Simultaneous Three-dimensional Measurement Of Temperature And Velocity In Swirl Combustion

The latest research focus in the field of combustion diagnosis and flow field display have extented to develop a new method for combustion measurement and display that meets the requirements of non-intrusive,multi-parameter simultaneous measurement,quantitative calculation,multi-dimensional visualization.Temperature and velocity,as two important parameters reflecting chemical reaction and flow field transport,affect the combustion mechanism and combustion dynamics characteristics,which have become the key to jointly characterize and diagnose the combustion processes.Based on the principle of three-dimensional particle image velocimetry and deflection tomography,this paper combines three-dimensional particle image velocimetry technology with deflection tomography temperature measurement technology to establish a method and system that can measure the three-dimensional temperature and velocity of complex combustion at the same time.The non-premixed swirl combustion system is designed and constructed.Methane is used as a fuel to produce a swirling flame.The tracer particle generator is designed to spread the tracer particles evenly throughout the combustion flow field.Based on the theory of particle image velocimetry and the theory of deflection tomography,two measurement techniques are combined to construct a measurement system of three-dimensional temperature and velocity in complex combustion.The multi-parameter simultaneous measurement experiment o f swirling combustion was carried out to obtain the moiré fringe pattern and the tracer particle map.According to the experimentally obtained moiré fringe pattern,the projection data is extracted using the fringe tracking method.The two-dimensional temperature distribution of different sections of the swirling combustion flow field is reconstructed by the deflection angle compression sensing correction algorithm.Visualization toolkit is used to reconstruct and visualize the three-dimensional temperature field of the swirling combustion flow field.According to the obtained flow field tracer particle map,the volumetric three-dimensional velocity calculation software is used to undergo two-dimensional plane particle matching,three-dimensional space particle matching,three-dimensional space velocity vector calculation,three-dimensional space velocity visualization.The reconstruction and visualization of the three-dimensional velocity field of the swirling combustion flow field is realized.The reconstruction results show important information inside the flow field such as three-dimensional temperature distribution,three-dimensional velocity vector distribution,and vorticity.Error analysis of the measurement system was performed using a thermocouple and a hot wire anemometer.Further,under different working conditions,the influence of the position of the swirler vane on the velocity and vorticity and the influence of the air flow rate on the velocity evolution of the combustion are investigated.The methods and technical achievements of this research will provide basic scientific basis and practical technical support for complex combustion mechanism research and new burner design.