Study On Mechanism And Experimental Of Vortex Flow Washing Technology

In agricultural products and food processing washing is a very important link.There is still a big gap between the fruits and vegetables washer produced in our country and foreign`s currently,so it`s significant to develop a new type of fruits and vegetables washer.The research and development of fruits and vegetables washer is focused on high efficiency and energy saving.In this paper the vortex flow washing method was selected,and the single、double vortex flow washer was designed.The dynamic characteristics of single、double vortex flow washing were studied through theoretical methods and numerical analysis,and the effect of vortex flow washing fruits and vegetables through experimental was also studied in this paper, the specific works were as follows:1.The vortex flow washing prototype was designed and fabricated,and the flow loss and force acting on the material were calculated.The flow loss in double vortex flow is smaller,but the jet impact force is bigger in single vortex flow.The preliminary experimental was studied through washing prototype.The vortex flow washing is more suitable for some of the smaller volume of fruits,leafy vegetables,and a small volume of tuber vegetables.2.The dynamic characteristics of single、double vortex flow washing in washer model were studied with CFD.The rationality of setting boundary conditions was verified through two phase flow method,and the numerical results was validated by particle traccer experiments.Based on numerical results the influencing factors were analyzed,includes the total inlet flow Q、position of the transverse jet nozzles H、height difference between longitudinal and transverse jet nozzles h、ow ratio R and angle θ,and the results of numerical analysis in single、double vortex flow were compared under the same conditions.and the mechanism of vortex flow washing and its impact on the structure and performance of the washing prototype were also revealed. The results show that:the boundary condition setting is reasonable.Q and H have little effect on the flow field in washing tank,and h has some influence on the formation of double vortex flow.The flow ratio has a great influence,and the formation of vortex flow is good in the tank when R=2.The angle θ has great impact on the formation of double vortex flow,and the double vortex flow is better when θ is small.Under the same conditions,the turbulent motion in single vortex flow is stronger,but the flow field distribution in double vortex flow distribution is better.3.The effect of vortex flow washing fruits and vegetables was studied by experiments,and the mainly evaluating index was the number of colonies in samples after washing.The factors impacted on the effect of single、double vortex washing small brassinca chinensis and cherry tomatoes were analyzed through response surface experiments,including washing time、amount of material and flow ratio.Results show that to allow the material forming a vortex flow,you need to select the flow washing method according to the characteristics of material.The effect of double vortex flow washing is better than single vortex flow washing.The most obvious factor is washing time,and the interaction between washing time and amount of material is significantly when washing small brassinca chinensis.The interaction between washing time and flow ratio is significantly when washing cherry tomatoes.