Mechanical Engineering - Compressors, Gas Dynamics and Gas Turbines - Discussion

To determine the delivery pressure at the fourth stage, let's assume the compression ratio is the same for each stage. This is a common approach in multi-stage compression.

Given:
- Stage 1 pressure (P1) = 1 bar.
- Stage 3 pressure (P3) = 16 bar.

Let's find the compression ratio per stage (R). If P1 is the suction pressure of the first stage and P2 is the discharge pressure of the first stage (which becomes the suction pressure for the second stage), and so on:

P2 = P1 * R.
P3 = P2 * R = P1 * R^2,
16 = 1 * R^2.
R^2 = 16.
R = 4.

Now, let's find P4 (discharge pressure of the fourth stage):

P4 = P3 * R = 16 * 4 = 64 bar.

So, the delivery pressure at the fourth stage would be 64 bar.

Let r be the pressure ratio.
P2 =P1 x r.
P3 = P1 x r^2 (P3 and P1 are given, we can find r).

r^2 = P3/P1 = 16/1 = 16,
r = 4.

Delivery pressure at fourth stage P4 = P1 x r^3
= 1 x 4^3 = 64.

@All.

The pressure mentioned in the question are the Delivery pressure. If we assume P2 as 1 bar and P4 as 16 bar, then only P5 comes as 64 bar.

The delivery pressure at the fourth stage means p5.

So p1 is 1.
P2 is 4.
P3 is 16.
P4 is 64.
P5 is 256.

So option D. 256 should be correct.

Good explanation, thanks @Suresh.

P2/p1 = p3/p2 = p4/p3 By using this we will get the answer.

In third stage, why intercooler isb fitted. And how the pressure is increasing? Can anyone briefly destribe about this topic?

Thanks @Suresh.

D is the answer.

The answer must be" D".

Because delivery pressure at the fourth stage means we should find P5, not P4. So P5 = 4^4.