Analysis of the oscillating plate heat exchanger at the ammonia environment as a new concept of heat exchanger for the electric rocket engine

Elektrotermiczny napęd rakietowy ze względu na prostotę swego działania i konstrukcji jest atrakcyjnym rozwiązaniem dla inżynierów projektujących systemy kontroli położenia satelitów. Ciagłe poszukiwanie nowych rozwiązań oraz stosowanie nowych materiałów konstrukcyjnych znacząco podniosły sprawność obecnych silników rakietowych, w tym elektryczno-termicznych typu "Resistojet" . Nowym rozwiązaniem proponowanym w tego typu napędach jest wymiennik ciepła z oscylującym elementern grzewczym. Dzięki temu termiczna warstwa przyścienna Charakteryzująca się znacznie większą temperaturą niż temperatura przepływającego ośrodka, powstająca na płytce jako elemencie grzewczym, odrywa się, a następnie miesza z pozostałą częścią płynu ogrzewając ją. Wykazano, że istnieje granica częstotliwości oscylacji, która w sposób znaczący poprawia efektywność grzania czynnika roboczego. Badania wykonano w ramach projektu ESA PECS 98104 Gas Resistojet Thruster for Medium Size Satellite Attitude Control.Electric rocket propulsion belong to the group of rocket engines which use thermal energy converted from electric. This energy conversion is crucial problem for this kind of rocket engines. The electric rocket engines are divided by methods of energy conversion and in this work is presented solution for resistance rocket engines called "resistojet". Resistojets are mostly used as a propulsion for attitude control system of satellite platforms because their simplicity, relative high specific impulse and long work-time duration ability. Recently development of new solutions and new materials have significantly increased the efficiency of energy conversion and decreased losses of thermal energy in resistojets. New solution proposed to the resistojets is heat exchanger with flat plate. The phenomena of thermal boundary layer created on surface of plate is additional intensify by high frequency oscillating. Because of dynamic move the boundary layer is broken and mixed in downstream flow. Mixed fluid increase own temperature and enthalpy that is converted to high velocity in the supersonic nozzle. In this work was shown that there is limitation of frequency oscillation of flat plate to enhance thermal process to heating fluid. This work was done as a part of project "ESA PECS 98104 Gas Resistojet Thruster for Medium Size Satellite Attitude Control"

Symulacje silnika z wirujacą detonacją (RDE) w kodzie REFloPS

The paper presents the results of three-dimensional preliminary simulations of a detonation propagating in Rotating Detonation Engine chamber. Simulations were performed using in-house code REFloPS (Reactive Euler Flow Solver for Propulsion Systems)[1]. The description of the code and presented results are also included in MSc thesis of Folusiak and Swiderski [2].W artykule przedstawiono wyniki trójwymiarowych symulacji detonacji w komorze silnika z wirującą detonacją (RDE). Symulacje przeprowadzono przy użyciu kodu REFloPS, który jest wynikiem pracy magisterskiej dwóch pracowników Instytutu Lotnictwa

Numerical tools for three dimensional simulations of the rotating detonation engine in complex geometries

This paper describes the development of a computational code REFLOPS USG (REactive FLOw solver for Propulsion Systems on UnStructured Grids) based on the Favre averaged Navier-Stokes equations with chemical reactions for semi-ideal multicomponent gas to predict the structure and dynamics of three-dimensional unsteady detonation as it occurs in the Rotating Detonation Engine (RDE). This work provides an overview of second order accurate in time and space finite volume method applied to conservation equations and its implementation on unstructured self-adaptive tetrahedral or hexahedral three-dimensional cell-centred meshes. The inviscid fluxes are given by the Riemann solver and stabilization is ensured by the proper limiters inherited from the TVD theory or gradient based limiters. The stiff equations of chemical kinetics are solved by use of implicit DVODE (Double precision Variablecoefficient Ordinary Differential Equation solver, with fixed-leading-coefficient implementation) routine or by explicit Chemeq2 routine. Additional improvements are incorporated into the code such as parallelization in OpenMP and implementation of NVIDIA CUDA technology. REFLOPS USG has become a fundamental numerical tool in the research of RDE at the Institute of Aviation in Warsaw, in frame of Innovative Economy project UDA-POIG.01.03.01-14-071 ‘Turbine engine with detonation combustion chamber’ supported by EU and Ministry of Regional Development, Poland. The simulations presented in this paper are based on inviscid or viscous multicomponent semi-ideal gas flow with chemical reactions. Due to high computational costs only simple chemical reaction mechanisms are used here

NUMERICAL TOOLS FOR THREE DIMENSIONAL SIMULATIONS OF THE ROTATING DETONATION ENGINE IN COMPLEX GEOMETRIES

This paper describes the development of a computational code REFLOPS USG (REactive FLOw solver for Propulsion Systems on UnStructured Grids) based on the Favre averaged Navier-Stokes equations with chemical reactions for semi-ideal multicomponent gas to predict the structure and dynamics of three-dimensional unsteady detonation as it occurs in the Rotating Detonation Engine (RDE). This work provides an overview of second order accurate in time and space finite volume method applied to conservation equations and its implementation on unstructured self-adaptive tetrahedral or hexahedral three-dimensional cell-centred meshes. The inviscid fluxes are given by the Riemann solver and stabilization is ensured by the proper limiters inherited from the TVD theory or gradient based limiters. The stiff equations of chemical kinetics are solved by use of implicit DVODE (Double precision Variablecoefficient Ordinary Differential Equation solver, with fixed-leading-coefficient implementation) routine or by explicit Chemeq2 routine. Additional improvements are incorporated into the code such as parallelization in OpenMP and implementation of NVIDIA CUDA technology. REFLOPS USG has become a fundamental numerical tool in the research of RDE at the Institute of Aviation in Warsaw, in frame of Innovative Economy project UDA-POIG.01.03.01-14-071 ‘Turbine engine with detonation combustion chamber’ supported by EU and Ministry of Regional Development, Poland. The simulations presented in this paper are based on inviscid or viscous multicomponent semi-ideal gas flow with chemical reactions. Due to high computational costs only simple chemical reaction mechanisms are used here

