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ohaa [14]
3 years ago
10

The conditions at the beginning of compression in an Otto engine operating on hot-air standard with k=1.35 and 101.325 kPa, 0.05

m3 and 32C. The clearance is 8% and 15kJ are added per cycle. Determine the mean effective pressure.
Engineering
1 answer:
Katyanochek1 [597]3 years ago
6 0

Answer:

P_m=181.42 KPa

Explanation:

P_1=101.325 KPa,V_1=0.05m^3,T_1=32C,K=1.35

Clearance is 8%.

Heat added=15 KJ

We know that compression ratio r=1+\dfrac{1}{C}

r=1+\dfrac{1}{0.08}  

r=13.5

r=\dfrac{V_1}{V_2}

13.5=\dfrac{0.05}{V_2}

V_2=3.7\times 10^{-3}

We know that efficiency of otto cycle

\eta =1-\dfrac{1}{r^{k-1}}

\eta =1-\dfrac{1}{13.5^{1.35-1}}

\eta =0.56

\eta =\dfrac{W}{Q}

W is the work out put and Q is the heat addition.

0.56 =\dfrac{W}{15}

W=8.4 KJ

We know that Work =Mean effective pressure x swept volume.

Here swept volume V_s=V_1-V_2

V_s=0.05-3.7\times 10^{-3}

V_s=0.0463 m^3

Noe by putting the values

Work =Mean effective pressure x swept volume.

8.4=P_m\times 0.0463

P_m=181.42 KPa

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so here mass flow rate is

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mass flow rate m = 0.10139 kg/s

so heat required is

H = h × m  

here h is heat required and m is mass flow rate

H = 2680.36  × 0.10139

H =  271.75 kJ/s = 271.75 kW

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net boiler heat = \frac{271.75}{0.90}

net boiler heat = 301.94 kW

5 0
3 years ago
Show the ERD with relational notation with crowfoot. Your ERD must show PK, FKs, min and max cardinality, and correct line types
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Step-by-step explanation:

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Answer:

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T₁=450 K

P₁=350 KPa

C₁=3 m/s

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For ideal gas

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\rho_1=\dfrac{P_1}{RT_1}

\rho_1=\dfrac{350}{0.287\times 450}

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4 0
2 years ago
If a dielectric material, such as teflon®, is placed between the plates of a parallel-plate capacitor without altering the struc
erastovalidia [21]

The capacitance is affected is that the capacitance increases because of the insertion of Teflon.

<h3>What is capacitance?</h3>

A `is known to be a form of a device that is said to be used to save some amount of charges in any electrical circuit.

Note that the capacitor functions on the principle that the capacitance of a conductor is said to increases if an earthed conductor is  taken close to it.

Hence, The capacitance is affected is that the capacitance increases because of the insertion of Teflon.

See full question below

A dielectric material, such as Teflon®, is placed between the plates of a parallel-plate capacitor without altering the structure of the capacitor. The charge on the capacitor is held fixed. How is the electric field between the plates of the capacitor affected?

The electric field is not altered, because the structure remains unchanged.

The electric field becomes zero after the insertion of the Teflon®.

The electric field decreases because of the insertion of the Teflon®.

The electric field becomes infinite because of the insertion of the Teflon®.

The electric field increases because of the insertion of the Teflon®.

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