Determination of characteristic frequencies of elastic oscillations of the <Emphasis Type="Italic">International Space Station</Emphasis> construction

The results of investigating free oscillations of the International Space Station construction appearing during spacecraft docking and undocking are described. The study is carried out using the measurement data of the low-frequency MAMS accelerometer. Several intervals of measurements performed in 2005 and 2006 were chosen to be studied. For chosen intervals, only the data intervals corresponding to the process of free attenuation of the oscillations construction elements were analyzed. Characteristic frequencies of elastic oscillations of the station construction and attenuation coefficients corresponding to them are found. The comparative analysis of the results obtained for various docking ports (nodes) is carried out. The described study is performed as a part of the technical experiment “The ISS Environment” carried out onboard the station in accordance with the Russian program of scientific and engineering experiments.     

Algebraic operations on graphs with using numeric coding for simulating the systems of rocket and space technology

The paper adduces the relators for algebraic operations on graphs using the numeric codes of the graphs. The special algebra of codes has been devised with consideration of the principles of graph transformation. This paper demonstrates the relevance of numeric coding of graphs for solving the problems of enumeration, systematization, and compact representation of the information about the structural and functional characteristics of the systems of flow distribution and conversion of rocket and space technology and for conducting the modeling transformations of given systems in the course of the structural and functional studies as well.     

Concept of monitoring for thermostressed state and service life of aircraft gas turbine engine blades

A concept of monitoring for material properties with residual life estimation of rotor blades for gas turbine engines is proposed. The structure of on-board control and conditionmonitoring system based on the intelligent pyrometer module with the algorithm for calculating the residual life of turbine rotor blades is described.     

Analysis of a beam with a crack under irregular cyclic load

This paper considers a beam with a technological longitudinal section on the level of the gravity center of the cross section that is loaded by a vertical concentrated force. We study the structure durability depending on the load amplitude and the initial crack length.     

Improvement of gas-dynamic efficiency of GTE gas turbine stages at the design stage

Methods to control flow have been considered in order to reduce end losses in blade rows of GTE gas turbines by means of measures taken at the design stage.     

低排放燃烧室NO_x排放试验及预测方法研究

为了研究中心分级贫油低排放燃烧室的排放特性和排放预测方法,针对一个低排放头部方案,在单头部燃烧室试验件上,在不同的温度、压力、油气比、供油模式和分级比条件下,测量其排放性能。以Lefebvre排放经验预测公式为基础,采用经验分析方法拟合排放试验数据,归纳出适用于本头部方案的排放预测公式。表征预测好坏的判定系数R2在小工况下和大工况下分别为0.95和0.93,表明预测结果与试验结果符合度较好。小工况和大工况排放特性不同,对仅预燃级喷油的小工况工作模式,NO_x排放主要受化学恰当燃烧温度和预燃级局部当量比的影响;对预燃级和主燃级同时喷油的大工况工作模式,NO_x排放主要受燃烧区温度和主燃级燃油比例的影响。     

The Electric Antennas for the STEREO/WAVES Experiment

The STEREO/WAVES experiment is designed to measure the electric component of radio emission from interplanetary radio bursts and in situ plasma waves and fluctuations in the solar wind. Interplanetary radio bursts are generated from electron beams at interplanetary shocks and solar flares and are observed from near the Sun to 1 AU, corresponding to frequencies of approximately 16 MHz to 10 kHz. In situ plasma waves occur in a range of wavelengths larger than the Debye length in the solar wind plasma λ _D ≈10 m and appear Doppler-shifted into the frequency regime down to a fraction of a Hertz. These phenomena are measured by STEREO/WAVES with a set of three orthogonal electric monopole antennas. This paper describes the electrical and mechanical design of the antenna system and discusses efforts to model the antenna pattern and response and methods for in-flight calibration.