The noise of diesel
generator mainly comes from diesel engine and generator. In order to reduce the
noise of generator set, the main noise source should be controlled, and the key
to the control is to find the main sound source accurately.
I
Main noise sources of Diesel engines
1.
Intake and exhaust noise
Intake and exhaust noise
is the strongest noise source of diesel engine.
The intake noise is
mainly the pressure pulsation of air in the intake pipe, the low frequency
noise, the high frequency eddy current noise produced by the air flowing
through the inlet valve section at high speed, and the noise of the
turbocharger compressor of the turbocharged diesel engine.
The exhaust noise is
mainly the pressure pulsation of exhaust gas in the exhaust pipe, which
produces low and medium frequency noise, and the high frequency eddy current
noise at the flow section of the exhaust valve.
2.
burner noise
The combustion of
combustible mixture in cylinder causes the rapid change of gas pressure, which
causes the piston, cylinder head, connecting rod, piston pin, crankshaft and
other parts to be subjected to impact load, resulting in structural vibration
and noise.
3.
mechanical noise
Due to the periodic
changes and impact of the forces between the parts of the diesel engine, the
surface vibration produces noise. The mechanical noise increases rapidly with
the speed of the engine. The main parts of the mechanical noise are piston, cylinder
head, cylinder block, cylinder liner, connecting rod, piston pin, crankshaft,
valve train, gear, spray. The design of the components, the quality of the
manufacturing and the selection of materials have an important effect on the
noise. The structural stiffness of the diesel engine, the speed of the engine
and the clearance of the moving parts are the main factors affecting the
mechanical noise.
II
Main noise sources of generators
1.
ventilation noise
Electromagnetic noise is
caused by the interaction of stator and rotor magnetic field in the air gap of
generator to produce radial force varying with time and space, which causes the
stator core and seat to deform periodically and cause vibration and noise.
2.
electromagnetic noise
Electromagnetic noise is
caused by the interaction of stator and rotor magnetic field in the air gap of
generator to produce radial force varying with time and space, which causes the
stator core and seat to deform periodically and cause vibration and noise.
3.
mechanical noise
The mechanical noise of
generator includes mechanical vibration and noise caused by centrifugal force
caused by rotor mechanical imbalance, vibration noise of bearing, sliding
contact noise of brush collector ring or commutator, axial vibration noise of end
cover excited by bearing vibration.
Comments
Post a Comment