Design Of Feed Pneumatic Conveying System And Study On Erosion Wear Of Pipe In Piggery

In the process of modern large-scale pig breeding,feed transportation is an essential link,and there are many problems to be solved in the practical application of dry feed line and liquid feed line.But,pneumatic conveying has been paid more and more attention to by pig breeding industry in recent years due to its advantages of strong conveying capacity,long conveying distance,low crushing rate and high level of disease prevention and control,etc.However,pneumatic conveying also has problems in its application.When the feed passes through the elbow in the conveying process,it will constantly impact the outer wall of the elbow,which causes serious erosion wear of the elbow.The long-term erosion wear of the elbow may lead to pipe damage and induce food safety accidents.Therefore,it is of great practical significance to design pneumatic feed conveying system and carry out research on reducing the erosion wear of elbow pipe.Based on this,in order to meet the feed supply of ten thousand pigs produced annually in modern large-scale pig breeding as the goal,this paper carried out the design of feed pneumatic conveying system and test device,and carried out the related conveying performance tests.In view of the problems caused by erosion wear of elbow pipe,a new type of elbow pipe is proposed.The erosion wear of the ordinary and new elbow is compared and analyzed by using computational fluid dynamics(CFD)and discrete phase model(DPM).And based on the orthogonal test method,the effects of the operating parameters of the device on the erosion wear of two kinds of elbow pipes were studied,and the optimal combination of operating parameters was obtained,which was used to evaluate the optimization effect of the erosion wear of elbow pipe.The main contents and conclusions of this study are as follows:Firstly,the feed pneumatic conveying system and test device were designed to meet the daily feed consumption of modern large-scale pig breeding of ten thousand pigs per year.The main transportation performance tests,such as conveying capacity,pipeline pressure drop and crushing rate,were carried out.After testing,it is found that the conveying performance of the test device meets the design requirements.Secondly,The pressure drop gradient and the air velocity at the outlet of the feed conveying pipeline were studied based on the feed pneumatic conveying test device,and the CFD-DPM method was used to carry out the numerical simulation research on the feed conveying pipeline.Through the comparative analysis of the test data and the simulation data,it is found that the test values of pressure drop gradient and air velocity at the outlet of the pipeline have a high degree of fit with the simulation values,which indicates that the CFD-DPM numerical simulation method used in this paper is reliable.Then,in view of the serious erosion wear of the elbow caused by gas-solid two-phase flow in feed conveying pipeline,a new type of elbow with auxiliary airflow outside the elbow is presented.The flow field distribution,particle movement and erosion wear of the ordinary and new bending pipes were compared and analyzed by using the above simulation method.Furthermore,the influence of air inlet velocity,particle mass flow rate and particle size on the erosion wear of two bending pipes were further studied.It is found that the erosion wear rate of the new type of elbow is smaller than that of the ordinary elbow,and the erosion wear of the new type of elbow can be effectively reduced by reducing the mass flow rate and particle size of the elbow.Finally,based on the above research,in order to further master the influence law of operating parameters on the erosion wear of elbow,the optimal combination of operating parameters with the minimum erosion wear rate of the new elbow was obtained based on the orthogonal test method,and the numerical simulation was carried out under the condition of the operating parameters.The average erosion wear rate of the new-type elbow is 11.1% lower than that of the ordinary elbow.On the one hand,this study can provide a design method of pneumatic feed conveying system for modern large-scale pig breeding.On the other hand,it also provides an effective method to reduce the erosion wear of elbow pipe for gas-solid two-phase flow transportation.The research results can provide reference for the application and promotion of pneumatic conveying in modern large-scale pig breeding and other animal husbandry industries.