Improved Transient Control of a Two-Stroke Marine Diesel Engine With Variable Geometry Turbine

2011 ◽  
Author(s):  
Nikolaos I. Xiros ◽  
Gerasimos Theotokatos
Keyword(s):  
Power Plant ◽  
Process Model ◽  
Mass Conservation ◽  
Momentum Conservation ◽  
Mean Value ◽  
Neural Nets ◽  
Algebraic Equations ◽  
Real Time Control ◽  
Basic Principles ◽  
Functional Relationships

In this work, the cycle-mean-value approach to marine engine process simulation is considered. At first, a basic principles model is employed where the engine crankshaft and turbocharger shaft speeds are obtained by integration of the angular momentum conservation differential equations. Any other engine variable can then be obtained by solving a set of nonlinearly-coupled, algebraic equations, corresponding to energy and mass conservation through the engine. Nonlinear data analysis is then performed on this process model. By approximating the torque maps, generated by the thermodynamic basic principles model, with neural nets, explicit functional relationships are obtained. Identification of the power-plant operating regimes through linearization and decomposition is finally performed. In effect, a supervisory power-plant controller structure, applicable to real-time control and diagnostics, is proposed, incorporating the nonlinear state-space description of the plant.

Investigation of a Nonlinear Control Model for Marine Propulsion Power-Plants

2011 ◽  
Author(s):  
Nikolaos I. Xiros
Keyword(s):  
Power Plant ◽  
State Space ◽  
Thermodynamic Model ◽  
Power Plants ◽  
Mean Value ◽  
Neural Nets ◽  
Real Time Control ◽  
Functional Relationships ◽  
Time Control ◽  
Space Description

A cycle-mean-value, quasi-steady, thermodynamic model of slow-speed, two-stroke marine Diesel engines, used for performance prediction and engine-propeller/turbocharger matching, is converted into a power-plant analytic model. The dynamic part of the cycle-mean model consists of the two first-order differential equations for the cycle-mean crankshaft and turbocharger shaft rotational accelerations. This form implies a state-space formulation of the power-plant modeling approach. However, engine, turbine and compressor torques have to be calculated through the solution of the algebraic part of the model, which consists of a nonlinear, perplexed algebraic system of equations not analytically solvable. This inhibits the formulation of the power-plant state-space description. By approximating the torque maps, generated by the thermodynamic model, with neural nets, explicit functional relationships are obtained. Identification of the power-plant operating regimes through linearization and decomposition is performed. In effect, a supervisory power-plant controller structure, applicable to real-time control and diagnostics, is proposed, incorporating the nonlinear state-space description of the plant.

scholarly journals Detailed description of the evolution mechanism for singularities in the system of pressureless gas dynamics

2019 ◽  
Vol 484 (6) ◽  
pp. 655-658 ◽  
Author(s):  
A. I. Aptekarev ◽  
Yu. G. Rykov
Keyword(s):  
Gas Dynamics ◽  
Variational Approach ◽  
Large Scale ◽  
Burgers Equation ◽  
Mass Conservation ◽  
Momentum Conservation ◽  
Material Objects ◽  
Vector Equation ◽  
Basic Principles ◽  
The Universe

The system of pressureless gas dynamics is a hydrodynamically justified generalization of the system consisting of the Burgers vector equation in the limit of vanishing viscosity and the mass conservation law. The latter system of equations was intensively used, in particular, in astrophysics to describe the large scale structure of the Universe. The solutions of the vector Burgers equation involve interesting dynamics of singularities, which can describe concentration processes. However, this dynamics does not satisfy the law of momentum conservation, which prevents us from treating it as dynamics of material objects. In this paper, momentum-conserving dynamics of singularities is investigated on the basis of the pressureless gas dynamics system. Such dynamics turns out to be more diverse and complex, but it is also possible to formulate a variational approach, for which the basic principles and relations are obtained in the work.

Dynamic Optimization of Startup and Load-Increasing Processes in Power Plants—Part II: Application

1999 ◽  
Vol 123 (1) ◽  
pp. 251-254 ◽  
Author(s):  
J. Bausa ◽  
G. Tsatsaronis
Keyword(s):  
Power Plant ◽  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Dynamic Optimization ◽  
Process Model ◽  
Optimal Operation ◽  
Combined Cycle ◽  
Algebraic Equations ◽  
First Order ◽  
Load Increase

In the first part of this study, a general method for solving dynamic optimization problems has been presented: the dynamic process model, consisting of first-order ordinary differential equations (ODEs) and algebraic equations, is discretized over the time horizon using well established methods for the solution of ODEs. The discretized system is then treated as large-scale non-linear parameter optimization problem. This transformation is implemented in a user-friendly software package. An application of this software is demonstrated in the present paper by optimizing the process of rapid load-increase in a single-pressure combined-cycle power plant. The power plant is described with a simplified model that consists of 18 first order ordinary differential equations and 67 algebraic equations. For this model a time-optimal operation associated with a load increase from 50 percent to 75 percent of base load is calculated by considering given restrictions on some temperature gradients.

