Research of Calculation Models for Exhaust Enthalpy of Steam Turbine

2012 ◽  
Vol 550-553 ◽  
pp. 3160-3163
Author(s):  
Yong Guang Ma ◽  
Ning Ran ◽  
Bing Zheng
Keyword(s):  
Energy Balance ◽  
Steam Turbine ◽  
Open System ◽  
Performance Monitoring ◽  
Thermal Power ◽  
Energy Balance Equation ◽  
Calculation Model ◽  
Power Generating Unit ◽  
Calculation Results ◽  
Unit Performance

For the low pressure (LP) cylinder of a steam turbine, computation of the exhaust enthalpy is an important part in thermal power generating unit performance monitoring. A new online model for calculating the exhaust enthalpy was proposed aiming at the limitation of existing online calculation model for calculating the enthalpy of steam turbine LP cylinder exhaust steam. This model treats LP cylinder, condenser and corresponding heater as an open system, according to the energy balance equation of this open system, figuring out its exhaust enthalpy. Calculation results of typical steam turbine show that: in a large load change range, the results are close to thermal experimental value, the accuracy is similar to energy balance method.

Transient Analysis for Effect of TDFWP on the Operation of Main Equipments in Direct Air-Cooled Thermal Power Generating Unit

2011 ◽  
Author(s):  
Chen Yang ◽  
Shengli Tang
Keyword(s):  
Steam Turbine ◽  
Water Flow ◽  
Transient Analysis ◽  
Thermal Power ◽  
Back Pressure ◽  
Feed Water ◽  
Feed Pump ◽  
Power Generating Unit ◽  
Main Steam ◽  
Water Pumps

For the air-cooled thermal power generating unit, specific climatic conditions exert fast and great impact on the condenser pressure. When equipping turbine driven feed water pumps (TDFWP), as the exhaust steam leaving the boiler feed pump turbine (BFPT) is directly discharged into the air-cooled system, the change of environmental conditions such as air temperature and wind speed will result in the distinct change of BFPT back-pressure both in scope and magnitude. For once-through boilers, such changes will cause disturbance to feed water, and further lead to the change of fuel and air feeding. The back-pressure of main steam turbine is much higher in summer climatic condition. In order to maintain rated or certain power load, steam supplied into the main steam turbine has to be increased. Meanwhile, it is necessary to increase the steam flux in the driving turbine to maintain the needed power for feed water pumps, so there is a conflict that the driving turbine for feed water pumps will compete for steam with the main steam turbine. A dynamical mathematical model of a 600MW direct air-cooled thermal power generating unit is built in this paper. The focus is on the transient analysis of the effect of TDFWP on main equipments when the back-pressure changes in the manners of slope and step mutations. Simulation results show that when the disturbance is smaller, the unit can be quickly adjusted to the operational status at given steam and feed water flow rates. The greater the magnate of back-pressure mutation, the greater the changing range of the parameters, and the longer time is needed for adjusting. Under the condition of the same change magnitude of back-pressure, when the back-pressure rise time is longer, the parameters fluctuation is smaller. When the disturbance is larger, the steam flow of TDFWP is gradually increased to its maximum value. With further increase in the back-pressure, the steam flux in the turbine of TDFWP is gradually decreased, so it is difficult to ensure the feed water flow in this case. The results in this study provide important theoretical significance and engineering reference for the implementation of utilizing direct cooling steam feed pump technology in the actual unit.

scholarly journals THE ALGORITHM OF ANALYSIS OF ENERGY EFFICIENCY OF HEAT SUPPLY SOURCE

2019 ◽  
pp. 54-62
Author(s):  
В. Буланин ◽  
V. Bulanin
Keyword(s):  
Energy Balance ◽  
Power Plant ◽  
Steam Turbine ◽  
Heat Supply ◽  
Power Plants ◽  
Thermal Power ◽  
Heat Supply System ◽  
Supply Source ◽  
The Impact ◽  
Turbine Installation

The main energy-consuming element of the heat supply system of cities and settlements is a source of heat energy. In connection with the need to minimize the cost of fuel and electricity for heat supply, the article presents an analysis of the energy balance of the steam turbine installation, on the basis of which new analytical expressions are developed that comprehensively characterize the efficiency of the power plant. In 2000 еру RD 153-34.1-09.163-00 "Model program of energy audits of thermal power plants and district boiler houses of joint-stock companies of power and electrification of Russia" was enacted. Some aspects of the analysis of the energy balance of the steam turbine installation using the relative increase in heat consumption for condensation power generation are considered. An analytical assessment of the impact of energy costs on the boiler unit's own needs on the energy balance of the thermal power plant is made.

Adaptation of Algorithms for Diagnostics of Steam Turbine Unit Equipment to Specific Conditions at Thermal Power Stations

2020 ◽  
Vol 67 (11) ◽  
pp. 800-804
Author(s):  
K. E. Aronson ◽  
B. E. Murmansky ◽  
V. B. Novoselov ◽  
Yu. M. Brodov ◽  
A. Yu. Sosnovsky ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Turbine Unit ◽  
Thermal Power ◽  
Steam Turbine Unit ◽  
Power Stations ◽  
Thermal Power Stations

Investigation on the Influence of Pressure Terms in a Volume-Averaged Energy Balance in the Modelling of Liquid Composite Moulding Processes

2019 ◽  
Vol 809 ◽  
pp. 480-486
Author(s):  
Rohit George Sebastian ◽  
Christof Obertscheider ◽  
Ewald Fauster ◽  
Ralf Schledjewski
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Energy Balance ◽  
Matrix Material ◽  
Energy Balance Equation ◽  
Manufacturing Processes ◽  
Composite Manufacturing ◽  
Liquid Composite Moulding ◽  
The Matrix ◽  
Computational Fluid Dynamics Cfd

