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- Aircraft cabin air flow (1)
- Computational fluid dynamics (1)
- Faser-Kunststoff-Verbunde (1)
- Gas mixtures (1)
- Model validation (1)
- Schubfestigkeit (1)
- Schubrahmen (1)
Using plastic jerrycans or plastic containers, dangerous goods are transported as air freight in commercial aircrafts. Liquids or gases can escape by leakage or permeation effects from these plastic containers. The German Federal Institute for Materials Research and Testing (BAM) conducted prior research which showed that the lower explosion limit can be reached when transporting dangerous goods in sea-freight containers under normal transportation situations. The presented study is motivated based on these findings. The research objective of this study is to analyze the transportation situation of dangerous goods in cargo compartments of commercial airplanes. The scope of this paper is to present the experimental method used for validating a numerical model for CFD (Computational Fluid Dynamics) simulations and to present some simulation results of the mass transport of dangerous goods in the cargo compartment.
The velocity profiles and the mass transport is calculated using numerical simulations and measured by Laser-Doppler-Anemometry (LDA) experiments. The mock-up is a generic model of a wide-body aircraft lower deck cargo compartment in a 1: 10 scale. Geometry, air exchange rates and inlet as well as outlet flow conditions in the cargo compartment are modeled using realistic boundary conditions. The commercial CFD (Computational Fluid Dynamics) code ANSYS CFX 14 is used for numerical flow simulations applying RANS (Reynolds-Averaged-Navier-Stokes) equations and turbulence models. The turbulence models studied are the renormalization group k-e-model (RNG), the BSL-Reynolds-Stress model (BSL) and the SST-k-co-model by Menter (SST).
The flow measurement with LDA in the mock-up of a cargo compartment proves to be a feasible method for producing data to validate CFD simulations. Qualitative evaluation of the results shows a good overall agreement between numerical and experimental results. The experimental validation indicates that the implemented CFD model is capable of reproducing the flow situation in the model mock-up
Für die Schubkennwertermittlung an faserverstärkten Kunststoffen existieren verschiedene Verfahren, die nur eine Prüfung bis zu einer vorgegebenen maximalen Schubdehnung zulassen. Die Grasse Zur Ingenieurgesellschaft hat auf Basis eines an der BAM entwickelten Schubrahmens ein Schubprüfsystem etabliert, das diese Nachteile aufhebt. Damit ist es nun erstmals möglich, Schubkennwerte ohne Einschränkung einer maximalen Schubdehnung effizient und mit sehr guter Reproduzierbarkeit zu ermitteln.
Dangerous goods are transported as air freight in commercial aircrafts. Using plastic jerrycans or plastic containers, liquids or gases can escape by leakage or permeation effects. Prior research by the German Federal Institute for Materials Research and Testing (BAM) showed that the lower explosion limit can be reached when transporting dangerous goods in sea-freight containers under normal transportation situations. This motivated the presented study of the transportation situation of dangerous goods in cargo compartments of commercial airplanes. The scope of this paper is to present the experimental method used for validating a numerical model for CFD (Computational Fluid Dynamics) simulations. The CFD model will be used in a future study to evaluate the potential risk from transporting dangerous goods.
The objective of this paper is to present the model mock-up of an aircraft cargo compartment and some examples of three dimensional velocity profiles of the air flow in the mock-up. The velocity profiles are calculated using numerical simulations and measured by Laser-Doppler-Anemometry (LDA) experiments. The mock-up is a generic model of a wide-body aircraft lower deck cargo compartment in a 1:10 scale. Geometry, air exchange rates and inlet as well as outlet flow conditions in the cargo compartment are modeled using realistic boundary conditions. The commercial CFD (Computational Fluid Dynamics) code ANSYS CFX 14 is used for numerical flow simulations applying RANS (Reynolds-Averaged-Navier-Stokes) equations and turbulence models. The turbulence models studied are the renormalization group k-ε-model (RNG), the Reynolds-Stress model by Launder, Reece and Rodi (LRR) and the SST-k-ω-model by Menter (SST).
The flow measurement with LDA in the mock-up of a cargo compartment proves to be a feasible method for producing data to validate CFD simulations. Qualitative evaluation of the results shows a good overall agreement between numerical and experimental results. The experimental validation indicates that the implemented CFD model is capable of reproducing the flow situation in the model mock-up.
Für die Bewertung der Integrität von Tanks ist die detaillierte Kenntnis der belastungsrelevanten Parameter unabdingbar. Die Wärmeübergangszahl a ist eine derartige Größe. Die Wärmeübergangszahl bestimmt direkt die Größe der vorhandenen Beanspruchungen im Tank. Insofern sollte die Wärmeübergangszahl bekannt sein. Aus diesem Grund wurden experimentelle Untersuchungen durchgeführt. Für einen sich im Feuer befindlichen Tank ergibt sich die Wärmeübergangszahl zu 50 W/m2K. Auf dieser Basis konnten die bereits durchgeführten experimentellen Untersuchungen mithilfe der Methode der finiten Elemente nachgerechnet werden. Die dabei erzielten Ergebnisse sind infolge der getroffenen modelltechnischen sowie thermodynamischen Vereinfachungen als zufriedenstellend zu bezeichnen. In einem nächsten Schritt wird an einer verbesserten Modellierung sowie thermodynamischen Beschreibung der Verhältnisse im Tank gearbeitet.