Enhancement Of Ultrasonic And TiO₂ Nanoparticles On The Characteristic Of NH₃-H₂O-LiBr Solution Ammonia Absorbed

Adding LiBr to NH₃-H₂O solution can reduce the phase equilibrium pressure of the solution and increase the mass fraction of ammonia in the gas phase,thus improving the occurrence characteristics of the ammonia absorption refrigeration system.However,the presence of LiBr in the liquid phase can inhibit the absorption process of the system.This project aims to improve the absorption characteristics of ammonia in ternary solution by introducing ultrasonic oscillation and TiO₂nanoparticles,so as to compensate for the absorption inhibition caused by LiBr.A typical bubbling absorber in ammonia absorption refrigeration system was taken as the research object,and the NH₃-H₂O-LiBr ternary solution bubbling absorption experimental platform was built to obtain the ammonia absorption characteristic data under TiO₂nanoparticles,ultrasonic oscillation,and their synergy.Simultaneously,based on the mathematical model of bubble absorption of binary ammonia water,the source term of mass,momentum,energy and component caused by the interaction of nanoparticles,ultrasonic oscillation and the solution was introduced.Then the mathematical model in NH₃-H₂O-LiBr ternary solution was established by physical property modification and verified with experimental data.Based on the validation model,the enhancement of different strengthening methods on ammonia bubble absorption of different base fluids was analyzed.In addition,the enhancement of ultrasonic,nanoparticles and their synergistic effects under different operating conditions（inlet pressure,cooling water temperature,initial ammonia concentration）was explored through variable parameter analysis.The ammonia absorption of binary solution without any strengthening method is regarded as the benchmark.When nanoparticles act alone,as the concentration of nanoparticles is 0.1wt%,effective absorption ratio increases by 4%.When ultrasonic alone is applied,the effective absorption ratio of ammonia increases by 11%as the ultrasonic frequency is 68k Hz.When ultrasonic and nanoparticles act together,the effective absorption ratio of solution increases by 22%as the ultrasonic frequency is68k Hz and nanoparticle concentration is 0.1wt%.The higher the inlet pressure of the absorber,the higher the temperature of the base liquid,the higher the ammonia concentration of the base liquid,and the greater improving intensity the adverse absorption caused by LiBr with the combined effect of ultrasonic and nanoparticles.