Design And Experiment Of Bionic CDPF Based On The Oral Structure Of Basking Shark

Diesel engine has become one of the main power sources with its many advantages and is widely used in various transportation and engineering machinery.However,the particulate matter（PM）produced by diesel engine combustion has caused great harm and threat to the natural environment and human health.In order to reduce the emission of diesel particulate matter,the Diesel Particulate Filter（DPF）has become a necessary device in the exhaust system of diesel engines.In this paper,a Catalytic Diesel Particulate Filter（CDPF）with bionic structure is investigated by taking the basking shark oral cavity as the research object and combining the advantages of calcium titanite in catalytic oxidation of diesel exhaust particulate matter.The main research contents and results of this paper are as follows:Using wood powder with natural pore structure,LaCoO₃ with porous structure was prepared by using wood powder as a template and combined with sol-gel method,and the samples were characterized using X-ray diffraction,Fourier transform infrared spectroscopy,scanning electron microscopy,and N₂ adsorption desorption.The results showed that the formation of the chalcogenide phase started at the calcination temperature of 600°C.The porous La Co O₃ replicated the structural features of wood flour from macroscopic to tubular cells and formed a porous structure.As the calcination temperature increased,the specific surface area and porosity of porous La Co O₃ decreased,while the average pore size increased.The morphological characteristics of the oral cavity,which plays a key function in the filter feeding process of basking shark,were used as a model to design the bionic structure of CDPF.The mathematical model of CDPF was established based on gas-solid two-phase flow theory and porous media theory,and the gill rake thickness,oral opening angle and gill slit inclination angle were selected as simulation factors,and the pressure drop was used as the evaluation index to conduct numerical simulations of single-factor and orthogonal designs,respectively.The flow field inside the CDPF was simulated using Fluent,a commercial computational fluid dynamics software,to study the influence law of structural parameters of the CDPF on the pressure loss inside the particle trap.The results show that the optimal structural parameters of the CDPF are the oral tension angle of 1.5°,the gill crack inclination angle of 60°,and the filling thickness of 6 mm.A relevant simulated test rig and diesel engine test rig were built to perform filtration efficiency and pressure drop tests on CDPF.Thermogravimetric tests were conducted on simulated particulate matter and diesel particulate matter to verify the catalytic oxidation performance of the catalyst.In the simulation test,the concentration of simulated particulate matter and the flow rate of simulated gas were used as the control variables respectively.The results show that when the simulated gas flow rate is fixed,the purification efficiency remains basically the same with the gradual increase of the simulated particulate concentration,which is about 82%;the pressure drop increases with the increase of the simulated particulate concentration and the simulated gas flow rate.When the particle concentration is constant,the purification efficiency decreases slightly with the increase of gas flow rate.The pressure drop increases with the simulated particulate concentration and the simulated gas flow rate.The bench test was conducted to analyze the effect of purification efficiency and pressure drop on the diesel engine under various operating conditions,and to verify the feasibility and effectiveness of CDPF for exhaust gas particulate purification by considering the speed and load conditions under actual operating conditions.The results of the bench test show that as the load increases,the concentration of exhaust gas particles increases and the purification efficiency of the device increases.The pressure drop increases with the increase of engine speed and load.In thermogravimetric tests,porous LaCoO₃ showed excellent catalytic performance for both simulated simulated particulate matter and diesel particulate matter,with a temperature point T₁₀ of 313°C corresponding to 10%conversion of simulated particulate matter and 220°C corresponding to 10%conversion of diesel particulate matter.