This article describes CFD simulation results and measurements using a swirl diffuser. Thediffuser is able to provide relatively low velocities within the occupied zone while supplying high airflow rates. The flow pattern produced by the air diffuser was validated by measurements with a flow rate of 133 l/s and 4 C lower temperature than ambient air. Turbulence was modelled using the RNG k- e model with additional swirl modification.
This paper describes a comparison between internal and external run-time coupling of CFD and building energy simulation software. Internal coupling can be seen as the traditional way of developing software, i.e. the capabilities of existing software are expanded by merging codes. With external coupling, two or more software packages run simultaneously while exchanging calculation results at appropriate time intervals.
This paper outlines the extension of a CFD model using DBM modelling approach. Primarily adynamic CFD model is proposed for adiabatic ventilation system. At the inlet a step rise in temperature of the incoming air with steady flow rate is used for the CFD simulation and temperature responses at 36 monitoring locations were extracted. In the second stage, the inlet and the extracted temperature profiles were used to develop DBM models at individual locations. Finally the developed compact DBM model was used to construct model based predictive control algorithm.
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.
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.
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.
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.
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.
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.
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.