Working Principle of Exhaust Gas Turbocharger in Diesel Generator
by Starlight Generator dieselgeneratortech1.The
working principle of exhaust gas turbocharger
Exhaust gas turbocharger
is a turbocharger driven by exhaust gas energy from diesel engine, which
compresses air and then feeds it into cylinder. After diesel engine
turbocharging with exhaust gas turbine, the output power of diesel engine can
be increased by more than 30% to 100%. At the same time, it can also reduce the
unit power quality, reduce the shape size, save raw materials, reduce fuel
consumption, increase the torque of diesel engine, increase the load charge
capacity, and reduce the pollution of exhaust to the atmosphere. So it has been
widely used.
2.The
structure of exhaust gas turbocharger
The structure of exhaust
gas turbocharging system in diesel generator is shown in the figure.
The exhaust pipe of
diesel engine is connected to the volute of the turbocharger. The exhaust gas
with high temperature 500℃ to 600℃ and certain pressure
from the diesel engine enters the nozzle ring through the volute, and the
channel area of the nozzle ring gradually decreases from large to small.
Therefore, it can be achieved: although the pressure and temperature of the
exhaust gas are decreasing, but its flow rate is constantly increasing. This
high-speed exhaust gas impacts the turbine in a certain direction to let
pressure, temperature and speed of turbine high-speed rotation exhaust gas
increase, then the faster the speed of the turbine. The exhaust gas through the
turbine is finally discharged into the atmosphere.
3.Turbocharging
form of exhaust gas turbocharger
The exhaust gas
turbocharger can be divided into two types according to the direction of the
air flow entering the turbine: the axial flow type and the runoff type.
The structure of the
runoff turbocharger is shown in the figure.
It mainly consists of
volute, nozzle ring, turbine and rotor shaft etc. When runoff turbocharger
works, the exhaust gas from the diesel engine enters the volute of the
turbocharger and flows vertically along the axis of the turbocharger rotor
shaft, the impeller is forced to change the flow direction along the deaf
curved passage. Under the action of centrifugal force, the particles of air
flow are projected to the N side of the blade, and the pressure increases while
the relative velocity decreases; the relative velocity on the convex side of
the blade increases while the pressure decreases.
When an axial-flow
turbocharger works, the exhaust gas from the diesel engine enters the volute of
the turbocharger, and the airflow flows along the axis of the turbocharger's
rotor axis, so it is called an axial-flow turbocharger.
According to whether the
pulse energy of exhaust gas in exhaust pipe of diesel engine is used or not,
the exhaust gas turbocharge can be divided into constant pressure type and
pulse type.
Constant-pressure
exhaust gas turbocharger is to connect the exhaust manifold of all cylinders of
a multi-cylinder diesel engine to an exhaust manifold and then to the
turbocharger shell. The exhaust gas is directed to the whole nozzle ring along
a single volute intake passage with an average pressure. This turbocharger is
often used in high-power and high-pressure diesel engines.
The schematic diagram of
the exhaust system of the pulse exhaust gas turbocharger is shown in the
figure.
Take six-cylinder diesel
engine as an example, the ignition sequence is 1-5-3-6-2-4, usually, the
exhaust passage of 1,2,3 cylinders are connected to an exhaust manifold, along
an inlet port on the volute to another half ring nozzle ring, so that this
structure can make full use of the pulse energy of exhaust gas.
The main performance
index of the exhaust gas turbocharger is the air pressure rise ratio, referred
to as the pressure ratio. It is expressed as the ratio of the compressor outlet
air pressure “pk” to the compressor inlet air pressure “p1”, that is nk=pk/p1.
The greater the air
pressure at the compressor outlet, the greater the air density entering the
cylinder. Turbochargers can be divided into three types according to pressure
ratio: low turbocharger nk <1.8, medium turbocharger nk=1.7~2.5 and high
turbocharger nk>2.5.
For medium turbocharger
nk>1.8, in order to reduce the air temperature at the outlet of the
compressor and increase the air density entering the cylinder, a low and medium
turbocharged runoff pulsed exhaust gas turbocharger is widely used in diesel
engines. High turbocharged diesel engine has became the development trend.
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manufacturer focuses on providing high quality power generator, cover Cummins,
Volvo, Perkins, Deutz, Yuchai, Shangchai, Doosan etc. If you have purchase
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Created on Sep 9th 2019 23:09. Viewed 337 times.