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Sunny_sXe [5.5K]

3 years ago

5

Air enters an adiabatic turbine at 900 K and 1000 kPa. The air exits at 400 K and 100 kPa with a velocity of 30 m/s. Kinetic and

potential energy changes are negligible. If the power delivered by the turbine is 1000 kW.
Required:
a. Find the mass flow rate.
b. Find the diameter of the duct at the exit.

1 answer:

Ivanshal [37]3 years ago

3 0

hooooooooooooooooooooooooooooooooooooooooooooooooooooooe

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Heats of Reaction and Hess's Law experiment tells you to look up three values. Write down these values. Be sure to clearly indic

Anna [14]

Answer:

Enthalpy of reaction (kJoules/mole)

Heat of formation of products (kJoules/mole)

Heat of reaction of reactants (kJoules/mole)

Explanation:

The general expression for calculating the overall enthalpy of reaction is given as following:

ΔH = ∑ΔH[producst] - ∑Δ[reactants]

Thus, the heat of reaction is given as the difference between the formation of the products and the formation of the reactants. The units are expressed as kJ/mol of reactants or products.

Thus, the three values are fundamental in the determination of the overall energy of the reaction from Hess' Law.

8 0

3 years ago

An industrial plant consists of several 60 Hz single-phase motors with low power factor. The plant absorbs 600 kW with a power f

Gelneren [198K]

Answer:

(a) $Q=332$ $kvar$ and $C=5.66$ $uF$

(b) $pf=0.90$ lagging

Explanation:

Given Data:

$P=600kW$

$V=12.47kV$

$f=60Hz$

$pf_{old} =0.75$

$pf_{new} =0.95$

(a) Find the required kVAR rating of a capacitor

$\alpha _{old}=cos^{-1}(0.75) =41.41$ °

$\alpha _{new}=cos^{-1}(0.95) =18.19$ °

The required compensation reactive power can be found by

$Q=P(tan(\alpha_{old}) - tan(\alpha_{new}))$

$Q=600(tan(41.41) - tan(18.19))$

$Q=332$ $kvar$

The corresponding capacitor value can be found by

$C=Q/2\pi fV^{2}$

$C=332/2*\pi *60*12.47^{2}$

$C=5.66$ $uF$

(b) calculate the resultant supply power factor

First convert the hp into kW

$P_{mech} =250*746=186.5$ $kW$

Find the electrical power (real power) of the motor

$P_{elec} =P_{mech}/n$

where $n$ is the efficiency of the motor

$P_{elec} =186.5/0.80=233.125$ $kW$

The current in the motor is

$I_{m} =(P/\*V*pf)$

The pf of motor is 0.85 Leading

Note that represents the angle in complex notation (polar form)

$I_{m} =(233.125/12.47*0.85)$

$I_{m}=18.694+11.586$ $j$ $A$

Now find the Load current

pf of load is 0.75 lagging (notice the minus sign)

$I_{load} =(600/12.47*0.75)$

$I_{load} =48.115-42.433$ $j$ $A$

Now the supply current is the current flowing in the load plus the current flowing in the motor

$I_{supply} =I_{m} + I_{load}$

$I_{supply}= (18.694+11.586)+(48.115-42.433)$

$I_{supply} =66.809-30.847j$ $A$

or in polar form

$I_{supply} =73.58$ °

Which means that the supply current lags the supply voltage by 24.78

therefore, the supply power factor is

$pf=cos(24.78)=0.90$ lagging

Which makes sense because original power factor was 0.75 then we installed synchronous motor which resulted in improved power factor of 0.90

8 0

3 years ago

There are four distinct events that occur in the Carnot cycle. Name the events and describe each one.

OLEGan [10]

Answer and Explanation:

There four events or stages of reversible nature in a Carnot cycle are:

1. Isothermal expansion of gas

2. Adiabatic expansion

3. Isothermal compression of gas

4.Adiabatic compression of gas

All these 4 processes are reversible processes.

1. A reversible Isothermal expansion of gas takes place in Carnot cycle where an ideal gas absorbs or intake certain quantity of heat from a heat reservoir or source at an elevated temperature which results in the expansion of gas and work is done on the surroundings.

2. A reversible expansion of gas adiabatically takes place in Carnot cycle in an environment with thermal insulation where the gas expand and work is done on the surrounding which results in the lowering of the temperature of the system.

3. A reversible compression of gas isothermally takes place such that the work is done on the system by the surrounding resulting in heat loss.

4. A reversible compression of gas adiabatically, takes place in an environment with thermal insulation and the work is done continuously on the system by the surroundings resulting in the rise in temperature.

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The average age of engineering students at graduation is a little over 23 years. This means that the working career of most engi

RideAnS [48]

Answer:

$916

Explanation:

To solve this, we use the formula

FV = P/i * [(1+i)^n - 1], where

FV = future value of the all the money invested, $5 million

n = time span, = 500 months

P = payment per month

I = interest rate, 9% by 12 months, = 0.0075

Considering that we have been given all in our question, then we substitute directly and solve. So we have,

5000000 = P/0.0075 * [(1+0.0075)^500 -1]

5000000 * 0.0075 = P * [1.0075^500 - 1]

37500 = P * [41.93 - 1]

37500 = P * 40.93

P = 37500/40.93

P = $916.20

Therefore, the engineer needs to save $916 in a month which is the accrued

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3 years ago

Using benefit-cost ratio analysis, determine which one of the three mutually exclusive alternatives should be selected. Each alt

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Hamborger hamborger hamborger hamborger

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