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Strike441 [17]
2 years ago
15

H2O enters a conical nozzle, operates at a steady state, at 2 MPa, 300 oC, with the inlet velocity 30 m/s and the mass flow rate

is 50 kg/s. The exit pressure and temperature are 0.6 MPa and 160 oC, respectively. Please determine the inlet radius as well as the exit flow velocity. Hint: While the effect of heat transfer can be neglected, the change of the kinetic energy should be accounted for.
Engineering
1 answer:
Colt1911 [192]2 years ago
7 0

Answer:

The flow velocity at outlet is approximately 37.823 meters per second.

The inlet radius of the nozzle is approximately 0.258 meters.

Explanation:

A conical nozzle is a steady state device used to increase the velocity of a fluid at the expense of pressure. By First Law of Thermodynamics, we have the energy balance of the nozzle:

Energy Balance

\dot m \cdot \left[\left(h_{in}+\frac{v_{in}^{2}}{2} \right)-\left(h_{out}+\frac{v_{out}^{2}}{2} \right)\right]= 0 (1)

Where:

\dot m - Mass flow, in kilograms per second.

h_{in}, h_{out} - Specific enthalpies at inlet and outlet, in kilojoules per second.

v_{in}, v_{out} - Flow speed at inlet and outlet, in meters per second.

It is recommended to use water in the form of superheated steam to avoid the appearing of corrosion issues on the nozzle. From Property Charts of water we find the missing specific enthalpies:

Inlet (Superheated steam)

p = 2000\,kPa

T = 300\,^{\circ}C

h_{in} = 3024.2\,\frac{kJ}{kg}

\nu_{in} = 0.12551\,\frac{m^{3}}{kg}

Where \nu_{in} is the specific volume of water at inlet, in cubic meters per kilogram.  

Outlet (Superheated steam)

p = 600\,kPa

T = 160\,^{\circ}C

h_{out} = 2758.9\,\frac{kJ}{kg}

If we know that \dot m = 50\,\frac{kJ}{kg}, h_{in} = 3024.2\,\frac{kJ}{kg}, h_{out} = 2758.9\,\frac{kJ}{kg} and v_{in} = 30\,\frac{m}{s}, then the flow speed at outlet is:

35765-25\cdot v_{out}^{2} = 0 (2)

v_{out} \approx 37.823\,\frac{m}{s}

The flow velocity at outlet is approximately 37.823 meters per second.

The mass flow is related to the inlet radius (r_{in}), in meters, by this expression:

\dot m = \frac{\pi \cdot v_{in}\cdot r_{in}^{2} }{\nu_{in}} (3)

If we know that \dot m = 50\,\frac{kJ}{kg}, v_{in} = 30\,\frac{m}{s} and \nu_{in} = 0.12551\,\frac{m^{3}}{kg}, then the inlet radius is:

r_{in} = \sqrt{\frac{\dot m\cdot \nu_{in}}{\pi\cdot v_{in}}}

r_{in}\approx 0.258\,m

The inlet radius of the nozzle is approximately 0.258 meters.  

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Answer:

33.429 N-m

Explanation:

Given :

Inclination angle of two shaft, α = 20°

Speed of shaft A, N_{A} = 1000 rpm

Mass of flywheel, m = 30 kg

Radius of Gyration, k =100 mm

                                   = 0.1 m

Now we know that for maximum velocity,

\frac{N_{B}}{N_{A}} = \frac{cos\alpha }{1 - sin^{2}\alpha }

\frac{N_{B}}{1000} = \frac{cos20}{1 - sin^{2}20 }

N_{B} = 1064.1 rpm

Now we know

Mass of flywheel, m = 30 kg

Radius of Gyration, k =100 mm

                                   = 0.1 m

Therefore moment of inertia of flywheel, I = m.k^{2}

                                                                      =30 X 0.1^{2}

                                                                     = 0.3 kg-m^{2}

Now torque on the output shaft

T₂ = I x ω

    = 0.3 X 1064.2 rpm

    = 0.3\times \frac{2\pi \times 1064.1}{60}

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Torque on the Shaft B is 33.429 N-m

4 0
3 years ago
ABS system is necessary?
Monica [59]

Explanation:

I think it helps you

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2 years ago
The coefficient of static friction for both wedge surfaces is μw=0.4 and that between the 27-kg concrete block and the β=20° inc
balandron [24]

Assuming  the wedge has an angle of 5°.The minimum value of the force P that is required to begin moving the block up the incline is: 322.84 N.

<h3>Minimum value of force P</h3>

First step

Using this formula to find the weight of the block

W=mg

W=27×9.81

W=264.87 N

Second step

Angles of friction ∅A and ∅B

∅A=tan^-1(μA)

∅A=tan^-1(0.70)

∅A=34.99°

∅B=tan^-1(μB)

∅B=tan^-1(0.40)

∅B=21.80°

Third step

Equate the sum of forces in m-direction to 0 in order to find the reaction force at B.

∑fm=0

W sin (∅A+20°)  + RB cos (∅B+∅A)=0

264.87 sin(34.99°+20°) + RB cos (21.80°+34.99°)=0

216.94+0.5477Rb=0

RB=216.94/0.5477

RB=396.09 N

Fourth step

Equate the sum of forces in x-direction to 0 in order to find force Rc.

∑fx=0

RB cos (∅B) - RC cos (∅B+ 5°)=0

396.09 cos(21.80°) - RC cos (21.80°+5°)=0

RC=396.09 cos(21.80°)/cos(26.80°)

RC=412.02 N

Last step

Equate the sum of forces in y-direction to 0 in order to find force P required to move the block up the incline.

∑fy=0

RB sin (∅B) + RC sin (∅B)-P=0

P=Rb sin (∅B) + RC sin (5°+∅B)

P=396.09 sin(21.80°) +412.02sin (5°+21.80°)

P=322.84 N

Inconclusion the minimum value of the force P that is required to begin moving the block up the incline is: 322.84 N.

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2 years ago
Convert 250 lb·ft to N.m. Express your answer using three significant figures.
vfiekz [6]

Answer:

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Explanation:

We have to convert 250 lb-ft to N-m

We know that 1 lb = 4.45 N

So foe converting from lb to N we have to multiply with 4.45

So 250 lb = 250×4.45 =125 N

And we know that 1 feet = 0.3048 meter

Now we have to convert 250 lb-ft to N-m

So 250lb-ft=250\times 4.45N\times 0.348M=338.95N-m

So 250 lb-ft = 338.95 N-m

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3 years ago
Five hundred gallons of 89-octane gasoline is obtained by mixing 87-octane gasoline with 92-octane gasoline. (a) Write a system
miskamm [114]

Explanation:

a) The total volume equals the sum of the volumes.

500 = x + y

The total octane amount equals the sum of the octane amounts.

89(500) = 87x + 92y

44500 = 87x + 92y

b) desmos.com/calculator/ekegkzllqx

As x increases, y decreases.

c) Use substitution or elimination to solve the system of equations.

44500 = 87x + 92(500−x)

44500 = 87x + 46000 − 92x

5x = 1500

x = 300

y = 200

The required volumes are 300 gallons of 87 gasoline and 200 gallons of 92 gasoline.

6 0
3 years ago
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