scholarly journals Closure to “Discussion of ‘The Use of a Hybrid Computer in the Optimization of Gas Turbine Control Parameters’” (1974, ASME J. Eng. Power, 96, pp. 324–325)

1974 ◽  
Vol 96 (3) ◽  
pp. 325-325
Author(s):  
H. I. H. Saravanamuttoo ◽  
B. D. MacIsaac
1973 ◽  
Vol 95 (3) ◽  
pp. 257-264 ◽  
Author(s):  
H. I. H. Saravanamuttoo ◽  
B. D. MacIsaac

This paper discusses the hybrid computer simulation of a single-spool turbojet engine. The problem is approached from the viewpoint of engineering thermodynamics, using the normal compressor and turbine characteristics. This was found to yield an extremely flexible simulation capable of operation over the entire running range. The simulation was used to investigate methods of improving the thrust response and it was found that a detailed insight into the engine dynamics permitted a significant improvement in thrust response.


Author(s):  
T. Takeuchi ◽  
T. Itoh ◽  
T. Ishida

A conceptual design study of a regenerative high temperature gas turbine and the dynamic characteristics of a regenerator were discussed in Part I of this paper in 1979. (ASME Paper 79-GT-127). In order to further study the characteristics of the ceramic gas turbine, a mathematical model for a gas turbine vehicle system was constructed on a hybrid computer, and the dynamic characteristics of a two-shaft regenerative gas turbine were calculated. We also calculated the 10-mode fuel economy for various control systems.


Author(s):  
I. W. Schatborn

This paper describes the hybrid simulation of a single-shaft W 191 M gas turbine water pump drive, carried out to carefully adapt the control system to starting and stopping under load within plant operating limitations. For this simulation work, the hybrid computer favorably combines analog computer flexibility in the solving control problems with digital computer memory for storage of steady-state characteristics. The latter are generated using a new hybrid function generation technique for two independent variables.


Author(s):  
A. M. Foss

The requirement for gas turbine engines to operate over wider ranges has resulted in today’s more sophisticated engines with multiple controls. Current control philosophy for such powerplants is to adopt separate control systems for each of the major components with the minimum of communication between them. Interactions between the various control parameters can, however, seriously degrade the performance, and a design strategy aimed to take account of these interactions — the multivariable approach — may be better. Although several multivariable design methods have been proposed, most are highly theoretical and a need exists for a more practical straightforward procedure. This paper aims to demonstrate such a procedure, based on the characteristic locus technique, for the design of a gas turbine multivariable controller.


Author(s):  
R. Bettocchi ◽  
P. R. Spina

This paper presents an analysis of the influence of control logic on gas turbine operation, when machine load adjustments are carried out. An examination is made of the control logics that are possible for a two-shaft gas turbine with variable power turbine nozzle in order to reach the following objectives: - operation in maximum efficiency conditions; - operation in the conditions of maximum thermal power of exhaust gases at the turbine outlet; - operation at constant turbine outlet temperature; - operation with the maximum Surge Margin. The control logics necessary for reaching the predetermined objectives in the part-load operation are provided by the map of gas turbine’s main performance, thermodynamic and control parameters.


Author(s):  
Min Chul Lee ◽  
Kwang Ick Ahn ◽  
Youngbin Yoon

A conventional combustion tuning method for a gas turbine needs more than 24 hours with lots of human labor. In addition it is hard to certify whether the plant is optimized because the conventional tuning is based on human decisions and subjective empirical data over a long time. In this study we developed a combustion tuning technology using six sigma tools (CTSS) to effectively meet the increasingly stringent NOx regulations and to save combustion tuning time. CTSS was conducted in five steps—define-identify-design-optimize-verify (DIDOV). First, the NOx reduction target was defined (Step 1, define), the current status of the plant was diagnosed (Step 2, identify), and the vital few control parameters to achieve the defined target were determined by analyzing the correlation between the control parameters and NOx emissions (Step 3, design). For the next step, the optimum condition was derived from one of the six sigma tools (Step 4, optimize), and finally the optimum condition was verified by applying the condition to the gas turbine combustion (Step 5, verify). As a result of CTSS, averaged NOx emissions were reduced by more than 70% and the standard deviation was improved by more than 60%. These results show that CTSS is a potential tool for enhanced reliability of plant operations and scientific method for quick and exact combustion tuning.


Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.


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