Mikhail Konstantinov

Numerical Simulation of the Thermal Comfort in a Model of a Passenger Car Cabin

Results of numerical simulations of the air flow including the heat transport, the thermal radiation and the thermal comfort of passengers in a model of passenger car cabin are presented. The computations have been performed by coupling flow simulations conducted with the Computational Fluid Dynamics (CFD) code OpenFOAM with simulations of the heat transport within the passengers using the finite-element code THESEUS-FE. The latter takes into account effects like blood flow, heat transfer through the skin and clothing as well as activity levels and ambient humidity in various layers with different heat transport characteristic. Based on these simulations four different ventilation variants known from the ventilation of aircraft cabins are analysed with respect to their performance regarding the thermal comfort of passengers and the their energy efficiency in future electric cars.

Numerical Simulation of the Air Flow and Thermal Comfort in Aircraft Cabins

Results of a numerical study of the air flow and the thermal comfort of the passengers in an aircraft cabin which includes thermal radiation effects are presented. The computations have been performed by coupling flow simulations with the Computational Fluid Dynamics (CFD) code OpenFOAM with finite element simulations of the heat transport within the passengers using the code THESEUS-FE. With the latter the bodies of passengers are modeled based on various layers with different heat transport characteristics to account for effects like blood flow, skin, clothing as well as activity levels and ambient humidity. Computations of the flow, the thermal radiation and the modeled passenger comfort in the cabin of the Airbus A320 and Do728 are discussed. The predicted numerical temperature distributions in the cabin of Do728 have been supported by experimental measurements.

Sound Generation by Low Mach Number Flow Through Pipes with Diaphragm Orifices

Aerodynamic noise generated by low Mach number flow through a pipe with two differently sized diaphragm orifices is investigated both theoretically as well as numerically. Such a flow may be considered as a simple model of an aircraft climate control system. The theory is based on an acoustic analogy introduced by Mohring and Obermeier in the seventies. They identified by means of the so-called Green’s vector function acoustic sources in unsteady flows as the unsteady motion of vorticity “vortices are the voice of flows”. In addition, the unsteady flow through the pipe, the aerodynamic sources, and the spectra of sound are evaluated numerically. Here effects of different numerical algorithms (PISO—PIMPLE) and of different numerical boundary conditions at the outlet of the pipe (advective, convective—wave transmissive) are identified and discussed.

Numerical Simulation of the Sound Generation and the Sound Propagation from Air Intakes in an Aircraft Cabin

The paper presents results of unsteady Reynolds-averaged Navier-Stokes simulations (URANS), Delayed Detached Eddy Simulations (DDES) and Large Eddy Simulations (LES) of the flow and the noise propagation in a segment of the DLR’s cabin test facility Do728. Since the weakly compressible Navier-Stokes equations were solved in all cases, spectra of the sound pressure levels (SPL) were analyzed based on Fast Fourier Transforms of the predicted pressure fields. It was shown that LES on hexahedral meshes predict SPLs in good agreement with microphone measurements in the Do728 cabin. A comparison with predictions based on a hybrid approach involving the solution of a wave equation together with non-reflective boundary conditions on the one hand, and a Ffowcs Williams-Hawkings (FW-H) model on the other hand, revealed that the impact of the imperfect acoustic boundary condition in the LES on the sound pressure level at the receiver point is negligible. Thus, it was demonstrated that reliable predictions of SPLs in an aircraft cabin are possible if the corresponding LES can be performed.