The flow within turbomachines is intrinsically complex and involves boundary layer transition, separation and vortices such as the tip leakage vortex and wakes. In a low-pressure turbine, as the Reynolds number can be small, the flow over the suction side is likely to separate leading to the formation of a laminar (or transitional) separation bubble. This flow mechanism can be predicted using Large-Eddy Simulation. However the computation is still very expensive in a design framework. Thus, Reynolds-Averaged Navier-Stokes (RANS) method is used in the present investigation to simulate the flow over the low-pressure turbine airfoil T106C. The laminar-turbulent transition is modeled with the γ-Rθt~ model of Menter and Langtry. Following the work of Minot et al. in which the CFD setup was deeply investigated, the present study aims at evaluating the sensitivity to uncertainties relative to experimental values (freestream turbulence, Reynolds number, incidence flow angle and exit isentropic Mach number) and at improving this model regarding the calibration of several functions using optimization process. The uncertainty study highlights the parameters which mainly influence the isentropic Mach number and loss distributions. The new calibration of the Menter-Langtry model improves significantly the flow prediction over the suction side, except for the open bubble configuration.
The plot seeders have a variety of distribution systems makes it possible to distribute the seed for a plot over multiple rows and many options allows you to customize the machine for many different applications. So when used a plot seeder to suitable for cultivation of wheat seeds must adjustment transmission mechanism and a feed cartridges diameter, as well as seeding shaft and distributor cone rotates. This study carried out to improve the performance of plot seeder and minimize the total damage during wheat seed production processes. The treatments under this study were at four diameters of feed cartridges (10, 15, 20 and 25 mm Ø), two kinds of distributor plat (distributor plat with and without partition)and three groups of sowing transmission. The variation coefficient of seeds and seeds damage were measured. The seeds damage generally increased with the decrease of feed cartridge from 15.6% at feed cartridge diameter (10 mm Ø) to 2.4% at feed cartridge diameter (25 mm Ø). Also seeds damage increased with distributor plat with partition. That was 15.6% with distributor plat with partition and 14.6% without partition. The variation coefficient of seeds decreases at diameter of feed cartridge (20 mm Ø) with distributor plat without partition and the first group of sowing transmission.
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