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3 years ago

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A steam pipe for a 300-m-tall building receives superheated steam at 200 kPa at ground level. At the top floor the pressure is 1

25 kPa, and the heat loss in the pipe is 110 kJ/kg. What should the inlet temperature be so that no water will condense inside the pipe?

1 answer:

ohaa [14]3 years ago

8 0

Answer:

inlet temperature is $170^{\circ}C$ be so that no water will condense inside the pipe

Explanation:

Assumptions,

No change in the kinetic energy
Steady state

single inlet and exit flow

The energy equation is given by

$q+h_i=h_e+gZ_e$

No condensation means

$h_{e}=h_{g} \text { at } 125k P a=2685.4 \mathrm{kJ} / \mathrm{Kg}$

$h_i=h_e+gZ_e-q$

Substituting the values,

= $2685.4+\frac{9.807 \times 300}{1000} -(-110)$

= $2685.4+\frac{2942.1}{1000} -(-110)$

= $2685.4+ 2.9421 -(-110)$

= $2685.4+ 2.9421 + 110$

=2798.34 kJ/kg

At 200 kPa T $\sim$ 170

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Q= mcΔT

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You have to convert Celsius into kelvin in order to use this formula I believe

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Answer:

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Explanation:

Given that,

Activity $R_{0}=10\ mCi$

Time $t_{1}=4\ hours$

Activity R= 8 mCi

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Using formula of activity

$R=R_{0}e^{-\lambda t}$

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$\lambda=1.55\times10^{-5}\ s^{-1}$

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Using formula of half life

$T_{\dfrac{1}{2}}=\dfrac{ln(2)}{\lambda}$

Put the value into the formula

$T_{\dfrac{1}{2}}=\dfrac{ln(2)}{1.55\times10^{-5}}$

$T_{\dfrac{1}{2}}=44.719\times10^{3}\ s$

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Using formula of $N_{0}$

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Put the value into the formula

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Put the value intyo the formula

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Answer:

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A non-conservative force instead does not show this properties, as the work done by it depends on the path taken, and therefore it is not possible to define a potential energy function. An example of non-conservative force is friction.

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