Environmental Engineering Reference
In-Depth Information
changes. Furthermore, during the ventilation of the nacelle, the severe corrosion
on the set possibly caused by blown sand and rain goes against the long-term
secure operation of the set. As the power capacity of the wind generating set keeps
increasing, merely adopting forced air cooling method could not meet the cooling
demands. Hence, liquid cooling systems are emerging.
3.2 Liquid cooling system
From the thermodynamics knowledge, the thermal equilibrium equation of a wind
turbine cooling system can be described as
Q
=
q
m
C
p
(
t
1
-
t
2
), where
Q
is the total
system heat,
q
m
is the mass fl ux of the cooling medium,
C
p
is the mean specifi c
heat at constant pressure of the cooling medium between temperature
t
1
and
t
2
.
t
1
and
t
2
are the inlet and outlet temperature of the cooling medium. As the liquid
medium's concentration and specifi c heat capacity are much greater than that of
the gaseous medium, the cooling system adopting liquid medium can obtain much
larger cooling capability as well as a more compact system structure which can
solve the problem of low cooling output and the enormous size of the air cooling
system. The structure of the cooling system is shown in Fig. 4.
During the operation of a wind turbine, the cooling medium fi rstly fl ows through
the oil cooler, exchanging heat with lubrication oil and taking away the heat pro-
duced by the gearbox. Then it fl ows into the heat exchanger fi xed around the stator
Figure 4: Cooling system adopting liquid cooling method [9]: 1, water pump;
2, oil pump, 3, generator; 4, generator heat exchanger; 5, external
radiator; 6, oil cooler; 7, gearbox; 8, lubricating oil pipeline; 9, cooling
medium pipeline.
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