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mathematical modelling

Predictions of flow, turbulence, heat-transfer and air humidity patterns in operating theatres

Advances in infection control practices include improved operating room environment (airflow velocity, turbulence level, temperature, and relative humidity). Operating theatres are complex spaces. CFD modelling is a powerful tool to enhance the knowledge of the air characteristics. The 3DHVAC program was used to predict the performance of HVAC system design in operating theatres of a 1200-beds Egyptian modern teaching hospital.

CFD Study of the micro-climate around human body with inhalation and exhalation

This paper deals with the CFD (Computational Fluid Dynamics) method used for the analysis of the micro-climate surrounding the human body. The airflow characteristics of inhalation and exhalation are analysed under both steady and unsteady breathing conditions. The various examples given in this report make clear that CFD is a very effective and powerful tool for analysis and design of healthy indoor environments.

Numerical simulation of indoor air quality in a French house: study of the distribution of pollutants in each room, modeling contaminant exposure

The study presented in this article concerns the numerical simulation of airflows and occupational exposure to household contaminants. A finite volume code (CFD) is used to simulate a single-family house with several ventilation, heating, and climatic conditions. The concentration and occupational exposure levels of household contaminants CO2, CO, HCHO, NO2, and water vapour, all from human metabolism, along with those from gas cooking and smoking, are evaluated over a day for a generic occupational schedule of four family members.

Study on the thermal performance and air distribution of a displacement ventilation system for a large space application

The purpose of this study is to clarify the usefulness of a displacement ventilation air-conditioning system introduced into a multipurpose hall after CFD simulation and measurement. In the multipurpose hall of Kurume City, a displacement ventilation air-conditioning system equipped with a floor outlet had been adopted. A CFD simulation for the purpose of selecting an air condition system indicated the floor outlet system would be more effective for the design plan of the hall than a ceiling outlet system.

Numerical and experimental investigations of air-flow and temperature patterns of a low velocity diffuser

In this article, four turbulence models are studied to capture the flow and temperature behavior of the air close to a low-velocity diffuser for displacement ventilation. Turbulence is modeled by means of one zero-equation model and three different two-equation models, i.e. the LVEL, the RNG, the Standard k-e, and the Chen-Kim model. They are evaluated for their performance in predicting the air flow patterns and temperature profiles close to the diffuser.

Room average velocity equation - a tool to improve design of thermal comfort condiitons

For a long time PPD index defined in international ISO7730 standard has been a practical tool for evaluation of measured thermal comfort conditions in existing buildings. However, its usage has not yet been realized in design phase. One of the reasons is that there has not been any practical tool available to estimate average velocity conditions within the occupied zone. A kinetic energy model for calculation of the average room velocity has been presented in earlier paper. Current paper reports additional verification results of the kinetic energy model with different types of diffusers.

A zonal model for predicting simultaneous heat and moisture transfer in buildings

A zonal model was developed to predict temperatures and moisture in a room taking into account the adsorption/desorption by building materials. Results show how adsorption/desorption influences the moisture field.

Numerical calculation of mean radiant temperature and temperature assymmetry for complex room geometry

This paper proposes an algorithm based on the computation of view factors to evaluate the mean radiant temperature in a room with a complex geometry.

Study on the thermal environment in buildings with large-scale atriums and large area of glass surface

The control of thermal environment is complicated in buildings with glass-covered atriums. Numerical simulation can play an important role in the heating, ventilation, air-conditioning (HVAC) design of atriums. Many researches have developed various computational fluid dynamics (CFD) methods to accurately predict the thermal environment in atriums. However, a simple, reliable and fast method to deal with complex building construction is more suitable for building designers and engineers to take as a routine assistant tool of HVAC design.

Modeling particle deposition in ventilation ducts

Two models were applied to predict particle deposition in ducts, one theoretical, the other based on experiments. These models are described and a comparison of their predictions is compared to experimental results.

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