A technique for presentation and application of the propeller fan multidimensional characteristics in semi-full-scale simulation of a gas turbine engine and its automatic control system

A technique for linear interpolation of the multidimensional characteristics of a coaxial propeller fan with opposite rotation propellers is proposed; the technique makes it possible to simulate the turbofan engine operation in the entire range of flight conditions and reduce expenses for fullscale tests. The mathematical models obtained meet the requirements imposed in the semi-full-scale simulation.     

Pareto-optimal solution of a two-objective problem in choosing conditions of monoimpeller milling

A problem of optimization of cutting parameters with respect to the criteria of maximum efficiency and maximum tool resistance is formulated. To solve the problem, a method is developed and applied for determining the Pareto-optimal values of machining conditions in milling the present-day GTE monoimpeller blade passages with a circular milling cutter.     

Gasodynamic characteristics of a combustion chamber in the integrated power plant with an asymmetric air intake

The results of experimental investigations of gasodynamic characteristics of a combustion chamber model in the integrated power plant (IPP) with an asymmetric air intake are presented. The influence of an angle of air supply into the chamber model on hydraulic losses and the flow structure is shown at different air flowrates, relative values of the minimal flow section area of the feeding air intake pipes, under changes of the flowrate of gas simulating gas generation products and geometric model parameters. A technique for measuring the concentration of carbon dioxide simulating IPP gas generation products in the combustion chamber air flow and the results of experimental investigations of a mixture formation process in the combustion chamber model are described.     

Analysis of structural elements made of composite materials with defects

The paper presents an improved technique and the results of strength analysis for the aircraft structural elements with a structural defect like an arbitrary shape delamination.     

Difference schemes in computations for chemically non-equilibrium processes in the rocket engine nozzles

The problem of determining the “potential” number of integration steps by explicit difference schemes is solved within the framework of the prediction model for chemically non-equilibrium processes.     

Calculation of low cycle fatigue life for gas-turbine engine critical parts

The paper presents a technique of calculating the life for gas turbine engine parts in a low cycle area based on the influence coefficients taking into account analytical and operational factors. A statistical method is used to determine the influence coefficients.     

Multi-criteria analysis of aircraft structures fracture

A novel modular multistep algorithm is proposed for multi-criteria analysis of fracture of aircraft structures with complex geometries. In order to evaluate the algorithm, the crack growth analysis is realized by the following three criteria, namely, the stress intensity factor, the strain energy release rate, and the J-integral. The algorithm implementation by the finite element method is considered and prospects of alternative implementation based on the meshfree methods are assigned.     

Development of the Technique for Calculating the Ejectors with Low Entrainment Ratios

This paper presents the results of an investigation of ejectors with the low entrainment ratio. A technique for calculating the ejectors with a curvilinear axis has been developed. Comparative studies of the performance characteristics of ejectors with the rectilinear axis of the mixing chamber and the curvilinear initial section of the mixing chamber are carried out.     

Periodicities of the LDE-type flare occurrence (1969 - 1992).

The power spectrum was calculated for the time series of the LDE-type flare occurrence during the last three solar cycles (the 20-th, the 21-st and the first part of the 22-nd cycle). LDE-type flares (Long Duration Events in SXR) are associated with the interplanetary protons (SEP and STIP as well), energized coronal arches and radio type IV emission. Generally, in all the cycles considered, LDE-type flares mainly originated during a 6-year interval of the respective cycle (2 years before and 4 years after the sunspot cycle maximum). The following significant periodicities were found: in the 20-th cycle: 1.4, 2.1, 2.9, 4.0, 10.7 and 54.2 of month; in the 21-st cycle: 1.2, 1.6, 2.8, 4.9, 7.8 and 44.5 of month; in the 22-nd cycle, till March 1992: 1.4, 1.8, 2.4, 7.2, 8.7, 11.8 and 29.1 of month; in all interval (1969-1992): 1. the longer periodicities: 232.1, 121.1 (the dominant at 10.1 of year), 80.7, 61.9 and 25.6 of month, 2. the shorter periodicities: 4.7, 5.0, 6.8, 7.9, 9.1, 15.8 and 20.4 of month. Solar variability has an extremely complex time dependence. The Sun is a multiperiodic system. The strong periodicities "near 155 and 270 days" were found also in the LDE-type flare occurrence.     

A high-performance ground-based prototype of horn-type sequential vegetable production facility for life support system in space

Vegetable cultivation plays a crucial role in dietary supplements and psychosocial benefits of the crew during manned space flight. Here we developed a ground-based prototype of horn-type sequential vegetable production facility, named Horn-type Producer (HTP), which was capable of simulating the microgravity effect and the continuous cultivation of leaf–vegetables on root modules. The growth chamber of the facility had a volume of 0.12 m³, characterized by a three-stage space expansion with plant growth. The planting surface of 0.154 m² was comprised of six ring-shaped root modules with a fibrous ion-exchange resin substrate. Root modules were fastened to a central porous tube supplying water, and moved forward with plant growth. The total illuminated crop area of 0.567 m² was provided by a combination of red and white light emitting diodes on the internal surfaces. In tests with a 24-h photoperiod, the productivity of the HTP at 0.3 kW for lettuce achieved 254.3 g eatable biomass per week. Long-term operation of the HTP did not alter vegetable nutrition composition to any great extent. Furthermore, the efficiency of the HTP, based on the Q-criterion, was 7 × 10⁻⁴ g² m⁻³ J⁻¹. These results show that the HTP exhibited high productivity, stable quality, and good efficiency in the process of planting lettuce, indicative of an interesting design for space vegetable production.