An acoustic one-dimensional compressor model has been developed.
This model is based on compressor map information and it is able to
predict how the pressure waves are transmitted and reflected by the
compressor. This is later on necessary to predict radiated noise at
the intake orifice. The fluid-dynamic behavior of the compressor
has been reproduced by simplifying the real geometry in
zero-dimensional and one-dimensional elements with acoustic
purposes. These elements are responsible for attenuating or
reflecting the pressure pulses generated by the engine. In order to
compensate the effect of these elements in the mean flow variables,
the model uses a corrected compressor map. Despite of the fact that
the compressor model was developed originally as a part of the
OpenWAM™ software, it can be exported to other commercial wave
action models. An example is provided of exporting the described
model to GT-Power™.
The model has been validated using experimental results obtained
in a turbocharger test bench under pulsating flow conditions. The
characteristics of the pressure waves (amplitude, frequency and
mean flow) are similar to those of the pulses that the compressor
undergoes when working coupled to a reciprocating internal
combustion engine. This facility allows wave decomposition upstream
and downstream of the compressor. The experimental pressure waves
have been compared versus the results provided by the model
analyzing both in frequency domain and in time domain in the two
codes used to host the model. Finally, a comparison between the
proposed 1D-0D model, which furthermore applies the compressor map,
and the standard methodology used by GT-Power™, which directly
only interpolates in the compressor map, has been performed.
Results show better performance in the case of the proposed model
and evidence the interest for the compressor geometrical
description.