Numerical Simulation And Experimental Verification Of Engine Dry Ice Cleaning

During the working process of the aero-engine,a large amount of airborne soot,salt and other particles will be sucked into the culvert,these particles will accumulate on the blade surface and cylinder wall area of the compressor,which will increase the thickness and roughness of the airflow field wall surface layer,leading to larger airflow flow loss,airflow separation,etc.,which will seriously occur over temperature,wheezing failure,affecting flight safety.The existing aero-engine cleaning technology uses water washing in the wing,the process is complex and there are residues,cleaning agents will also cause environmental pollution.This thesis explores the use of dry ice particle cleaning technology to clean the engine compressor blade.Through simulation and self-built engine compressor dry ice cleaning test platform,dry ice cleaning of the compressor blade research,the main work and results.(1)Based on the dry ice cleaning mechanism and engine scale adhesion mechanism,analyze the dry ice cleaning engine compressor scale accumulation mechanism.The dry ice cleaning mechanism is mainly dry ice impact,high speed air blowing,liquid carbon dioxide dissolution of organic matter and thermal impact,breaking the intermolecular hydrogen bonding and van der Waals forces,as well as the mechanical interlocking and riveting cooperation generated by the uneven surface of the blade.(2)Based on the hydrodynamic theory,FLUENT software is used for numerical simulation to study the nozzle jet flow field and dry ice particle motion trajectory.The velocity and trajectory of dry ice particles were obtained under different jet pressures,and it was found that:when the total inlet pressure was 105000 pa,the movement of dry ice particles was closer to the real internal situation of the cold-running press;when the dry ice particles were more dispersed within 0.45 m from the nozzle outlet,which provided a reference for the selection of reasonable decontamination parameters for the subsequent dry ice cleaning test.(3)Design and build a dry ice cleaning test platform for engine compressor consisting of stable pressure supply system,dry ice cleaning machine,dry ice feeding device and engine compressor,and conduct dry ice cleaning test,systematically study the influence law of dry ice mass flow rate,jet angle and compressor speed on the cleaning effect of compressor blade;design and conduct orthogonal test to determine the best combination of process parameters.The results show that the dry ice particle cleaning will not damage the metal surface of the compressor blade and will not affect the bonding strength of the blade coating.(4)Based on the fluid dynamics model and FLUENT analysis software,the movement of dry ice particle cleaning inside the compressor was studied.The results show that the larger the compressor cold rotation speed,the better the dry ice cleaning effect;dry ice particles cleaning the compressor blade area is mainly the back of the compressor blade and the leading edge of the blade basin part,the simulation results and cleaning test results are basically consistent with the situation.