Influence of new surface micro-structures on the performance behaviours of fluid film tilting pad thrust bearings

2021 ◽  
pp. 095440622110309
Author(s):  
JC Atwal ◽  
RK Pandey
Keyword(s):  
Mass Conservation ◽  
Performance Parameters ◽  
Algebraic Equations ◽  
The Finite Element Method ◽  
Thrust Bearings ◽  
Lubrication Equation ◽  
Tilting Pad ◽  
Minimum Film Thickness ◽  
Newton Raphson ◽  
Micro Structures

Performance parameters such as power loss, minimum film thickness, and maximum oil temperature of the sector-shaped tilting pad thrust bearings employing the new micro-structural geometries on pad surfaces have been investigated. The lubrication equation incorporating the mass-conservation issue is discretized using the finite element method and the solution of resulting algebraic equations is obtained employing a Newton-Schur method. The pad equilibrium in the analysis is established using the Newton-Raphson and Braydon methods. The influence of attributes of micro-structures such as depth, circumferential and radial positioning extents have been explored on the performance behaviours. It is found that with the new micro-structured pad surfaces, the performance parameters significantly improved in comparison to conventional plain and conventional rectangular pocketed pads.

scholarly journals 14C Release in Various Chemical Forms With Gaseous Effluents From the Paks Nuclear Power Plant

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 754-761 ◽  
Author(s):  
Ede Hertelendi ◽  
György Uchrin ◽  
Peter Ormai
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Liquid Scintillation ◽  
Mean Value ◽  
Scintillation Counting ◽  
Pressurized Water ◽  
The Mean ◽  
Water Reactors

We present results of airborne 14C emission measurements from the Paks PWR nuclear power plant. Long-term release of 14C in the form of carbon dioxide or carbon monoxide and hydrocarbons were simultaneously measured. The results of internal gas-proportional and liquid scintillation counting agree well with theoretical assessments of 14C releases from pressurized water reactors. The mean value of the 14C concentration in discharged air is 130Bqm-3 and the normalized release is equal to 740GBq/GWe · yr. > 95% of 14C released is in the form of hydrocarbons, ca 4% is apportioned to CO2, and <1% to CO. Tree-ring measurements were also made and indicated a minute increase of 14C content in the vicinity of the nuclear power plant.

Power Plant Pump Process Model Error Minimization Technique for Improving Simulator Fidelity

2021 ◽  
Author(s):  
SooYong Yun ◽  
Kwan-Woong Gwak ◽  
Seung-Hyun Byun ◽  
Deockho Kim ◽  
Jaeyong Cho ◽  
...  
Keyword(s):  
Power Plant ◽  
Process Model ◽  
Model Error ◽  
Error Minimization ◽  
Minimization Technique

Real-Time Control of Reactive Power in a Power Plant

1985 ◽  
Vol 18 (5) ◽  
pp. 951-956 ◽  
Author(s):  
I. Vajk ◽  
M. Vajta ◽  
K. Kovacs
Keyword(s):  
Power Plant ◽  
Real Time ◽  
Reactive Power ◽  
Real Time Control ◽  
Time Control

scholarly journals INDOOR AIR TEMPERATURE DISTRIBUTION – AN ALTERNATIVE APPROACH TO BUILDING SIMULATION

2003 ◽  
Vol 2 (1) ◽  
Author(s):  
A. T. Franco ◽  
C. O. R. Negrão
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Indoor Air ◽  
Linear Equations ◽  
Three Dimensional ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Algebraic Equations ◽  
Conservation Of Energy ◽  
Energy Conservation Equation

The current paper presents a model to predict indoor air temperature distribution. The approach is based on the energy conservation equation which is written for a certain number of finite volumes within the flow domain. The magnitude of the flow is estimated from a scale analysis of the momentum conservation equation. Discretized two or three-dimensional domains provide a set of algebraic equations. The resulting set of non-linear equations is iteratively solved using the line-by-line Thomas Algorithm. As long as the only equation to be solved is the conservation of energy and its coefficients are not strongly dependent on the temperature field, the solution is considerably fast. Therefore, the application of such model to a whole building system is quite reasonable. Two case studies involving buoyancy driven flows were carried out and comparisons with CFD solutions were performed. The results are quite promising for cases involving relatively strong couplings between heat and airflow.

Contribution to Computer Control and Optimization of Hydro-Abrasive Jet Machining Process

1991 ◽  
Author(s):  
Roberto Groppetti ◽  
Giuseppe Comi
Keyword(s):  
Real Time ◽  
Process Model ◽  
Wide Spectrum ◽  
Computer Control ◽  
Process Condition ◽  
Machining Process ◽  
Process Variables ◽  
Real Time Control ◽  
Machining Conditions ◽  
Abrasive Jet Machining

Abstract Hydro-Abrasive Jet Machining (HAJM) has demonstrated its suitability for several applications in the machining of a wide spectrum of materials (metals, polymers, ceramics, fibre reinforced composites, etc.). The paper is a contribution to the computer control, integration and optimization of HAJM process in order to establish a hierarchical control architecture and a platform for the implementation of a real-time Adaptive Control Optimization (ACO) module. The paper presents the approach followed and the main results obtained during the development and implementation of a HAJM cell and its computerized controller. A critical analysis of the process variables available in the literature is presented, in order to identify the process variables and to define a process model suitable for HAJM real-time control and optimization. Besides for HAJM computer control, in order to correlate process variables and parameters with machining results, a process model and an optimization procedure are necessary in order to avoid expensive and time-consuming experiments for the determination of optimal machining conditions. The paper presents the configuration of the cell and the specific components adopted in order to make possible a fully computerized control of the process, and the architecture of the controller, capable to manage the several logical and analogical signals from the different modules of the cell, for multiprogramming, process monitoring, controlling, process parameters predetermination, process condition multiobjective optimization. A prediction and an optimization model is presented allowing the identification of optimal machining conditions using multiobjective programming. This model is based on the definition of an economy function and a productivity function, with suitable constraints relevant to the required machining quality, the required kerfing depth and the available resources. A test case based on experimental results is discussed in order to validate the model.

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