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Design and Stress Analysis of Extraterrestrial ... - The Black Vault

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; I<br />

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l7<br />

I<br />

II I' * •,,<br />

1' 1.<br />

-e Pa<br />

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P INa tip<br />

a<br />

Oi C21!<br />

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F<br />

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Fig. 3.17.' <strong>Stress</strong>es from Fig. 3.18. Determining the gas<br />

centrifugal forces in a blade ' forces acting on ýhe blade foil.<br />

.,foil <strong>of</strong> variable cross section<br />

'a- without the b<strong>and</strong> web; b -<br />

wit4 the b<strong>and</strong> iweb.<br />

U<br />

I<br />

Fx~om gas-dynamic analysis <strong>of</strong> a turbine , the folowing gas ,(steam) ,<br />

.-parametqrs are known:<br />

',-.he projections <strong>of</strong> gas velocities onto an axis coinciding with<br />

the axis <strong>of</strong> shaft rotation apd onto an axis perpendicular to it,<br />

"c.a; clu; c 2 a; C2u;<br />

circular ?vdlocdities on a given rad' s u;, gas density (steam)<br />

Pl <strong>and</strong> P 2 ; gas pressure (steam) p 1<br />

ar•d',2'<br />

<strong>The</strong> subscript "I" indicate,, quantities which characterize<br />

the state <strong>of</strong> the gas at stage ifipwt, the'subscript "2" at stage<br />

output.<br />

We know that the sum df the extern'al forces acting on a certain<br />

volume <strong>of</strong> gas is equal to the vector difference between the Momentum<br />

'<strong>of</strong>' thie gas flowing in <strong>and</strong> the momentum <strong>of</strong> the gas flowing out through<br />

,the control surface limiting this volume, (in hig. 3.18 indicated<br />

.by dashes).<br />

I<br />

250

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