Contra-Rotating Compressor

He explained this phenomenon with

so did Newton.

Everybody noticed that if they push something that thing would be in

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the laws of motion

Newton realized that rate of change of momentum and force are interrelated and made the famous formula that expresses this relationship mathematically:

t

Force.

o

m

u

n

m

t

e

m

though this theory seemed perfect to explain the physical working of axial compressor

mv

1

mv

2

What all qualities do we want in future aircraft engine?

Fuel Consumption

Level

Less size and weight

Engine %

and here

comes our model

so these are the miraculous rules of our universe

We used the same phenomenon with some modifications:

We removed stators

Benefits

- Reduction in weight

-More pressurization in

reduced length

W_r= U*(C_w2 - C_w1)

- Possibility of contra-

rotating turbine

-Compact but powerful

power plants

2nd

1-Contra-rotating compressor has undoubtedly

several advantages than traditional

compressor

Completely fulfills the requirements of the future engine

Designing of Contra-Rotating

Compressor

1st

Fabrication

-Compressor is being fabricated in 7 parts made of acrylic plastics

-Deep groove roller bearings to house outer rotating casing inside a non-rotating backbone shell

-Association for designing a contra-rotating gearbox-Intake and exit were incorporated-Connector Design

Detailed analysis of each mechanical part

Objectives:-

-Connect the cast epoxy compressor rotors with the metal drive unit-Avoid the obstruction of flow by the gearbox

How to connect shafts of

gearbox to shafts of

compressor?

Coupling Design

Gear Box Efficiency

98%

-Customized gearbox in collaboration with IIT Bombay

-Output shafts are contra-rotating based on the compressor directions

-Motor + VFD to achieve the desired output rpm

Gear Box and Motor + VFD

5 HP

2835

80%

0.9

19.7 Kg

Motor Specifications

Motor Power

Rated RPM

Efficiency

Power Factor

Weight

How to get this contra-rotation?

Gear Box

Design Process

Spline Teeth Coupling

Key Way Coupling

Gearbox Side

14.5 cm

7.25 cm

2.90 cm

29.0 cm

4:1

Value

Major Axis

Minor Axis

Radius

Inlet Diameter

Area Ratio

Parameters

Coupling Design

Exit

Coil Spring Coupling

Spline Teeth Coupling

Compressor Side

Mechanical

Design

Aerodynamic

Design

Outer Shaft

Inner Shaft

Inner Connector

Outer Connector

-2 contra-rotating shafts

-1st and 3rd stage rotors are integrated on an inner hollow shaft

-2nd and 4th are integrated to a outer casing

-Outer casing is housed inside a stationary backbone shell

CFD Analysis

4-stage compressor with Intake

-Elliptic bell mouth profile (CFD Optimized)

-CD values > 0.95

-Works well up to M < 0.65

ASME Bell Mouth Intake

Intake

Beneficial Conclusions

Mechanical Design

Blade Design

• Camber angle
• Blade inlet and outlet angle
• stagger angle

Blade design was optimized through

CFD simulation

DO YOU NOW SEE THE LIGHT?

25 mm(Length) X 11 mm(Diameter)

25mm(Length) X 6.5mm(Thick) X with

19mm inner diameter

200 mm(Length) X 2.5 mm(thickness)

30 mm(Length) X 1.5 mm(Diameter

of Coil)

1.5mm(depth) X 25mm(length)

X 9 (Number of Teeth)

3 mm (depth)

Parts Specifications:-

Initial Blade Design to start the Design iteration....

Gearbox

Connector

Inner Shaft Dimension

Outer Shaft Dimension

Inner Connector Dimension:

Coil Spring Coupling Dimension:

Inner Coupling Dimension (G.B.side):

Outer Coupling Dimension (G.B.side):

Let's have assembly video...

The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole.

the very heavy radio stars, whose gravitational field is so strong that even light can't escape from them. that's why they are 'invisible'

Maximize the pressure ratio

?

Objective

Preliminary Blade Design

-Camber Angle

-Blade Inlet and Outlet Angle

-Stagger Angle

)

Compressor RPM, Mass Flow Rate, Geometry Configuration

-Power Requirement < 2.5 KW

-Max. Diffusion factor:

Hub < 0.6, Tip < 0.4Max.

-Deflection < 40 degrees

-Exit angle = Inlet angle

Constraints

Objective_function(

9

Stage-2

-Number of Stages

Hub 36.79 & Tip 31.27

-Stagger Angle(degrees)

Hub 25.37 & Tip 20.03

-Camber Angle(degrees)

8

Stage-3

Hub 7.00 & Tip 3.80

-Radius(cm)

-Number of Stages

Hub -8.98 & Tip 14.38

-Stagger Angle(degrees)

8

Hub 36.33 & Tip 25.19

-Camber Angle(degrees)

-Number of Stages

Hub 3.75 & Tip 6.95

Stage-1

-Radius(cm)

Hub -5.39 & Tip 14.47

-Stagger Angle(degrees)

Hub 36.95 & Tip 25.18

-Camber Angle(degrees)

9

Stage-4

Hub 3.75 & Tip 6.95

-Number of Stages

-Radius(cm)

Hub 25.25 & Tip 31.22

-Stagger Angle(degrees)

Hub 33.03 & Tip 20.22

-Camber Angle(degrees)

Hub 7.00 & Tip 3.80

-Radius(cm)

Final Blade Design

Rotor 4

Rotor 3

Rotor 2

Rotor 1

CFD Results: Wake Profiles

Tip Clearance = 1% of the mid span

Tip Clearance = 3.5% of the mid span

86.1 %

81.8 %

87.8 %

84.1 %

76 %

426

406

426

416

1510

Stage-1

Stage-2

Stage-3

Stage-4

Overall

82.8 %

79 %

83.4 %

83.5 %

74 %

400

365

374

384

1330

Stage-1

Stage-2

Stage-3

Stage-4

Overall

Isentropic

Efficiency

Pressure Rise

(in Pa)

Isentropic

Efficiency

Pressure Rise

(in Pa)

2 Cases

Tip Clearance = 3.5% of the mid span

Total Pressure Contours at 90% span

Total Pressure Contours at 10% span

CFD Results: Span Wise

-Shear stress transport model (SST)

-Convergence criteria:

Residuals < 10^-2

-Compressor Inlet

P = 1 atm

T = 300K

-Rotors

3600 rpm

-Compressor

OutletMass flow rate = 0.665 kg/s

Solver

Boundary Conditions

-2 million nodes

-H/J/C/O grids

-Max. face angle < 155

-Min face angle > 20

-Inlet Domain

-Outlet Domain

-Four Rotors

Mesh

Computational Domain

CFD Simulation