Question

The plane is powered by 4 four-stroke engines running at n=5210rpm. Total effective power of the engines is (table 2). Swept volume of the engine V, = 3,21, mass air flow rate is mar = 0,21. Calorific value of the fuel CV = 44 mechanical efficiency nm = 91%, specific fuel consumption b; = 0,0812W Ambient temperature and pressure are po and T, (table 2). specific gas constant R = 287 k = 1,4. Calculate: Torque Indicated efficiency Mean effective and indicated pressure Volumetric efficiency Overall efficiency

Answer 1

Solution Given - 832KW = 3.2 l = 3.28103 m² (is 4 stroke Engine i N 5210 5210rpm (ii) Total Effective power () Swept volume (VS) mair = 0.21 kgfs (vi) Calonfic value (CV) of feel = 44000 kg/kg (vii) mech = 91% (vill) Sp. fuel consumption ( Brake) Ishon (ix) Po = 919 69.9267 Pa or 91.969 kPa -0.0812 Hws To = 9.74°C (xi) K=164 & R = 287 9/kg-t To calculate - (i Torque (i) Indicated thermal Efficiency (i) Mean effective Pressure (iv) Indicated Pressure volumetric Efficiency (vi) Overall efficiency.

832kW Analysis we have BP or total effective power (This is the power at the Engine shaft) |BP = 2INT 60 832 - 2 NXT 60x1ooo Torque 1524.95 Nom رأ 832x60x1000 2XTTY 5210 (U) Brake Sp. heel consumption (BSFC) me (Kg/s) BP (kW) 0.0812 -MWOS BP (мы) 0.0812 X 832 x103 = ME (Kg/s) 0.0675kgfs me = 0.0675k Now Amech BP IP 832 0.gi= BR 6. Il = 832 adla 0.91 IP - 914.3 kW

Therefore, IT IP IT Heat supp IP MF (Kgls) & cv (kJ/kg) 914.3 0.0675X 44000 Am. 30.789). 11 - 914.3 2970

(1) Indicated power er - Print Vs x H xk 914.30 1oox Pm x 3.21103 5210 2 60 65.80 bar dro. t Indicated Pressure Brake power = 1oox Prmx Vs x Nxk liu 60 832 - 100x Pm x 3.2410~3 x 5210 5240 x ] 60 Pro = 59.88 bar da. Mean effi Pressure ( V) vol Actual volume Theo. swept volime Calculating dewrity of air Po = &R To 91969.9267 = 3*287* 19.44 +243)

Sair 919 69.9267 28+ x (9.44+373) Sair 1.13 kg/m² now air fuel ratio ma 0:3) = 3.11 MF 0.0675 air consumption / min mair (kg/eun) 0.21x60 Sair (Kg/m?) (Kgfonin) 11.15 m² lamun 1013 [kg]m) air consumptions mis Now Engine Suction volume per minute (K=1) - Vs x Nxk 3.28103 x 5210x1 = 8.336 m² / ww 2 Vactual . Evolumetric - 8 -336 theo. 74.76% . Overall efficienny = volt a mech - 0.7476X Oog 0.68 % do.
thank you.