Local Exhaust Efficiency in an Operating Room Ventilated by Horizontal Unidirectional Airflow

The paper examines the efficiency of a local exhaust applied during an orthopaedic surgicaloperation. During operations performing hip replacements bone cement is sometimes applied to fasten the new metal hip to the existing thighbone, especially in case of elderly patients. The bone cement emits harmful VOCs that may influence the operating room personnel and the patient. A local exhaust is applied to reduce the VOC concentration in the operating room air, however, apparently without success.

Application of Simple CFD Models in Smoke Ventilation Design

The paper examines the possibilities of using simple CFD models in practical smoke ventilationdesign. The aim is to assess if it is possible with a reasonable accuracy to predict the behaviour of smoke transport in case of a fire. A CFD code mainly applicable for ordinary ventilation design is used for the examination. The CFD model is compared with benchmark tests and results from a special application fire simulation CFD code. Apart from benchmark tests two practical applications are examined in shape of modelling a fire in a theatre and a double faade, respectively.

About the validity of turbulence models for the computational fluid dynamics of a non-isothermal developing plane jet in aiding mixed convection regime

A comparative study between experiments and numerical simulations in the developingzone of a non-isothermal plane vertical jet is presented. Low velocity airflow, in aiding mixedconvection regime, discharging from a large rectangular nozzle in a quiescent medium at a highertemperature is considered (Re = 4220).The "Reynolds-Averaged" Navier-Stokes equations (RANS) are solved with two codes, the CFD code Fluent and the Aquilon code, including different turbulence models.

Computation and Representation of Fire and Smoke in Buildings

The conversion of CAD models into 3D Cartesian-defined geometries is presented, and a two-pass algorithm to perform the transformation is described. The methodology for implementing the numerical solution of fire dynamics problems involving the FDS simulation program is tested. The results from these predictions are visualized on the original geometry using elements which take into account the optical properties of the phenomena for a realistic rendering of smoke and fire.

Zone Resistance in Embedded CFD Modeling

Seeking to realistically model details of room airflows, researchers have recently embeddeddetailed CFD or sub-zone (zonal) models within multi-zone idealizations of building systems. However a number of issues remain to be resolved to assure the success of this approach. Foremost is the question of zone resistance which is ignored in multi-zone models yet implicitly included in CFD and sub-zone models.This paper defines a fundamental means to measure zone resistance and presents the results of CFD studies to evaluate its relative significance for representative geometries.

Prediction of indoor airflow patterns in livestock building ventilated through a diffuse ceiling

The airflow conditions in an experimental pig housing unit are examined both experimentally and numerically (simulation) with particular focus on the airflow conditions in the occupational zone of the animals. Two heating setups are used, and the temperature is measured in a horizontal profile at the floor and at the ceiling. Good concordances between the measurements and the simulations are reached at the floor level. At the ceiling level, the conformity to the measuring results is unsatisfactory.

Analysis of Capture Efficiency of a Ventilated Ceiling

The capture efficiency of the total system must be guaranteed so that the spread of impurities throughout the kitchen is prevented. A capture efficiency model is derived and it is used to estimate the efficiency of a ventilated ceiling. This paper demonstrates that a simple equation that includes the average contaminant level in the occupied zone and the exhaust concentration could be a suitable platform for capture efficiency analysis in both measurements and simulations.

Ventilation and Smoke Simulation in Cargo Holds and Engine Rooms on board of RORO-Ferries

Ships are very demanding on the ventilation systems that need to be installed. The reasons forthis are manifold. The following paper will address the problems around the ventilation layout for a typical RoRo-Ferry and will show how CFD can help the designers to optimize the system. One new area of interest is the simulation of fire to optimize the fire suppression systems in engine rooms of RORO vessels.

Reinforced Exhaust System with Slot Exhaust Hood

The paper deals with research on capture efficiency of reinforced exhaust system equipped withhorizontal slot exhaust hood, capture efficiency of which is increased by radial flow of supply air through a slot in hood flange. Investigation was carried out with the use of tracer gas method applied in order to measure the capture efficiency of the system, interferometric method in order to visualize tracer gas propagation from different sources, and smoke method in order to make flow patterns at exhaust system visible.

Comfort simulation of a double-deck train coach using CFD analysis

Within the last years CFD has become an essential tool to investigate and optimize concepts of train coaches during an early design stage to achieve best results without major modifications of the final design. The simulation of the current railroad double deck coach gives some special challenges because of the complex channel system and the different boundary conditions on each floor. First the air duct including the outlet vents is investigated and optimized. The results are used as boundary condition for the simulation of the passenger's compartment.

Pages