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MAN B&W 6.04
Calculation of L<strong>is</strong>t of Capacities for Derated Engine
Example 1:
MAN B&W S65ME-C8-GI-TII
MAN Diesel
Page 3 of 12
Pump and cooler capacities for a derated 6S65ME-C8-GI-TII with high efficiency MAN Diesel turbocharger
type TCA, fixed pitch propeller and central cooling water system.
Nominal MCR, (L 1 ) P L1 : 17,220 kW (100.0%) and 95.0 r/min (100.0%)
Specified MCR, (M) P M : 14,637 kW (85.0%) and 85.5 r/min (90.0%)
Matching point, (O) P O : 14,637 kW (85.0%) and 85.5 r/min (90.0%), P O = 100.0% of P M
The method of calculating the reduced capacities
for point M (n M% = 90.0% and P M% = 85.0%) <strong>is</strong>
shown below.
The values valid for the nominal rated engine are
found in the ‘L<strong>is</strong>t of Capacities’, Figs. 6.03.01 and
6.03.02, and are l<strong>is</strong>ted together with the result in
the figure on the next page.
Heat d<strong>is</strong>sipation of scavenge air cooler
Fig. 6.04.01 which approximately indicates a Q air%
= 83.1% heat d<strong>is</strong>sipation, i.e.:
Q air,M =Q air,L1 x Q air% / 100
Q air,M = 7,150 x 0.831 = 5,942 kW
Heat d<strong>is</strong>sipation of jacket water cooler
Fig. 6.04.02 indicates a Q jw% = 88.5% heat d<strong>is</strong>sipation;
i.e.:
Q jw,M = Q jw,L1 x Q jw% / 100
Q jw,M = 2,490 x 0.885 = 2,204 kW
Heat d<strong>is</strong>sipation of lube oil cooler
Fig. 6.04.03 indicates a Q lub% = 91.7% heat d<strong>is</strong>sipation;
i.e.:
Q lub,M = Q lub, L1 x Q lub% / 100
Q lub,M = 1,360 x 0.917 = 1,247 kW
Heat d<strong>is</strong>sipation of central water cooler
Q cent,M = Q air,M + Q jw,M + Q lub, M
Q cent,M = 5,942 + 2,204 + 1,247 = 9,393 kW
Total cooling water flow through scavenge air
coolers
V cw,air,M = V cw,air,L1 x Q air% / 100
V cw,air,M = 252 x 0.831 = 209 m 3 /h
Cooling water flow through lubricating oil cooler
V cw,lub,M = V cw,lub,L1 x Q lub% / 100
V cw,lub,M = 183 x 0.917 = 168 m 3 /h
Cooling water flow through central cooler
(Central cooling water pump)
V cw,cent,M = V cw,air,M + V cw,lub,M
V cw,cent,M = 209 + 168 = 377 m 3 /h
Cooling water flow through jacket water cooler
(as for lube oil cooler)
V cw,jw,M = V cw,lub,M
V cw,jw,M = 168 m 3 /h
Seawater pump for central cooler
As the seawater pump capacity and the central
cooler heat d<strong>is</strong>sipation for the nominal rated engine
found in the ‘L<strong>is</strong>t of Capacities’ are 540 m 3 /h
and 11,000 kW the derated seawater pump flow
equals:
Seawater pump:
V sw,cent,M = V sw,cent,L1 x Q cent,M / Q cent,L1
= 540 x 9,393 / 11,000 = 461 m 3 /h
198 74 50-1.0