Man B&W S80ME-C7 User Manual

S80ME-C 198 43 95-7.1
MAN B&W Diesel A/S 6.04
Page 3 of 12
Calculation of List of Capacities for Derated Engine
Example 1:
Pump and cooler capacities for a derated 6S80ME-C with high efficiency MAN B&W turbocharger,
type TCA with fixed pitch propeller and central cooling water system.
Nominal MCR, (L
1
)P
L1
: 23,280 kW (100.0%) and76.0 r/min (100.0%)
Specified MCR, (M) P
M
: 18,624 kW (80.0%) and 68.4 r/min (90.0%)
Matching point, (O) P
O
: 16,762 kW (72.0%) and 66.0 r/min (86.9%), P
O
= 90.0% of
PM
The method of calculating the reduced capacities
for point M (n
M%
= 90.0 and P
M%
= 80.0) is shown
below.
The values valid for the nominal rated engine are
found in the ‘List of Capacities’, Figs. 6.03.01 and
6.03.02, and are listed together with the result in
the figure on the next page.
Heat dissipation of scavenge air cooler
Fig. 6.04.01 which approximate indicates a Q
air%
=
75.0% heat dissipation, and corrected for match-
ing point O lower than M, by applying correcting
factor k
O
, equal 75.0 x (1 + 0.27 x (1 – 0.900)) = 77.0%
i.e.:
Q
air,M
=Q
air,L
1
x Q
air%
/ 100
Q
air,M
= 9,090 x 0.770 = 6,999 kW
Heat dissipation of jacket water cooler
Fig. 6.04.02 indicates a Q
jw%
= 84.2% heat dissipa-
tion; i.e.:
Q
jw,M
= Q
jw,L
1
x Q
jw%
/ 100
Q
jw,M
= 3,430 x 0.842 = 2,888 kW
Heat dissipation of lube oil cooler
Fig. 6.04.03 indicates a Q
lub%
= 91.2% heat dissipa-
tion; i.e.:
Q
jw,M
= Q
jw,L
1
x Q
jw%
/ 100
Q
lub,M
= 1,750 x 0.912 = 1,596 kW
Heat dissipation of central water cooler
Q
cent,M
= Q
air,M
+ Q
jw,M
+ Q
lub, M
Q
cent,M
= 6,999 + 2,888 + 1,596 = 11,483 kW
Scavenge air coolers:
V
cw,air,M
= V
cw,air,L
1
x Q
air%
/ 100
V
cw,air,M
= 306 x 0.770 = 236 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
= 244 x 0.912 = 223 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
= 236 + 223 = 459 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
= 223 m
3
/h
Seawater pump for central cooler
As the seawater pump capacity and the central
cooler heat dissipation for the nominal rated engine
found in the ‘List of Capacities’ are 700 m
3
/h and
14,270 kW the derated seawater pump flow equals:
Seawater pump:
V
sw,cent,M
= V
sw,cent,L
1
xQ
cent,M
/Q
cent,L
1
V
sw,cent,M
= 700 x 11,483 / 14,270 = 563 m
3
/h

Man B&W S80ME-C7 Specifications

General

Brand	Man
Model	B&W S80ME-C7
Category	Engine
Language	English