No abstract

Within the range of finite land resources, in order to improve the power generation efficiency of wind farms and reduce the impact of wake effects on the output power of fans, the rationality of wind farm fan layout is very important. The wake velocity and output power of two 2.5MW experimental fans in series 5D spacing are obtained by means of Doppler measured anemometer of windcube2. Based on CFX numerical simulation method, the simulation of the wake field is carried out by ANSYS software. The results showed that the fan spacing of 5D, the simulation and experimental results were basically the same. As the axial distance increased, the axial velocity first decreased and then increased, gradually recovered the incoming wind speed. The radial velocity and the tangential velocity amplitude and frequency fluctuation of different sections at the same angle were gradually reduced. The amplitude and frequency fluctuation of the tangential velocity were the largest at 3D, and were the minimum at 8D. The amplitude and frequency fluctuation of the radial velocity were the largest at 5D, and were the minimum at 3D. The velocity at the center of the bub gradually increased, and the velocity variation was the most obvious at 3D. The simulation speed first appeared an upward trend. Due to the superposition of the upstream fan wake, the output power of the downstream fan was greatly affected. Therefore, in the actual planning of the wind farm, the downstream fan should not be completely arranged in the wake field of the upstream fan.

This paper presents welding torch pose model and interpolation algorithm of trajectory control of saddle-shaped weld formed by intersection of two pipes; the working principle, interpolation algorithm, welding experiment, and simulation result of the automatic welding system of the saddle-shaped weld are described. A variable angle interpolation method is used to control the trajectory and pose of the welding torch, which guarantees the constant linear terminal velocity. The mathematical model of the trajectory and pose of welding torch are established. Simulation and experiment have been carried out to verify the effectiveness of the proposed algorithm and mathematical model. The results demonstrate that the interpolation algorithm is well within the interpolation requirements of the saddle-shaped weld and ideal feed rate stability.

Take one subway station of Chongqing rail transit as background, 3D FEM models of sequential excavating to large-section and ultra-deep shafts under complicated environment were set up, and influence of shaft construction to the stability of shaft wall rock, slab-pile walls, high-voltage tower foundation and intersection of shafts and air flues was analyzed. The analysis result showed: wall rock displacement near the contour line of shaft and air flue changed significantly and the maximum displacement was 10.84 mm; vertical displacement caused by shaft and air flue excavating affected ground surface and the maximum ground surface settlement was 20 mm; shaft excavating brought large stress to shaft walls and the maximum vertical stress was 2.94 MPa; plastic zone of wall rock mainly distributed in the junction of shaft and air flue, outward excavation contour line for 6-10 m, and the distribution range was large. The maximum principal stress of shaft and air flue during initial support at the junction of air flue vault and curve walls was large, and the maximum stress was 6.09 MPa; the maximum and minimum principal stress of slab-pile retaining walls before shaft and air flue excavating was -1.60 MPa and 0.32 MPa, then increased to -1.78 MPa and 0.63 MPa respectively after excavating, additionally, shear failure would not happen; the maximum displacements from X-scale, Y-scale and Z-scale of tower's foundation were 0.32 mm, 0.86 mm and 1.20 mm respectively. Furthermore, the difference of inhomogeneous deformation was small, and shaft construction had no effect to high-voltage towers.