Evaluation of Aerodynamic Coefficients of High Temperature Gas Turbine Cascade of Cooled Blade

The aerodynamic force coefficients of five linear cascade of existing film cooling turbine blades are evaluated numerically. The blade is geometrically identical to the first rotor blades of the high pressure (HP) turbine of the F-100-PW-220 military turbofan. Cascade turbine blade test rig has been designed, constructed, and calibrated to introduce experimental work for the same flow conditions of the numerical solution to validate correctness of the numerical results. The numerical simulation shows acceptable agreement with experimental. Also it was found experimentally that both lift and drag coefficients are increased slightly with add of film cooling. The local Mach number distributions outside the boundary layer on both blade sides of the cascade blade are evaluated numerically and compared with the results of well known CFD code (Fine/Turbo) for existing gas turbine rotor stage of identical blade. The computational results obtained for both cases show that the Mach number distributions trend along both blade sides for rotor stage and cascade are approximately the same, and the values of Mach number of rotor stage are higher than that for the corresponded cascade. Also it was found that the Mach number distributions on both blade sides are reduced in values by the addition of air cooling, and the local Mach numbers for the cascade case is reduced in values among the rotor stage for the two cases with and without film cooling on both blade sides

Experimental Investigation of Jet Impingement Cooling On Ribbed Target Surface

Experimental investigation of jets impacting at right angleon a flat surfaceis introduced in the present study. Round jet holes of inline arrays arrangements with diameter (5mm) and jet to jet spacing of 4 jet hole diameter are considered. Jet Reynolds numbers of 4000 to 16000 and jet height to diameter ratio (space between the jet plate and target plate) of 2.0 is maintained. The heat transfer model consists of amultiple jet holes, ribbed target plate having back side resistive film. Threetarget models have been considered; model (1) is a clean surface target acting as the baseline case, the model (2) the target surface consists of lateral rib rows and model (3) the target surface consists grids rib arrangement. The ribs height for models (2 and 3) is 0.86 of jet diameter of the triangle shape. The average wall cooling effectiveness and heat transfer coefficients and consequently the Nusselt numbers for each model are estimated. Numerical computations of jets flow field are made.Theresults show that model (3) enhanced both heat transfer coefficients in the target plat inner surface and wall cooling effectiveness in the target plat outer surface greatly,the maximum increments in heat transfer coefficient and wall coolingeffectiveness are 14.5% and 4.5% respectively

AXIAL FAN BEARING SYSTEM VIBRATION ANALYSIS

Rotating fan shaft system was investigated experimentally and theoretically to study its dynamic performance. The type of oil used for the bearing was taken in consideration during the experimental program .Three types of oil were used, SAE 40, SAE 50 and degraded oil. During the experiments, the fan blades stagger angle was changed through angles (20˚, 30˚, 40˚, and 50˚). The shaft rotational speed also changed in the range of (0-3000 rpm). All these parameters have investigated for two cases (balanced and unbalanced fan). The performance parameters of the fan were found experimentally by measuring the fan, volume flow rate, Reynolds and Strouhal numbers, efficiency and pressure head. Analytical part was also represented to prepare the prediction of fan system dynamic performance. The aerodynamic forces and moments of each blade were also predicted to obtain the rotor dynamic future. Experimentally and theoretically the critical fan speed was obtained in the x and y direction for different lubricant oil viscosities and shaft rotational velocities for balanced and unbalanced fan. Analysis of the vibrational response gave important information about the dynamic performance of fan rotating system. Acceptable agreement was found between analytical and experimental results

Effect of Surface Roughness Height on the Aerodynamics Performance of Axial Compressor Cascade Blades

The performance of fluid handling mechanical parts such as compressor blades are usually significantly affected by the surface roughness, because they often operate in condition of peak output that is close to this flow condition. The influence of surface height roughness of compressor blades has been investigated experimentally under the effect of cascade stagger angle. The experimental results done by using the direct measuring technique showed that the aerodynamic coefficients of compressor cascade blades influences by presences of surface roughness and stagger angle. The lift coefficient, pitching moment coefficient and cascade blade efficiency were reduced, while the drag coefficient is increased, with the increase of height roughness. The height of roughness does eliminate the operating condition of the cascade blades, which reduce the value of the stall angle

One Parameter Composite Semigroups of Linear Bounded Operators in Strong Operator Topology of Schatten Class Cp

For semigroups of linear bounded operators on Hilbert spaces, the problem of being in Cp , 0 Keyword