Three - dimensional numerical simulations of the combustion chamber of the rotating detonation engine

From 2010 Warsaw University of Technology (WUT) and Institute of Aviation (IoA) jointly implement the project under the Innovative Economy Operational Programme entitled ‘Turbine engine with detonation combustion chamber’. The goal of the project is to replace the combustion chamber of turboshaft engine GTD-350 with an annular detonation chamber. During the project, the numerical group that aims to develop computer code allowing researchers to simulate investigated processes has been established. Simulations provide wide range of parameters that are hardly available from experimental results and enable better understanding of investigated processes. Simulations may be also considered as a cheap alternative for experiments, especially when testing geometrical optimizations. In this paper the analysis of simulation results of the combustion chamber of the Rotating Detonation Engine (RDE) investigated at the IoA in Warsaw is presented. Primarily, REFLOPS USG which has become a fundamental numerical tool in the research of the RDE at the IoA is briefly described and governing equations and numerical methods used are shortly presented. Some aspects of numerical simulations of the RDE, related to selection of combustion mechanism, and an initiation of rotating detonation are provided. Secondly, results of simulations of inviscid gas with numerical injectors of hydrogen are compared with available experimental results. Three different wave patterns are identified in numerical solution and briefly described. Results of simulations are compared to experimental results in combustion chamber. Results presented in this paper are part of the project UDA-POIG.01.03.01-14-071 ‘Turbine engine with detonation combustion chamber’ supported by EU and Ministry of Regional Development, Poland

Resistojet thruster with a power system based on supercapacitors

This paper presents research into a resistojet model that can be powered by supercapacitors for satellite propulsion applications. The performance of the system, calculated including a preliminary study of mass and power budget, shows that this solution has potential for a certain range of space missions. The main problem when designing a pulsed resistojet is the compromise between the thermal capacity of the resistojet and the heat transfer efficiency of the device. When the heater is used in pulsed mode, it should have low mass and thermal capacity in order to reduce the energy required to heat the devices. On the other hand, the main technical restriction in resistojet thrusters is heat transfer due to the laminar regime of the flow in the heater. The heat transfer area should be as large as possible, but the mass of the device limits any such increase in area. In this research several design options were considered in an attempt to find the optimal solution. After research on the oscillating element and porous heater, capillary tubes directly heated by the current were determined to be the most effective solution. A power supply based on supercapacitors was constructed. It consists of 30 supercapacitors of 300 F each, connected to deliver 70 V of voltage, 10F of total capacitance and maximum peak power of 5 kW. Research for three different gases – ammonia, propane and butane – was conducted and the results are presented in this paper

Dynamic analysis of the chamber for testing mining devices in the explosion conditions

W artykule przedstawiono przebieg i wyniki analizy obciążeń działających na płaszcz komory ciśnieniowej przeznaczonej do badania urządzeń górniczych w atmosferach gazów palnych w warunkach wybuchu. Przeprowadzono analizę zależności maksymalnego ciśnienia wywołanego wybuchem od rodzaju mieszanin gazowych i charakteru ich spalania. Określono maksymalne naprężenia występujące w płaszczu komory podczas wybuchu i wymagania wytrzymałościowe materiału konstrukcyjnego przeznaczonego do jego budowy.The article presents the course and results of the analysis of loads influencing the shell of the pressure chamber meant for testing mining devices in the combustible gas atmospheres in the explosion conditions. The analysis of the dependence of maximum pressure caused by the explosion on the type of gaseous mixtures and the character of their combustion was carried out. The maximum stresses occurring in the chamber's shell during the explosion and resistance requirements of the engineering material meant for building the shell were determined

Experimental and numerical study of the rotating detonation engine in hydrogen-air mixtures

Experimental and numerical study of rotating detonation is presented. The experimental study is focused on the evaluation of the geometry of the detonation chamber and the conditions at which the rotating detonation can propagate in cylindrical channels. Lean hydrogen-air mixtures were tested in the experiments. The pressure measured at different locations was used to check the detonative nature of combustion. Also, the relationship between detonation velocity and operation conditions is analyzed in the paper. The experimental study is accompanied with numerical analysis. The paper briefly presents the results of two-dimensional (2D) numerical simulation of detonative combustion. The detonating mixture is created by mixting hydrogen with air. The air is injected axially to the chamber and hydrogen is injected through the inner wall of the chamber in radial direction. Application of proper injection conditions (pressure and nozzle area) allows establishing a stable rotating detonation like in the experiments. The detonation can be sustained for some range of conditions which are studied herein. The analysis of mean parameters of the process is provided as well. The numerical simulation results agree well with the experiments