Experimental Study On Dynamic Side Pressure Of Silo Wall Discharge

The dynamic pressure of the silo is greater than the static pressure is an indisputable fact,but the causes of dynamic pressure increase are complex,have long been in the exploratory stage.So far,there is no mature design theory.In particular,the theory of cylinder wall discharge is more scarce.Therefore,the pressure of material flow on the wall side of the cylinder wall is studied,which is of great theoretical and practical value.The paper relied on the National Natural Science Foundation of China project: <Study on Dynamic Overpressure Mechanism of Silo Based on Energy Conversion of Loading and Unloading Process(51578216)>.The main contents of this paper are:(1)Combined with engineering examples to produce silo model,the pressure sensor was calibrated by the test and was installed in the set position of the inner wall of the silo.(2)Static pressure and dynamic pressure tests were used for silos with different aspect ratios(1.1 and 2.2)using unilateral and bilateral discharge methods.The maximum static pressure value of each measuring point was measured and compared with the theoretical value.The dynamic side pressure in the discharge process was determined.The overpressure coefficient was calculated according to the test results.(3)The results showed that the maximum overpressure coefficient of Shallow silo was located at the depth of 0.2m,and the value was 1.57.The maximum overpressure coefficient of deep silo occurs in the depth of 0.4m,the value was 1.74.In the process of double discharge,the maximum overpressure coefficient of Shallow silo was 0.2m,the value was 1.51.The maximum overpressure coefficient of deep silo was 0.4m,the value was 1.58.Thus,the maximum overpressure coefficient of shallow silo is smaller than the deep silo,and the unilateral discharge overpressure coefficient is bigger than the bilateral discharge.(4)The law of material flow in the silo was studied,and the same model of deep silo bilateral unloading was established by using the PFC3 D particle flow program.The simulation model was used to analyze the flow pattern of the simulated flow and experimental.The results show that the simulated flow pattern agrees well with the experimental flow.Which has a high diameter ratio of 1.1 silo,the discharge process occurred in the tubular flow,the warehouse there are obvious static and flow area,Then the flow area and the static area cross section are not intersected with the wall;In the silo with high diameter ratio of 2.2,during the discharge process,the mixing flow occurs,and the area was mainly distributed at the depth of about 0.3m-0.5m,which leads to the overall flow was occurred in the upper part of the silo and the tubular flow was occurred in the lower part.