PC GRAD

The program complex 'Gas dynamic analysis of aviation engines and power plants ' (PC GRAD PP) is one of gas turbine engines (GTE) CAD subsystems (system of the automated design).

The program complex GRAD is the open system supposing connection of modules of any necessary units and modules realizing new tasks. It provides modelling of engines in which is available up to 5 shafts and up to 5 contours with an opportunity of its increasing if necessary. The total number of units in the scheme is no more than 50. PC has the input language for the description practically any programs of the engine control that are realized during performance of calculations automatically. The connection of available mathematical models of GTE automatic control systems to the PC GRAD is provided. The GRAD allows to analyze various kinds of characteristics: (throttle, altitude-speed , climatic, rolling and so on) on the stationary modes; various characteristics on transitive operating modes, including jet thrust response, reciprocal acceleration, ejection of the fairing and opposing љejection of the fairing, and also start of the engine (starter characteristics either are determined, or can be calculated). The characteristics presentation is set through input data and the structure of the output information is defined by it also.

The PC GRAD allows calculating tables of influence factors, each of them shows, how the response will change after change of the factor for one percent. Any parameters from the input data can use as a factors, and responses could be any parameters from a file of results. There is an opportunity to change their places. Tables are calculated on any modes.

The PC GRAD allows making scanning of results, i.e. to survey the set area in the found decision neighborhood, and the area is set by any factor.

The PC GRAD allows counting any of mentioned above characteristics in a fuzzy numbers, i.e. with set possible change limits on some input parameters. In this case the automatic choice of critical combinations of the parameters corresponding extreme values of results, received in fuzzy numbers, is provided.

The PC GRAD allows counting stochastic characteristics where the spread simulated is imposed on a part of input data by the random-number generator. Three types of sensors with uniform, normal and normal truncated distribution laws are applied. The opportunity of connection of other sensors is stipulated. The spread is imposed for imitation of measurement errors, of mode installation errors and manufacturing errors. Results turn out in the form of distribution law parameters.

The PC GRAD provides graphic processing the received results, i.e. their representation in the graphic form which kind is preset for each task for reduction of input information amount. The opportunity of reception of an any kind of graphs is stipulated.

The PC GRAD allows choosing the engine features, i.e. to choose parameters and the basic dimensions of a setting providing creation of the engine with the set specifications.

The PC GRAD allows making of the engine parameters optimization that provides a maximum or a minimum of the defined scalar or vector target function. Thus any parameters of input data can vary, and any restrictions can be imposed on the output data. Various algorithms of optimization with their automatic choice during search are used.

The PC GRAD provides identification of the engine mathematical model by results of its tests in the test bed or in flight, during such identification the refinement of the improbable information in the input data set by the user is made. This module provides identification on the stationary modes by the measured parameters and on transitive modes by the parameters, got from oscillograms.

The PC GRAD allows making technical diagnostics of the engine by measured thermo gas dynamic parameters with detection one, two or three defects in the setting.

The PC GRAD provides an opportunity of transfer models reception which are used for information compression, i.e. approximation of parameters, calculated on MM, dependence working area from any set factors is spent. Transfer models are usually used in contiguous MM, for example, for analysis of the plane or GTE or GTP units or power plant as a whole.

The PC GRAD provides calculation of the linear dynamic models factors used at calculation of the engine control systems.

The PC GRAD provides estimated calculations of GTE weight (aviation engines only), its dimensions and also the moments of inertia of rotors under the statistical information.

The PC GRAD in last versions works on personal computers only.

The PC GRAD is provided with author's support which can be prolonged for any desirable term under the contract.

The PC GRAD is provided by the documentation for the user on an electronic medium in Russian and in English.