Simulation of the performances of engines with various schemes of turbocharging

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Simulation is illustrated on the examples:
- Calculation of the torque performance of a medium speed marine diesel engine with two-stage free turbocharger.
- Calculation of the high-altitude and adjusting performances of the supercharged airplane petrol engine.
- Calculation of the performance of a centrifugal compressor.

The torque performance of a medium speed marine diesel engine with two-stage free turbocharger and air intercoolers.[o- experiment; --- calculation]

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h tk is efficiency of turbocharger.
Pkhp, Tkhp are second stage compressor discharge pressure and temperature.
Pklp, Tklp are first stage compressor discharge pressure and temperature.
Pr, Tr are turbine inlet pressure and temperature.
rpm tklp , rpm tkhp  are rotation speed of turbocharger rotors (of stages of low and high pressure).

Ne is load.

Gair is air flow rate through the engine.
Pz is maximum cylinder pressure.
a   is air fuel ratio.
be is specific fuel consumption.

The calculation of parameters of turbines and compressors of stages of high and low pressure was carried out by means of gas-dynamic calculation of gas flow inside the blading of these machines in view of losses depending on attack angles and gas parameters.

The high-altitude performance of the petrol engine of a light airplane. The engine is equipped with the centrifugal compressor which rotates by the shaft of the engine.

hardav_v.gif (3576 bytes) The performance is designed in view of change of pressure, temperature and airspeed  depending on height and speed of flight (150 km / hour). The law of regulation of fuel supply is: a=0.77=Const. The regime is: "maximum long" rpm=2600.

Ne is load.
be is specific fuel consumption.
Tw is average temperature of the piston.
Pk is boosting pressure.

The adjusting performance of the petrol engine of a light airplane. The engine is equipped with the centrifugal compressor which rotates by the shaft of the engine.

The performance is designed for a choice of an air fuel ratio a and gear number of speed-reducer i of the compressor drive with the purpose of determination of an opportunity and ways of   engine boosting on a flight regime (rpm=2750) by 20 kW.
As indicated by the arrows, the direction of increase
i and decrease a will allow to increase capacity Ne without essential increase of average temperature of the piston Tw

The calculation of parameters of the compressor was made by interpolation of a field of its characteristics which were obtained by  manufacturer.

The characteristic curves of the centrifugal compressor of supercharger TKR-14.

tkr_har.gif (3543 bytes) Results of calculation of a field of the compressor characteristic curves. 

The calculation of parameters of compressors was carried out by means of gas-dynamic calculation of gas flow inside blading in view of losses depending on attack angles and gas parameters.

The fields of the characteristic of compressors and turbines can be given as a textual file of data, or are calculated in a program DIESEL-2/4t on the sizes of its blading part in view of  losses.

 

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