The method of advanced bypass turbojet engine core research tests with simulation of target inlet thermogasdynamic parameters at the engine OEM site is considered. It is stated that research testing is traditionally associated with the use of multifunctional test facilities capable of simulat-ing operating conditions as close as possible to operational ones for a wide range of test objects of different thrust (power) and application. Such test facilities require significant investment and operating costs, which in general determines their limited number in the world. It is shown that the steady growth of the share of research tests at the initial design stages requires organization of tests with minimal financial and material costs directly at the engine OEM site, where testing the advanced bypass turbojet engine core plays a special part. Determination of the method for simulating thermogasdynamic parameters is associated with solution of rather contradictory problems, where, on the one hand, it is required to ensure reliable reproduction of the actual operating conditions of the core for all configurations of the bypass turbojet engine under development, and on the other hand, to ensure lower manpower and cost of testing. One of the effective solutions is the use of specialized test facilities, a distinctive feature of which is determination of the simplest and most economical means of obtaining the working fluid with the required thermogasdynamic parameters for a pre-determined range of test objects of different thrust (power) and application. The technical implementation of the dedicated test facility for testing the advanced bypass turbojet engine core at UEC-Aviadvigatel JSC (Perm) is considered.
Continuous improvement in the operational characteristics of gas turbine equipment and a significant reduction in the time of its creation have led to the development and application of new technologies for conducting research tests of a gas generator—the basic section of a bypass turbojet engine. Carrying out such tests requires the reproduction of the thermo gas dynamic parameters of the working fluid at the gas generator inlet to ensure maximum similarity to the processes occurring in the engine being designed. Obtaining a working fluid with the required thermo gas dynamic parameters such as temperature, pressure, and air flow rate is carried out on the basis of a test complex. The test complex, as a control object, is a non-linear, non-stationary, multi-variable system, where each controlled variable substantially depends on other control actions. The article presents the main aspects of the behavior of the object under consideration, which are the basis for the development of an automated test system and, in particular, the principles of forming control algorithms based on the theory of fuzzy logic. The graphs of the state and control of the main elements of the test complex are presented. Special attention is given to the analysis of the proposed control algorithms.
При создании современных авиационных газотурбинных двигателей отмечается значительное усложнение систем автоматического управления и контроля, а их задачи управления являются нетривиальными по множеству причин. Для решения этих задач необходима адекватная математическая модель системы автоматического управления в реальном масштабе времени. Наличие такой модели создает предпосылки для решения задач управления, а также дает возможность обеспечения информационной избыточности, которая позволяет повысить отказоустойчивость системы автоматического управления, т.е. ее способность выполнять свои функции после появления неисправностей. В статье представлены результаты анализа математической модели современной системы автоматического управления газотурбинного двигателя на одном из стационарных и одном из переходных режимов функционирования. Анализ включает рекуррентную идентификацию коэффициентов математической модели, оценивание точности идентификации и определение статистических характеристик измерительных и системных шумов. Идентификация проводилась на основе измерительной информации, полученной в результате летных испытаний авиационного газотурбинного двигателя. Применялись методы регрессионного и дисперсионного анализа. Для определения оптимальных оценок коэффициентов математической модели использовался метод наименьших квадратов в движущемся окне. Этот метод позволяет получить несмещенные оценки коэффициентов с минимальной дисперсией. Проводилась оптимизация ширины движущегося окна с целью обеспечения минимума времени запаздывания оценок сигнала выхода модели и требуемой точности идентификации на всех режимах функционирования двигателя. Точность идентификации оценивалась по коэффициенту детерминации. Результаты анализа математической модели системы автоматического управления для одного из стационарных из переходных режимов представлены в виде таблиц и графиков. Показано, что предложенный алгоритм идентификации обеспечивает выполнение требований по точности определения оценок сигналов выхода системы автоматического управления газотурбинного двигателя и времени их запаздывания. Ключевые слова: математическая модель, идентификация, метод наименьших квадратов, оценивание, дисперсионный анализ, рекуррентная идентификация.
The possibility of obtaining measuring in-formation about the parameters of the automatic control and monitoring system of a turbofan engine during its operation in flight conditions and almost no restrictions on computational costs enable using algo-rithmic methods to improve the engine fault tolerance. In the previous article, the optimal observer, the Kalman filter, was used as a reserve meter. Its functioning essentially depends on the probabilistic characteristics of the system noise, which is known approximately and changes in a complex man-ner over time. Inaccuracies in these characteristics can lead to filter divergence and loss of its stability. To solve this problem, it is proposed to use the Yazvinsky adaptive filter, which allows calculating the covariance matrix of the disturbance noise after the arrival of new measurements from the values of the updated process of the Kaman filter. In this case computational costs increase insignificantly. The use of the Yazvsky adaptive filter eliminates the need for preliminary correlation analysis of system noise and pro-tects the Kalman filter from loss of stability. The results of modeling the Yazvinsky filter, consistent with the mathematical model of the turbofan engine, based on the flight test data of the PS-90A type engine as part of the TU-214 aircraft, both in steady-state and transient modes of engine operation, are presented. The parameters are indicated as percentage of the maximum values. A comparative analysis of the actual errors in the estimation of the output vector of the turbofan engine ACS when Kal-man and Yazvinsky filters are operating is carried out. The results of the comparative analysis are presented in the form of tables and graphs. It is shown that the proposed algorithm ensures fulfillment of the requirements for the accuracy of estimating the output vector of the automatic control and monitoring system of a gas turbine engine and can be recommended for use in the ACS of the turbofan engine.
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