computational fluid dynamics

Wind-driven single-sided ventilation (SSV) is present in many existing buildings across Europe and with new Near Zero Energy Building (NZEB) regulations for the refurbishment of the existing building stock, its attractiveness as a non-invasive, low energy solution is set to continue. As a strategy, however, in addition to its air change rate capacity, the distribution of fresh air is an important evaluating criterion for its performance.

Building energy simulation (BES) and Airflow network (AFN) programs generally incorporate wind pressure coefficients (Cp) estimated from secondary sources, namely data bases or analytical models. As these coefficients are influenced by a wide range of parameters, it is difficult to obtain reliable Cp data. This leads to uncertainties in BES-AFN models results, especially for naturally ventilated building studies, where air change rate which strongly depends on Cp, is a key value for thermal comfort and energy consumption results.

The use of open-source CFD has been growing in both industry and academia. Open-source CFD saves users a considerable license cost and provides users with full transparency of implementation and maximum freedom of customization. However, it is often necessary to assess the performance of an open-source code before applying it to the practical use. This study applies one of the most popular open-source CFD codes – OpenFOAM to the indoor airflow and heat transfer prediction. The performance of OpenFOAM is evaluated and validated against a well-documented benchmark test.

Diffuse ceiling ventilation uses perforations in the suspended ceiling to deliver air into the occupied zone. Due to the complex geometry of the diffuser, it is not possible to build an exact geometrical model in CFD simulation. Two numerical models are proposed in this study, one is a simplified geometrical model and the other is a porous media model. The numerical models are validated by the full-scale experimental studies in a climate chamber.

Airborne particles released from surgical team members are major sources of surgical site infections (SSIs). To reduce SSI risk, ultraclean-zoned ventilation (UZV) systems have been widely applied, supplementary to the main operating theatre (OT) ventilation. Usually, OT ventilation performance is determined without considering the influence of staff-member posture and movements. Whether the surgeon’s posture during surgery influences particle distribution within the surgical area is not well analysed and documented.

Ventilation plan for smoking room must deal with pollutants since they affect the air quality of adjacent rooms. Although ventilation plan typically maintains a negative room pressure to remedy this problem, the transport of indoor air pollutants between rooms is affected by moving objects, such as human movement and door opening. The purposes of this study were to evaluate the effects of moving objects on the rate of transport of indoor air pollutants and to propose a method of controlling contamination for smoking room.

As the benefit of natural ventilation in reducing operational cost is well recognised, the concept of natural ventilation is becoming more received by residents and designers alike.

Corporate tenants require ever-greater design certainty with respect to all aspects of proposed developments. Because of this, its relative novelty and a design methodology that differs from ceiling-based Variable Air Volume (VAV) air conditioning, Under Floor Air Distribution (UFAD) has faced significant scrutiny. Building simulation offers methods to understand the implications of design decisions.

The transient accessibility of supply air (TASA) and transient accessibility of contaminant source (TACS) in ventilated rooms are important indices to evaluate the effect of ventilation and the indoor air quality (IAQ). These indices can be measured by experimental method or calculated with computational fluid dynamics (CFD) tools. Compared to the measurement method, the numerical method has a lot of advantages such as fast, flexible and with detailed data. In this paper, the calculation and validation of the TASA and TACS are introduced.

In the design of indoor winter sports facilities Computational Fluid Dynamics (CFD) simulations are used to calculate the velocity and temperature distribution throughout the space, in order to complement traditional mechanical design and increase confidence into the proposed design. This process is described here using the example of a competitive curling rink. In the introduction the capabilities and limitations of CFD simulations are briefly lined out. The physics of the model of the curling venue are described.