The growing use of composite materials has generated interest in improving and optimising composite manufacturing processes such as Liquid Composite Moulding (LCM). In LCM, dry preforms are placed in a mould and impregnated with the matrix material. The efficiency of filling the moulds can be improved by using Computational Fluid Dynamics (CFD) filling simulations during the design of the mould. As part of an on-going effort to develop a CFD tool for the simulation of LCM processes, a volume averaged energy balance equation has been derived and implemented in a custom OpenFOAM solver. The energy balance is implemented in a custom OpenFOAM solver with and without the pressure terms for comparison with results from RTM experiments. It is found that the pressure terms do not significantly influence the results for LCM processes.

Variability in Thermal Performance and Measured Heat Rate in Fossil-Fuelled Power Plants

1992 ◽  
Vol 206 (2) ◽  
pp. 109-123 ◽  
Author(s):  
F L Carvalho ◽  
F H D Conradie ◽  
H Kuerten ◽  
F J McDyer
Keyword(s):  
Thermal Performance ◽  
Power Plants ◽  
Performance Monitoring ◽  
Unit Commitment ◽  
Thermal Power ◽  
Heat Rate ◽  
Plant Performance ◽  
Plant Management ◽  
Fuel Quality ◽  
Stable Operating

The paper examines the variability of key parameters in the operation of ten thermal power plants in various commercial grid environments with a view to assessing the viability of ‘on-demand’ plant performance monitoring for heat rate declaration. The plants of various types are limited to coal- and oil-fired units in the capacity range of 305–690 MW generated output. The paper illustrates the influence of control system configuration on effective and flexible power plant management. The analysis of variability indicates that there is a reasonable probability of achieving adequately stable operating periods within the normal operating envelope of grid dispatch instructions when thermal performance monitoring and display can be undertaken with a high confidence level. The levels of variability in fuel quality, which were measured during nominally constant levels of fuel input and generated output, range from about +1 per cent for oil-fired plants to about ±5 per cent for coal-fired power plants. The implications of adopting on-line monitoring of unit heat rate as an input to the generation ordering and unit commitment process are potentially significant cost and energy conservation benefits for utilities having a high proportion of coal- and oil-fired generation.

A New Calculation Approach to the Energy Balance of a Gas Turbine Including a Study of the Impact of the Uncertainty of Measured Parameters

2005 ◽  
Author(s):  
Helmer G. Andersen ◽  
Pen-Chung Chen
Keyword(s):  
Energy Balance ◽  
Gas Turbine ◽  
Control Volume ◽  
Ambient Air ◽  
Energy Balance Equation ◽  
Inlet Temperature ◽  
Exhaust Gas ◽  
Gas Composition ◽  
Intake Flow ◽  
The Impact

Computing the solution to the energy balance around a gas turbine in order to calculate the intake mass flow and the turbine inlet temperature requires several iterations. This makes hand calculations very difficult and, depending on the software used, even causes significant calculation times on PCs. While this may not seem all that important considering the power of today’s personal computers, the approach described in this paper presents a new way of looking at the gas turbine process and the resulting simplifications in the calculations. This paper offers a new approach to compute the energy balance around a gas turbine. The energy balance requires that all energy flows going into and out of the control volume be accounted for. The difficulty of the energy balance equation around a gas turbine lies in the fact that the exhaust gas composition is unknown as long as the intake flow is unknown. Thus, a composition needs to be assumed when computing the exhaust gas enthalpy. This allows the calculation of the intake flow, which in turn provides a new exhaust gas composition, and so forth. By viewing the exhaust gas as a flow consisting of ambient air and combusted fuel, the described iteration can be avoided. The study presents the formulation of the energy balance applying this approach and looks at the accuracy of the result as a function of the inaccuracy of the input parameters. Furthermore, solutions of the energy balance are presented for various process scenarios, and the impact of the uncertainty of key process parameter is analyzed.

scholarly journals ON THE SOLUTION OF ENERGY BALANCE EQUATION SYSTEM TO PREDICT TEMPERATURE DISTRIBUTION IN THE BUILDING ELEMENTS WITH VENTILATED AIR GAP

2014 ◽  
Vol 21 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Edmundas Monstvilas ◽  
Karolis Banionis ◽  
Jurga Poderytė ◽  
Raimondas Bliūdžius ◽  
Arūnas Burlingis
Keyword(s):  
Heat Exchange ◽  
Balance Equation ◽  
Heat Balance ◽  
Internal Surface ◽  
Equation System ◽  
Energy Balance Equation ◽  
Air Gap ◽  
Exchange Processes ◽  
Calculation Results ◽  
Thermal Indicators

The article presents the solution of heat balance equation system, describing heat exchange processes in ventilated envelopes, which was applied to derive formulas for the calculation of temperatures in the ventilated layers of the envelopes. The accurateness of the formulas was assessed by experimental research and analysis of the calculation results. During the process of heat exchange balance equation solution, the equations were simplified by introducing the following restriction into the derived formulas: they may only be applied for the ventilated envelopes with steel or similar coatings as their external layers, i.e. coatings having small heat capacity and minor difference between the external and internal surface temperatures. The derived formulas enable the calculation of the temperatures of the ventilated envelopes in the distance which does not exceed a half of the ventilated air gap length measuring from the air entrance into the gap. However, this restriction does not impede the estimation of the average thermal indicators of the ventilated envelopes.

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