Численное моделирование возникновения колебаний давления в термоакустическом преобразователе

The article describes the features of numerical simulation of acoustic oscillation excitation in the resonators with a foam insert (regenerator) to study the excitation of thermo-acoustic oscillations in the circuit of small-sized engine model on the pulse tube.The aim of this work is the numerical simulation of the emerging oscillations in thermoacoustic engine resonator at the standing wave. As a basis, the work takes a thermo-acoustic resonator model with the open end (without piston) developed in DeltaEC software. The precalculated operation frequency of the given resonator model, as a quarter of the wave resonator, is ν = 560 Hz.The paper offers a simplified finite element resonator model and defines the harmonic law of the temperature distribution on regenerator. The time dependences of the speed and pressure amplitude for the open end of the resonator are given; the calculated value of the process operating frequency is approximately equal to the value of the frequency for a given length of the resonator. Key findings, as a result of study, are as follows:1. The paper shows a potential for using this ESI-CFD Advanced software to simulate the processes of thermal excitation of acoustic oscillations.2. Visualization of turbulent flow fluctuations in the regenerator zone extends the analysis capability of gas-dynamic processes.3. Difference between operating frequency of the process simulated by ESI-CFD Advanced and frequency value obtained by analytical methods is about 4%, which is evidence of the model applicability to study the acoustic parameters of thermo-acoustic transducers. Experimental results have proved these data.В статье рассмотрены особенности численного моделирования процесса возбуждения акустических колебаний в резонаторах с пористой вставкой (регенератором) для исследования процесса возбуждения термоакустических колебаний в контуре модели малоразмерного двигателя на пульсационной трубе. Предложена упрощенная конечно-элементная модель резонатора и определен гармонический закон распределения температуры на регенераторе. Приведены временные зависимости скорости и амплитуды давления для открытого конца резонатора, расчетное значение рабочей частоты процесса приблизительно равно значению частоты для заданной длины резонатора. Полученные результаты позволяют судить о правильности выбора схемы дискретизации в ESI CFD ACE для учета неравновесных процессов тепломассообмена в области регенератора. результаты численного моделирования необходимо расширить с целью учета реальных особенностей конструкции двигателя на пульсационной трубе. DOI: 10.7463/aplts.0615.082964

Thermodynamic calculation of the turbofan engine [Электронный ресурс] : methodical instructions for course work

Используемые программы: Adobe Acrobat.Труды сотрудников Самар. ун-та (электрон. версия)

Development of Universal Exergy Analysis to the Selection of Cryogenic Cooling System

Efficiency is one of the most important parameters that apply to the cooling system. This paper describes a development of universal methodology to evaluate the effectiveness of cryogenic cooling systems. The problem of the lack of a universal method of comparison of cryogenic cooling systems was solved. This was achieved by creating a universal method of exergy analysis. In addition, as an example were examined three of the cooling system, which applies the universal exergy analysis. Basic universal parameters that characterize cooling system level of sophistication were defined, as well as main calculated. The result of this study is a new universal method of exergy analysis, which can be used to select a cryogenic cooling system

Development of Universal Exergy Analysis to the Selection of Cryogenic Cooling System

Efficiency is one of the most important parameters that apply to the cooling system. This paper describes a development of universal methodology to evaluate the effectiveness of cryogenic cooling systems. The problem of the lack of a universal method of comparison of cryogenic cooling systems was solved. This was achieved by creating a universal method of exergy analysis. In addition, as an example were examined three of the cooling system, which applies the universal exergy analysis. Basic universal parameters that characterize cooling system level of sophistication were defined, as well as main calculated. The result of this study is a new universal method of exergy analysis, which can be used to select a cryogenic cooling system

Optimizing the Thermoacoustic Pulse Tube Refrigerator Performances

The article deals with research and optimization of the thermoacoustic pulse tube refrigerator to reach a cryogenic temperature level. The refrigerator is considered as a thermoacoustic converter based on the modified Stirling cycle with helium working fluid. A sound pressure generator runs as a compressor. Plant model comprises an inner heat exchanger, a regenerative heat exchanger, a pulse tube, hot and cold heat exchangers at its ends, an inertial tube with the throttle, and a reservoir. A model to calculate the pulse tube thermoacoustic refrigerator using the DeltaEC software package has been developed to be a basis for calculation techniques of the pulse tube refrigerator. Momentum, continuity, and energy equations for helium refrigerant are solved according to calculation algorithm taking into account the porosity of regenerator and heat exchangers. Optimization of the main geometric parameters resulted in decreasing temperature of cold heat exchanger by 41,7 K. After optimization this value became equal to 115,01 K. The following parameters have been optimized: diameters of the feeding and pulse tube and heat exchangers, regenerator, lengths of the regenerator and pulse and inertial tubes, as well as initial pressure. Besides, global minimum of temperatures has been searched at a point of local minima corresponding to the optimal values of abovementioned parameters. A global-local minima difference is 0,1%. Optimized geometric and working parameters of the thermoacoustic pulse tube refrigerator are presented

Numerical Simulation of Pressure Fluctuations in the Thermo-acoustic Transducer

The article describes the features of numerical simulation of acoustic oscillation excitation in the resonators with a foam insert (regenerator) to study the excitation of thermo-acoustic oscillations in the circuit of small-sized engine model on the pulse tube.The aim of this work is the numerical simulation of the emerging oscillations in thermoacoustic engine resonator at the standing wave. As a basis, the work takes a thermo-acoustic resonator model with the open end (without piston) developed in DeltaEC software. The precalculated operation frequency of the given resonator model, as a quarter of the wave resonator, is ν = 560 Hz.The paper offers a simplified finite element resonator model and defines the harmonic law of the temperature distribution on regenerator. The time dependences of the speed and pressure amplitude for the open end of the resonator are given; the calculated value of the process operating frequency is approximately equal to the value of the frequency for a given length of the resonator. Key findings, as a result of study, are as follows:1. The paper shows a potential for using this ESI-CFD Advanced software to simulate the processes of thermal excitation of acoustic oscillations.2. Visualization of turbulent flow fluctuations in the regenerator zone extends the analysis capability of gas-dynamic processes.3. Difference between operating frequency of the process simulated by ESI-CFD Advanced and frequency value obtained by analytical methods is about 4%, which is evidence of the model applicability to study the acoustic parameters of thermo-acoustic transducers. Experimental results have proved these data