Numerical Research Of Impact And Deposition Process Between Catalytic Particle And Flue Gas Turbine Blade

As an important equipment in energy recovery system used for catalytic cracking unit,flue gas turbine has an advantage in the area of energy saving and environment protection.As we all know,the third cyclone separator can not separate all catalytic particles with a 100%efficiency.For this reason,we can find some catalytic particles entrainment at the inlet of flue gas turbine which leads to serious deposition and fouling.In this article,we focus on the process of collision and deposition between catalytic particles and flue gas turbine blades.First of all,we simulate the gas flow field of flue gas turbine.The vane cascade is the most important place where thermal energy and pressure energy of high temperature flue gas are changed into kinetic energy.The blade cascade is the place where kinetic energy of high temperature flue gas are changed into mechanical energy of flue gas turbine blade.Secondly,we calculate the magnitude of drag force,Corioli and inertial centrifugal force,the resultant force of gravity and buoyancy,electrostatic force by theoretical formula.And we study the effects of Corioli and inertial centrifugal force,the resultant force of gravity and buoyancy on the particle movement in flue gas turbine.The result is that,Corioli and inertial centrifugal force(10^-1110^-7N)has an important effects on particle movement,while the resultant force of gravity and buoyancy has little effects on particle movement.Thus,in the process of simulation of particle movement in flue gas turbine,the force which has a smaller order of magnitude than 10^-11 can be ignored in order to cut down the period of numerical simulation,while the force which has a larger order of magnitude than 10^-11 must be considered.Finally,we calculate the simplified collision formula between catalytic particle and flue gas turbine blade by C code procedure.We judge the feasibility of the four most popular impact theories?JKR?Hertz?BD?DMT?for the case in this article and we study the effects of particle diameter and gas flow on particle deposition by the deposition criteria we deduce.The result is that,the JKR theory is more suitable than other three impact theories to describe the process of collision between catalytic particles and flue gas turbine blades.The particles whose diameter is between 1?m and 5?m are mostly apt to deposit on the surface of blades,and the particles whose diameter is larger than 10?m have an obvious effect on flue gas turbine because of its larger mass.And the deposition deteriorate with the increment of flue gas flow and running time.