A High Precision Direct Integration Scheme Based on Variational Principle and Its Applications

Dynamics response of systems to impact or loading may be effectively treated by direct integration. However, it is often difficult to select the time-step of integration properly, especially in the case which the system is badly stiff. High Precision Direct integration based on variational principle is given (HPD-VP) for homogeneous systems and HHPD-VP method for the nonhomogeneous systems are given. This method not only takes the advantage of variational principle formula, which is much precise and is stiff A-stable, but also can avoid the truncation error of the computer. For the large systems, especially, the systems with different frequency or the stiff systems, our methods are stable, accurate and efficient. Numerical experiments show the convergence order of the scheme derived from the variational principle, and is much precise and is effective in engineering

Modeling and Simulation of IGCC Considering Pressure and Flow Distribution of Gasifier

The integrated gasification combined cycle (IGCC) is a power generation technology which combines clean coal technology with a combined cycle. The system modeling is significant for design, operation and maintenance of the IGCC power plant. However, the previous IGCC modeling methods only contained a simplified compartment gasifier model, which is useful to consider the heat transfer and chemical reaction inside the gasifier, but cannot analyze the pressure and flow distribution. In order to obtain a more accurate model of IGCC system, the volume-resistance technique and modular modeling method are utilized in this paper. The new model can depict the dynamic response and distribution characteristics of the gasifier, as well as their influence on the IGCC system. The simulation result of the gasifier and IGCC system shows an obvious delay after considering pressure and flow distribution. Therefore, the proposed IGCC system model can obtain a more reliable result when considering the distribution characteristics of the gasifier

IMECE2002-33189 THE HARDWARE-IN-THE-LOOP SIMULATION STUDY ON THE CONTROL STRATEGY OF GAS TURBINE of power machinery and engineering of education ministry

ABSTRACT A 3-shaft gas turbine engine for ship propulsion was taken as an object to establish the hardware-in-the-loop simulation system, which is composed of computers, real physical parts, measuring instruments, interfaces between physical parts and computers, and the network for communication, as well as the relevant software including mathematical models of the gas turbine engine. "Hardware-in-the-loop" and "volume inertia effects" are the two major features of this simulation system. In comparison with traditional methods for gas turbine simulation, the new simulation platform can implement simulation in real time and also can test the real physical parts performance through integration of the real physical parts and the mathematical model in a computer. INTRODUCTION "Hardware-in-the-loop simulation" is a strong tool to study the dynamic process in a gas turbine engine. However, many difficulties exist to establish the simulation system. Firstly, the effective communication between the real physical parts and the mathematical model should be resolved. Secondly, the mathematical model calculation in the computer must occur in real time. In order to overcome these difficulties, we not only need to construct hardware in the loop simulation platform to effectively and quickly transfer data; but we also need to develop the mathematical model and corresponding algorithm of the simulation object-the gas turbine engine, and then to synchronize the calculation process with the real processes of the physical parts. A 3-shaft gas turbine engine for ship propulsion is taken as an object to establish the hardware-inthe-loop simulation platform, with which the control strategy is investigated

A High Precision Direct Integration Scheme Based on Variational Principle and Its Applications

Dynamics response of systems to impact or loading may be effectively treated by direct integration. However, it is often difficult to select the time-step of integration properly, especially in the case which the system is badly stiff. High Precision Direct integration based on variational principle is given (HPD-VP) for homogeneous systems and HHPD-VP method for the nonhomogeneous systems are given. This method not only takes the advantage of variational principle formula, which is much precise and is stiff A-stable, but also can avoid the truncation error of the computer. For the large systems, especially, the systems with different frequency or the stiff systems, our methods are stable, accurate and efficient. Numerical experiments show the convergence order of the scheme derived from the variational principle, and is much precise and is effective in engineering

PERFORMANCE RESEARCH OF HIGH TEMPERATURE COMPACT OFFSET STRIP FIN HEAT EXCHANGER The key Lab. of power machinery and engineering of education ministry

ABSTRACT NOMENCLATUR