OPTIMIZE AND ANALYSIS COMPRESSOR WHEEL OF TURBO CHARGER

Blade angle effect on flow field of the compressor wheel. Blade angle of compressor wheel will be analyses computationally by CFD. How the different blade angle of compressor wheel causes the effect on flow field along the blade passage and leads to variation of pressure and efficiency of the wheel. Blade angle studies are conducted to understand the flow behavior in order to minimize the effects of blade angle. Through this paper an attempt is being made to address the following:


Volumetric Efficiency
Standard numbers for peak Volumetric Efficiency (VE) in range 95% -99% for modern (four -valve) heads, to 88% -95%, for (tow-valve) designs. If have a torque curve for the engine, use this to estimate Volumetric Efficiency (VE) at difference engine speeds. On a well-tuned engine, the Volumetric Efficiency (VE) will peak at the torque maximum, and this number can be using to measurement the Volumetric Efficiency (VE) at another engine speeds. A (four-valve) engine will typically have higher Volumetric Efficiency over more of its rev range than a (2-valve) engine.

Intake Manifold Temperature
The Compressor with high efficiency give low manifold temperatures. Manifold temperature of intercooled set up typically 37.7 -54.4 0C while non-intercooled values can reach from 79.4 -148.8 0C.

Brake Specific Fuel Consumption (BSFC)
Brake Specific Fuel Consumption is described the fuel flow rate required to generate horsepower. General values of Brake Specific Fuel Consumption for turbocharger engines range between (0.50 to 0.60) Brake Specific Fuel Consumption (BSFC) = (Fuel flow rate in Newton per hour) / (BHP in KW).

N/KW-hr in SI units.
Lower BSFC means that the engine requires less fuel to generate a given horsepower. Race fuels and aggressive tuning are required to reach the low end of the BSFC range described above. For the equations below, divide BSFC by 60 to convert the hours to the minutes. To plot the point of compressor operating, first calculate airflow:

SOLUTION METHODOLOGY
This section deals with the model and mesh of the Turbocharger wheels using PRO-E and ANSYS-CFX. In ANSYS -CFX type of mesh generation and boundary conditions are same for the wheels of a turbocharger [3]. Design and Analysis of A Turbocharger Compressor Wheel. The design of the compressor wheel is done using PRO-E with following: The above mentioned geometrical specification is same for 650,450 and 350 inlet blade angles of a compressor wheel. The analysis is done for each of above specified inlet blade angle and is as follows.
Case -I Inlet Blade Angle, Β1 = 65 0 Modeling: Designing is done with the help of a PRO-E. Compressor impeller (wheel) with above geometrical specifications with 2mm thickness throughout the blade ( Figure 2).

Mesh Generation
These meshes are used in the ANSYS CFX to solve complex blade passage problems. Fine tetrahedral Meshing done, and mesh information is shown in Table 1 and mesh generation along with section view in Figure below:

Boundary Conditions
After creating the mesh in ANSYS, the mesh is analyzed in the ANSYS CFX-Pre for applying boundary conditions. And boundary conditions are same for blade inlet angle 65 0 ,45 0 and 35 0 of a compressor wheel of a turbocharger. Boundary conditions ( Figure 3) specify the flow and thermal variables on the boundaries of the physical model. And applied boundary conditions shown in Table 2 and Table 3 and is same for 65 0 ,45 0 and 35 0 inlet blade angles of a compressor wheel. Boundary conditions are considered in CFX-Pre. The working fluid is taken as air at 250C with reference pressure at 1 atm. The fluid domain is considered as stationary. ANSYS-CFX software is used for obtaining the solution and standard kturbulence model with turbulence intensity of 5% is considered. Inlet boundary conditions: inlet boundary condition was set at subsonic flow with total uniform pressure of 1atm. The turbulence intensity of 5% is considered. Outlet boundary conditions: outlet boundary condition was set at subsonic flow with relative pressure 0 kpa. Solid boundaries: The solid or wall, boundaries included the impeller. A smooth surface and no heat transfer (adiabatic flow) were assumed for all the wall boundaries.

Modeling
Designing is done with the help of a PRO-E. Compressor impeller (wheel) with above geometrical specifications with 2mm thickness throughout the blade ( Figure 5).

Mesh Generation
These meshes are used in the ANSYS CFX to solve complex blade passage Fine tetrahedral Meshing done, and mesh information is shown in Table 4 and mesh generation along with section view.

Boundary Conditions
After creating the mesh in ANSYS, the mesh is analyzed in the ANSYS CFX-Pre for applying boundary conditions (Figure 7). The boundary condition is similar to inlet blade angle, β1 = 650 of a compressor wheel.

Modeling
Designing is done with the help of a PRO-E. Compressor impeller (wheel) with above geometrical specifications with 2mm thickness throughout the blade (Figure 8).

Mesh Generation
These meshes are used in the ANSYS CFX to solve complex blade passage problems. Fine tetrahedral Meshing done, and mesh information is shown in Table 5 and mesh generation along with section view (Figure 9).

Boundary Conditions
After creating the mesh in ANSYS, the mesh is analyzed in the ANSYS CFX-Pre for applying boundary conditions (Figure 10). The boundary condition

Domain Nodes Elements
Fluid 79725 403682 Impellor 32661 145299 All Domains 112386 548981 is similar to inlet blade angle, β1 = 650 of a compressor wheel.  Mass flow at outlet, Wa = 0.982715 [kg /s] is obtained from cfd software, and by calculation pressure ratio, πc = 2.33 is obtained and marking these values on a compressor map and found η=80% for a 8.1L engine as shown in figure 13.GT6041 compressor map.

CONCLUSION
It is observed that inlet blade angle, β1 = 650 are more efficient than other inlet blade angle, β1 = 350 and 450 this can be observed from pressure contour and this wheel is best suited for 8.1L engine having 7200 rpm and it gives η = 80%.
From velocity streamline it is observed that flow field in the blade passage is quit smooth in inlet blade angle, β1 = 650 than other blade angles.
i.) In inlet blade angle, β1 = 350 it is observed that flow field in the blade passage is also smooth but if we observe the pressure Vs velocity streamline graph it is not building more pressure than β1 = 650, hence it is not so efficient.
ii.) In inlet blade angle, β1 = 450 it is observed that some fluid in blade passage is mixing with beside flow field of a blade passage it can be observe in velocity streamline and due to this pressure Vs velocity streamline graph is more fluctuating.