Moisture Content Prediction Model And Experimental Verification Of Aquatic Feed Based On The Exponential Function Using CFD Techniques

Feed industry is an key industry for China economy.Because of the high moisture content of the feed after the expansion treatment,the processing of the feed can not be separated from the drying technology of feed.The moisture content of feed is one of the important indexes of feed processing quality.Reasonable drying parameters can reduce the moisture content of feed,improve the stability of feed,and prolong the storage period of feed.Temperature is an important drying process parameter.Which is closely related to the water loss rate of materials.In recent years,selecting reasonable drying process parameters efficiently has become a research hotspot by reasonable mathematical model and algorithm of moisture predictionThis paper aims to solve the problems of low drying efficiency,high energy consumption,and low drying quality in the drying process of aquatic feed.This paper use three kinds of aquatic feed(including,crabs feed,yellow catfish feed,and tilapia feed)as experimental samples In this paper,computational fluid dynamics(CFD)and experimental measurement are combined.It is verified that CFD can accurately simulate the airflow velocity field of the drying room.In this paper,the mathematical model of exponential moisture prediction is established,and the influence of drying temperature on the water loss rate of materials in the drying process is studied.Which provides a theoretical basis for the selection of drying temperature of aquatic feed.(1)This paper,establish a experimental drying platform based on the actual production of the dryer,using FLUENT software for numerical simulation.Firstly,the simplified three-dimensional model of the experimental drying platform is established.Secondly,the simplified model is meshed,the model parameters and boundary conditions are set,and the calculation is started.Finally,the air vector diagram,the airflow velocity cloud diagram and the simulated airflow velocity values inside the experimental drying platform are obtained by the post-processing software.(2)Using three kinds of aquatic feeds,(including,crabs feed,yellow catfish feed,and tilapia feed)to measure the airflow velocity on the experimental drying platform at different fan frequencies(25Hz,30Hz,35Hz).It is found that CFD can effectively simulate the distribution of airflow velocity field inside the dryer,and the airflow velocity values inside the dryer increases with the increase of fan frequency by comparing the simulated airflow velocity values with the experimental airflow velocity values(3)An exponential mathematical model of airflow velocity,drying temperature and residual moisture content of materials in drying room was established.Then three kinds of aquatic feeds were dried at a constant temperature(90?,105?,120?,135?).Based on the experimental data of constant temperature,the three temperature parameters(k,y,n)of the exponential mathematical model are calculated by the least square method.Then the correlation coefficient(R2),chi square value(?2)and root mean square error(RMSE)are calculated to evaluate the fitting degree.Using multi-gradient temperature experiment(90?-105?-120?,105?-120?-135?)to verify the feasibility of the model.The experimental results are compared with the simulated results of the model.The fitted correlation coefficient(R2),chi square value(?2)and root mean square error value(RMSE)are calculated.The results show that the model can effectively predict the influence of temperature variables on the moisture content of materials at the constant.airflow velocity.(4)In order to analyze the durability of three kinds of dried aquatic feeds,the experiment of measuring the flour content and dusting rate was carried out.The results showed that the durability of the three materials dried at 120? accord with the national standard.The order of durability of three kinds of aquatic feeds was:crab feed>tilapia feed>yellow catfish feed.Using SEM to observe the microstructure of yellow catfish feed and tilapia feed.The results showed that both yellow catfish feed and tilapia feed were porous structure.