Sagnik Mazumdar

State-of-the-art methods for studying air distributions in commercial airliner cabins

Abstract Air distributions in commercial airliner cabins are crucial for creating a thermally comfortable and healthy cabin environment. This paper reviews the methods used in predicting, designing, and analyzing air distributions in the cabins, among which experimental measurements and numerical simulations are the two popular ones. The experimental measurements have usually been seen as more reliable although they are more expensive and time consuming. Most of the numerical simulations use Computational Fluid Dynamics (CFD) that can provide effectively detailed information. Numerous applications using the two methods can be found in the literature for studying air distributions in aircraft cabins, including investigations on more reliable and accurate models. The review in the paper shows that the studies using both experimental measurements and computer simulations are becoming popular. And it is necessary to use a full-scale test rig to obtain reliable and high quality experimental data. What’s more, the hybrid CFD models are found to be rather promising for simulating air distributions in airliner cabins.

A one‐dimensional analytical model for airborne contaminant transport in airliner cabins

UNLABELLED Quick information on airborne infectious disease transmission in airliner cabins is essential to reduce the risk of infection of passengers and crew members. This investigation proposed a one-dimensional analytical model that can predict the longitudinal transmission of airborne contaminants or disease viruses inside an airliner cabin. The model considered both diffusive and convective transport of contaminants in the longitudinal direction of the cabin but assumed complete mixing of contaminants in the cabin cross-section. The effect of recirculation of the cabin air and efficiency of the high-efficiency particulate air (HEPA) filters is also considered in the model. The analytical solution for the one-dimensional contaminant transport model is obtained by using the principle of superposition and the method of separation of variables. The analytical solutions agree well with the computational fluid dynamics (CFD) results. The coupling of a CFD model with the one-dimensional analytical model could capture the impact of local airflow on contaminant transport. This analytical model has been used for analyzing contaminant transport in a 30-row all-economy-class airliner cabin with minimal computing effort. PRACTICAL IMPLICATIONS The paper presents a new one-dimensional analytical model that can provide quick information on global airborne contaminant transmissions in airliner cabins for effective response plans. The model can be used to study the effects of air exchange rates, recirculation, efficiency of the high-efficiency particulate air (HEPA) filters and longitudinal airflow on airborne contaminant transport in airliner cabins with minimal computing effort.

Dynamic Performance Analysis of a Compressor Driven Metal Hydride Cooling System

Though several studies have been reported to show that compressor driven metal hydride cooling systems are competitive with conventional vapor compression systems, an elaborate computational model that takes into account the transient nature of the compressor and the conditioned space is still unreported. The results presented here are obtained for a room air conditioner with Zr0.9Ti0.1Cr0.55Fe1.45 as the hydrogen absorbing material and employing standard heat exchanger configurations. Though previous thermodynamic and transient studies predicted attainment of significant coefficients of performance, the present results indicate that even with the optimal design the maximum coefficient of performance and specific power will be around 2.38 and 750kJ∕kg-alloy.h, respectively. This indicates a need for better materials and effective control strategies so that these systems can become commercially viable.

A coupled computational fluid dynamics and analytical model to simulate airborne contaminant transmission in cabins

A coupled computational fluid dynamics (CFD) and analytical model is presented for accurate and time-efficient prediction of transient airborne contaminant transmission in full-length airliner cabins. The CFD model was used at locations near the contaminant source, while the analytical model was used for the rest of the cabin. The CFD and analytical model coupling used two different methods for solving the transient contaminant flux. One method forced an outflow condition at the interface of the CFD; this analytical model is less accurate but easier to implement in commercial CFD software. The other method that iteratively solved the contaminant flux at the interface is more accurate but is computationally intensive. A procedure to analytically calculate the contaminant concentration using the transient contaminant flux condition at the interface was also developed.

Compressor Driven Metal Hydride Cooling Systems: Simulation and System Dynamics

A comprehensive mathematical model to study the performance parameters of compressor driven metal hydride systems is presented. The dynamics of the compressor and the conditioned space has been taken into account. The model also accommodates the transient nature of the external fins. The effect of size and geometry of the heat exchanger has been given due importance while calculating the external heat transfer coefficient of the metal hydride reactors. A 1 TR system is designed using MmNi4.5 Al0.5 as the metal hydride and its operating characteristics are studied. The average COP and SP power obtained are around 3.1 and 125 W/kg respectively. It is seen that compressor remains idle for 30% of the time during stable cycling. The problem of large initial compressor loads during cut-in as is encountered in vapour compression systems are not faced in such systems. Moreover the compressor is not overloaded during sudden load changes.Copyright