root location of the blade of its bladed disk. This study of mistuned steam turbine blades subjected to variation in blade geometry will be of great significance to the electricity generation industry. A simplified, mistuned, scaled-down steam turbine bladed disk model was developed using ABAQUS finite element analysis (FEA) software. The acquisition of the vibration characteristics and steady-state stress response of the disk models was carried out through FEA. Such studies are very limited. Subsequently, numerical stress distributions were acquired and the model was subsequently exported to Fe-Safe software for fatigue life calculations based on centrifugal and harmonic sinusoidal pressure loading. Vibration characteristics and response of the variation of the geometric blade of the steam turbine were investigated. Natural FEA frequencies compared well with the published literature of real steam turbines, indicating the reliability of the developed FEA model. The study found that fatigue life is most sensitive to changes in blade length, followed by width and then thickness, in this order. Analytical life cycles and Fe-Safe software show a percentage difference of less than 4.86%. This concludes that the numerical methodology developed can be used for real-life mistuned steam turbine blades subjected to variations in blade geometry

Model of steam turbine K-1000-60/1500-2 for control processes research

Приведены уравнения переходных режимов паровой турбины. Путем преобразования уравнений турбины построена нелинейная модель паровой турбины К-1000-60/1500-2 как объекта автоматического управления в относительных переменных состояния, учитывающая экспериментальные данные регулирующих органов и использующая минимальное количество вычислений. На основании этой модели для исследования режима сброса нагрузки построены графики изменения переменных давления и частоты.Presentation of model of steam turbine К-1000-60/1500-2 in the state space of relative variables is the aim of the article. Using the physics laws equations describing the dynamics of NPP steam turbine as an automation object in variable modes are considered. By transforming the equations of the dynamics nonlinear model of the steam turbine in relative state variables is built as a system of differential equations in the Cauchy form. The model takes into account the experimental data of regulators and uses a minimal amount of computations. Graphs of nonlinear functions of flow coefficients of the variables of servomotors coordinate values of the control valve and control flap, derived from the experimental data, are constructed. Formulas for the calculation and the calculated values of the constants parameters of the model are given. The input variables of the model are the coordinates of the servomotors of control valve and control flaps, as well as the power of the electric generator. On the basis of the turbine model for the study of the load shedding mode of electric generator graphs of pressure variables in steam volumes and speed of the rotor are constructed by numerical integration of the differential equations system for given functions of closing of servomotors of control valve and control flap. The maximum casting speed of turbine rotor is 7.36 % of the nominal frequency value. Similarly, nonlinear model of a steam turbine K-1000-60/1500-2 can be obtained. Models nuclear steam turbines in relative variables with the minimum number of calculations can be used to optimize the control system parameters of the steam turbine of nuclear power plant

Steam storage systems for flexible biomass CHP plants - Evaluation and initial model based calculation

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Within the present study a novel concept for the demand-oriented power generation of a solid-biomass fueled combined heat and power (CHP) plant is investigated. The integration of a steam storage system into the plants process enables a decoupling of the steam (boiler) and the power generation (steam turbine). By buffering the steam, the power output of the turbine can be adjusted without changing the rated thermal capacity of the plant. Various available storage systems are selected and comparatively evaluated applying the adapted analytic hierarchy process (AHP). The technology assessment revealed that the combination of a steam accumulator and solid concrete storage represents the best suiting option. An initial model based simulation study is performed to identify the fundamental behaviour of this system, integrated in a biomass CHP plant. The operation principle is has proved their technical feasibility and seems to be applicable at a commercial scale. According to the modelling results flexible short term power generation in a time range of up to fifteen minutes is applicable. A load-range of almost the plants rated capacity can be achieved

Effect of Increasing Sea Water Temperature on Performance of Steam Turbine of Muara Tawar Power Plant

Muara Tawar Power Plant is located on the coast of Bekasi, West Java, Indonesia. Along with the economic development, there are plans to do reclamation the sea around Muara Tawar Power Plant and build around it as a port and industrial estate. This could potentially lead to an increase in sea water temperatures. This paper aims to determine the effect of increasing sea water temperature on the performance of steam turbine 1.4 in Muara Tawar Power Plant, which uses sea water as a condenser cooling medium. The intended performance is the output power of the steam turbine, the condenser pressure and the system efficiency. Steam turbine 1.4 has 225 MW installed output power, supplied from 3 HRSG (Heat Recovery Steam Generator).Analysis of the effect of sea water temperature rise on steam turbine performance is carried out by using the cycle-tempo software. The main equipment of steam turbine is modeled in cycle-tempo, then model is validated by comparing with design data. Varies sea water temperature then is inputted on model in order to obtain the output power of steam turbine, condenser pressure and system efficiency. The results show that for every 1˚C increase in condenser cooling water temperature extracted from seawater near the plant, the output power of the plant decreased by about 0.171%, the condenser pressure increased by about 5.146%, and the system efficiency decreased by about 0.168%

A Parametric Investigation of the Steam Injection Gas Turbine System on a Cogeneration Plant

The aim of this study is to conduct a parametric investigation of the steam injection gas turbine system by focusing on the effect of the steam mass flow rate on the energy transfer behaviors of a cogeneration plant.  A thermodynamic model of two gas turbine cycles and one steam turbine cycle and a heat transfer model of the heat recovery steam generator are developed.  A successive iteration is employed to solve a set of equations and obtain a converged solution.  The result shows that by increasing the mass flow rate for the steam injection gas turbine system from 0 to 2 kg/s, the input energy rate from the fuel and the total electrical output power from the cogeneration plant are increased, resulting in an increase of the cogeneration electrical efficiency from 49.9% to 50.4%.  On the other hand, the output heat rate from the steam from the cogeneration plant is decreased, resulting in a decrease of the cogeneration heat efficiency from 8.5% to 5.4%.  Consequently, the primary energy saving of the cogeneration plant decreases from 16.6% to 14.9%.&nbsp

A Heat Balance Program for a Nuclear Power Plant

In a coal fired power plant, the steam leaving the boiler can reach 1000 °F and 3000 psia; this state is superheated considerably. On the other hand, a nuclear power plant is not capable of reaching such conditions without compromising reactor safety and integrity. Therefore, the steam leaving the reactor might only be a few degrees superheated, and hence the steam leaving each turbine will be wet. Since wet steam will erode turbine blades very quickly, devices must be placed between turbines to separate the steam into saturated vapor and saturated liquid. The steam is routed through the next turbine and the water is added elsewhere in the system (usually a feedwater heater, FH). This device is called a moisture separator, and my task was to add the FORTRAN code necessary to accurately model a moisture separator into an existing heat balance program