Design Calculation And Numerical Simulation Of New Type Button Turbine Engine

With the development of MEMS processing technology,the power devices are miniaturized gradually.As a new type of power device,micro turbojet engine has been studied widely in recent years.It has been widely used in aviation,aerospace,shipbuilding,power generating units and so on.The development of the size of micro turbojet engine is from centimeter to millimeter level,the new button type turbojet engine as a millimeter level turbojet engine,the diameter size of the engine reached millimeter level,machining accuracy is even up to the micro nano scale.A new type of button turbine engine is similar with the conventional micro turbine engine,it uses centrifugal turbine structure,resulting in most of the power in the 10~100W range.Compared with conventional micro turbojet engine,the new button type turbojet engine(BTE)has the following characteristics: structure is more compact;the higher thrust to weight ratio;noise is lower;the relative fuel consumption rate is smaller.Although its volume confined,in the case of small scale,the aerodynamic loss,heat transfer problems and difficult manufacturing and processing will restrict the performance of the engine.But,BTE as a new high energy storage of power plant,still has a great potential as future portable energy,spacecraft attitude and orbit control energy device.When a plurality of micro turbojet engines are connected in parallel,it can be used as a propeller to provide power for small Unmanned Aerial,tactical missile,vehicle turbocharger,and other space vehicles.This topic is based on the researches of micro turbojet engine domestic and international,independently designed an ultra millimeter round button type turbojet engine,this engine is 20.5mm in diameter,4mm in thickness,use Si or Si C for material,fuel for hydrogen or methane.Physical processing relies on MEMS plasma etching technology,divided into different levels of processing,and finally through the bonding assembly.Using the modern mature numerical simulation technology for this micro turbojet engine components,got some important performance parameters.In addition,due to the limitation of the MEMS materials processing and experimental conditions,the numerical simulation results are compared with the experimental data of other micro turbine engine.The main research contents include the following aspects:(1)According to the design requirements,done some thermodynamic calculations,through multiple calculations,got the micro turbine jet engine design thermodynamic parameters and each working state’s thermodynamic parameters,these parameters can be providing some reference data for the design of engine.(2)Designed a miniature centrifugal compressor for micro turbojet engine;then simulated the steady working process,the results of analysis met the compressor design reasonably,when the speed is 120000 rpm,the performance parameters met design requirements.(3)According to the performance requirement of engine,six independent combustion chambers were designed,the structure and size of micro combustor were determined by thermodynamic calculation.Micro combustor steady combustion process was simulated,got three kinds of working state of the combustion chamber’s main performance parameters,combustion efficiency varied with the variation of the speed,the combustion efficiency characteristic curve,the total pressure recovery coefficient with changes in the relationship between the air flow and exit radial combustor temperature distribution,and analyzed variety factors that affect the performance of combustion chamber.The simulation results showed that there were obvious recirculation zones in the the left and right upper part of combustor inlet,which can ensure the fuel mixing and combustion efficiently.Compared with other micro turbine engine experiments,proving the rationality of the design of combustion chamber.(4)Designed a miniature radial turbine and integrated simulation with the nozzle,got turbine’s air pressure,temperature and velocity distribution under three different working conditions,though analyzed the performance of the turbine,the important parameters of the gas at the nozzle exit are obtained.Finally conbined the front research,completed the turbojet engine overall performance of numerical simulation,obtained design performance parameters which met the design requirements,thus validating the engine design methods,illustrating the feasibility of design method adopted in the design process.Therefore provided a reference for this type of micro turbine jet engine.