Research On Vacuum Degree Characteristics Of The Jetting Vacuum Generator

Vacuum adsorption system of the jetting vacuum generator as an important handling technology,pneumatic technology application domain was more and more widely.But jetting vacuum generator has a common regularity of vacuum degree become the maximum in supply pressure is 0.45 MPa,while the vacuum degree will fall more than 0.45 MPa.And in the process of work must be continuous to supply quantitative gas and air consumption is very large.Therefore,this paper analysis the reasons of the decrease of the vacuum degree,and obtain the influence of structural parameters about vacuum degree through simulation,the maximum vacuum degree reaches the maximum value in the lower supply pressure so that saving the air consumption.Because the vacuum generator was to work according to the principle of Laval nozzle,first of all,this paper analyses the working principle of Laval nozzle its nozzle within several flow state,research flow status different in upstream and downstream pressure ratio in the nozzle.Using the fluent software carry on the numerical simulation with change the Laval nozzle contraction or expansion Angle,the exit velocity basically remain unchanged.But change the nozzle exit area to throat area ratio,the exit velocity obvious change,so the area ratio is the main factors influencing the Laval nozzle accelerating,nozzle exit velocity is determined by the only area ratio.By the formula through the Laval nozzle air consumption,air consumption is proportional to the supply pressure,reducing the value of the supply pressure can reducing the consumption of the air,so as to realize energy saving.Secondly,vacuum generator the internal flow field numerical simulation use of fluent software and analyzed the cause of vacuum degree decline,and the vacuum degree of vacuum generator curve change under different parameters which explore the vacuum generator parameters on the maximum vacuum drop point and the influence of the peak.Finally,the vacuum generator for the design of the different parameters using 3D printing technology,build test bench and study on the parameter change on the influence of its performance through the experiment.Experimental results show that the decrease of the diameter of the expansion or the size of the area ratio can make the vacuum degree reach maximum pressure in the lower pressture.Nozzle diameter was 1 mm,for example,in the outlet diameter is 1.8 mm,expansion pipe diameter is 2.2 mm,to achieve maximum vacuum degree was 0.3 MPa which the biggest is 86 kPa,reducing the maximum vacuum pressure value and equivalent to reduce the air consumption.