Characteristics of wind turbine wake and particle transport in aeolian sand environment

For the wind turbine wake field in the aeolian sand environment, the multiphase flow model is used to simulate the wind sand inflow and the wake of the wind turbine is simulated and calculated in combination with the actuation line model based on the OpenFOAM-v2006. The effects of clean air inflow and wind sand inflow on the wind turbine wake field are compared, including speed loss and wake structure. Equally the particle transport in the wake of wind turbine is analyzed. The results show that the velocity of wind turbine wake recovers faster in the aeolian sand environment, the overall spatial structure is sinking, and the particles will settle in advance and distribute in strips

Cutting Force Prediction Models by FEA and RSM When Machining X56 Steel with Single Diamond Grit

In the field of underwater emergency maintenance, submarine pipeline cutting is generally performed by a diamond wire saw. The process, in essence, involves diamond grits distributed on the surface of the beads cutting X56 pipeline steel bit by bit at high speed. To find the effect of the different parameters (cutting speed, coefficient of friction and depth of cut) on cutting force, the finite element (FEA) method and response surface method (RSM) were adopted to obtain cutting force prediction models. The former was based on 64 simulations; the latter was designed according to DoE (Design of Experiments). Confirmation experiments were executed to validate the regression models. The results indicate that most of the prediction errors were within 10%, which were acceptable in engineering. Based on variance analyses of the RSM models, it could be concluded that the depth of the cut played the most important role in determining the cutting force and coefficient the of friction was less influential. Despite making little direct contribution to the cutting force, the cutting speed is not supposed to be high for reducing the coefficient of friction. The cutting force models are instructive in manufacturing the diamond beads by determining the protrusion height of the diamond grits and the future planning of the cutting parameters