Thermodynamic Analysis of a Jet Engine Using a Liquid Propellant

Combustion-chamber is a critical component of the propulsion engine, which is widelyused in the space industry and aeronautics. The goal of this article is to perform a numericalanalysis on the combustion process using a liquid-type propellant. The steps that must be followeduntil total combustion is achieved are emphasized. It concerns the fuel feeding phase, its injectionand the combustion operation. The amount of combustion products and the energy generated areevaluated. It has been shown that the liquid propellant may present an efficient alternative fuelthan the kerosene. In addition, the temperature of combustion does not exceed a certain limit toavoid structural problems in the chamber. The parametric survey allowed determining the range ofthe most influence factors, including the pressure, mixture richness, velocity and flow rates ofinjection for the fuel and oxidizer. The number and type of injectors revealed a considerableinfluence on the velocity and flow rates of injection. To maximize thrust force and systempropulsion, a careful selection of chamber material and ignition methods is required. A thorough inspection on the issues of walls cooling showed the necessary survey of maximum temperaturesthat may be reached during the combustion. Finally, an investigation of the thermal exchangethrough the walls will be very interesting.

Applications of the continuously rotating detonation to combustion engines at the Łukasiewicz - Institute of Aviation

In the paper short information about advantages of introduction of detonation combustion to propulsion systems is briefly discussed and then research conducted at the Łukasiewicz-Institute of Aviation on development of the rotating detonation engines (RDE) is presented. Special attention is focused on continuously rotating detonation (CRD), since it offers significant advantages over pulsed detonation (PD). Basic aspects of initiation and stability of the CRD are discussed. Examples of applications of the CRD to gas turbine and rocket engines are presented and a combine cycle engine utilizing CRD are also evaluated. The world's first rocket flight powered by liquid propellant detonation engine is also described.

DIFFUSION-VACUUM TECHNOLOGY OF MANUFACTURING LARGE AXISYMMETRIC ASSEMBLIES OF METAL MESH MATERIALS FOR HEAT EXCHANGE PATHS

Requirements for improving the reliability, service life, and increasing a specific pulse of liquid-propellant rocket engines justify a need for transfer to new designs and manufacturing technologies of regenerative engine cooling system. The paper describes a advanced diffusion-vacuum technology of manufacturing a regenerative cooling circuit for liquid-propellant rocket engine based on the concept of inter-channel coolant transpiration through a porous metal mesh material. The method of diffusion welding of metal wire mesh in vacuum makes it possible to obtain large axisymmetric blanks of metal mesh materials necessary to manufacture the regenerative cooling path of the liquid-propellant rocket engine and recuperative heat exchanger (RHE). The possibility of developing a high-efficient low-gradient porous heat exchange path obtained using a metal mesh material (MMM) has been experimentally confirmed. It is recommended to use metal woven cloth and twill filter screens of standard size П24–П60, С120 as a basic material for manufacturing MMM. Key words: diffusion-vacuum technology, porous mesh material, regenerative cooling system, inter-channel coolant transpiration.

MATH MODEL OF A DIRECT CURRENT MOTOR FOR STEERING ACTUATOR OF A LIQUID-PROPELLANT ENGINE

The paper presents the results of development of a math model for a direct current motor of a liquid-propellant engine steering actuator In accordance with the electrical machine theory, the math model of the motor uses a single electromagnetic coefficient. It is shown that the motor math model accuracy can be improved through the use, instead of a single electromagnetic coefficient, of two different coefficients of the math model: Electromechanical velocity coupling coefficient and torque curve coefficient. Elaborated and proposed are methods for identifying parameters of a math model of a dc motor that has natural and artificial static characteristics, which include determining its experimental static characteristics, calculating the values of static characteristics parameters using the linear regression method and calculating the values of the electric motor math model parameters using the proposed formulas. Key words: direct current electric motor, math model, parameter identification method.

Thrust characteristics of compact high-voltage pulsed plasma thruster utilizing liquid propellant

In this work, we present the results on thrust performance of 0.5 kg sub-joule pulsed plasma thruster prototype based on a high-voltage transformer with magnetic storage capable of work at frequency of 400 Hz. The discharge unit is made of ferroelectric ceramics with an option for utilizing liquid propellant. In case of vacuum oil as a propellant, we obtained values of thrust of ~ 80 nN·s per discharge and 33 μN·s for 400 pulses in 1 second.

Current problems in the low-frequency dynamics of liquid-propellant rocket propulsion systems

One of the key problems in liquid-propellant rocket engine (LPRE) design is to provide the stability of LPRE working processes, in particular low-frequency stability. In LPRE experimental tryout, every so often there occur situations where the development of divergent oscillations set up in some of the LPRE loops or units results in contingencies: exceeding the engine ultimate strength, pump stall, chamber ignition, etc. Such contingencies may lead to grave consequences, including engine and bench equipment failure. Because of this, mathematical simulation is one of the main tools that allow one to predict he dynamic performance of an LPRE both in its steady operation and in transients and its startup operation features at the design and tryout stage. This paper overviews and analyzes scientific publications for the past 15 years concerned with the study of the dynamics and low-frequency stability of advanced LPREs and units thereof along different lines. This analysis made it possible to identify problems in low-frequency stability prediction and assurance for liquid-propellant rocket propulsion systems (LPRPSs) under design, to cover new research results (experimental and theoretical) on the origination and development of all-engine low-frequency oscillations and low-frequency oscillations in LPRPS systems and units and to identify new approaches to the mathematical simulation and study of low-frequency processes in LPRPSs and promising lines of investigation. The man lineы of the analysis are as follows: the low-frequency dynamics of cavitating inducer-equipped centrifugal pumps and LPRE gas paths, LPRE thrust control problems, the interaction of launch vehicle airframe longitudinal oscillations with low-frequency processes in the sustainer LPRPS, dynamic processes during an LPRE startup/shutdown, and low-frequency in-chamber oscillations.