Question

I know the correct answers for are:

a) 34.36MW

b) 0.741

c) 52.2 MW, 870.3 kj/kg

i am just unsure of the methods.

Question 2 Air enters the compressor of a jet engine at 235 K and 40 kPa, with a flow rate of 60 kg/s and speed of 250 m/s. The exit temperature, pressure and speed are 804 K, 1460 kPa, and 110 m/s, respectively. There is heat transfer from the compressor at a rate of 1.56 MW. The axis of the compressor is horizontal. From the compressor, the air passes to a combustion chamber, where pressure remains constant and temperature rises to 1370 K. Determine the mechanical power input of the compressor (state any assumptions clearly). [14] (а) Draw a T-s diagram for the compression process, and determine the isentropic efficiency of (7] (b) the compressor. Calculate the heat transfer rate and the specific heat transfer rate in the combustion chamber. [4] (e)

Answer 1

que a consider a one compressor with given condition 7 Q = 1.56 mw comp TI =235% P = 40 kpa m = 60K915 VI = 250 MIS to To = 800k T P2 = 1460 kPa v2 = 110 MS com cham Pin Ta = 1370 K assump HOM - is Air is om ideal gas Here using steady Flow energy equation of opon System, mi ( hit wi2 +219) + P =of b2 +12%2529) 4W m 2000 2900 m' < Chi-h2) + (2_123) +(21-22097 = v 2000 Here 1=22 Scanned with CamScanner

0 1005 (935-804) +(250 - 2000 60 - 32.7987x18² 1.584183 = w w = -34.358x103 kW I w=-34.358 mW - Negative sigo mdicates that work given to the compressor. - Honce cocok required to compress wris 34:358 m . be T-S diagoam of compressies 2x < prxess 1-2 - isen bopic compression ideal Tds Scanned with 1-2's actual compression preless CamScanner

77 isentropic officienly nisem - Wison Wactural = T2-T Tal-J1 we already know Tal but ... PRIH T Now Find out T2 PI 0.4 R = 235X / 1480 14 I 40 T2 = 656.80K nisen = 656.80-235 80u - 235 n2 sem = 0.7413 PS Tel . HB supply FLT Heat tooms for Rate Cp0T3=pDT2 + Rs s = (T3-) XCP Qs = 60 (1376-804) as = 34.129 mw speacific heat transfer Rate Scanned with Qspec = 34.129160 = 568.8367715 CamScanner

for speacific heat transfer rate there I taken value of MW so final ans is 568.83Mw/kg.