This paper introduces a research programme investigating the application of CFD to large scale industrial premises. A number of modelling issues and two case studies are discussed. The research programme will lead to an increased degree of confidence of CFD simulation results in complicated environments.

A series of CFD and model experiments were carried out in order to find the most effective ventilation system in a separated refuse disposal facility. The ventilation system needed in the facility protects the working space from dust and odors generated by handling refuse. The desired ventilation system is to introduce the outdoor air from the one side of the working area and to exhausts the contaminated air through the opposite side of the refuse stock yard, so-called the unidirectional airflow ventilation.

The keeping of animals in livestock buildings requires the ventilation of these buildings. Good climate conditions for the animals have to be guaranteed as well as little emissions and immissions from the livestock buildings. An important role for both of these opposite requirements plays the airstream inside and outside of the building. For this reason wind tunnel modelling and digital imaging by using a laser light sheet is applied beside other methods at the Institute of Agricultural Engineering Bornim.

In modem livestock buildings the design of the ventilation systems is important in order to obtain good air distribution. The use of Computational Fluid Dynamics for predicting the air flow and air quality makes it possible to include the effect of room geometry, equipment and occupants in the design of ventilation systems. However, it is not appropriate to include the detailed geometry of a large group of lying or standing animals affecting the air flow in the building. It is necessary to have relatively simple models of the animals, which are easier to implement in the computer models.

Under the conditions that the air in each room is in the state of perfect mixing and ventilation is in steady state, a method to estimate steady state concentration distribution to match an arbitrary contaminant generation distribution is proposed, using concentration data obtained from short-time tracer gas experiment. Also, a method is proposed, which is used to estimate ventilation rate by adding other available equations.

A data acquisition system which uses a computer provides a more useful analysis system. Since the processing speed of computer is continuously increasing, the information than it is possible using conventional data acquisition systems. However, the raw measurements also include the signal noise which may lead to difficulty when the signal is analyzed. This work assesses an algorithm for removing possible signal noise, usually with high-frequency, from the measurement of tracer gas concentration.

The development of new highly sensitive detection techniques for particle bound polycyclic aromatic compounds (PP AH) on the nano-particles of traffic born soot open a new dimension for real time measuring techniques for air exchange rates in buildings in operation. The principles and first measurements are presented and demonstrate the principal applicability of this method.

Air change rates in a cross-ventilation model were measured from the decay curves of video image signals obtained by the step down method assuming perfect mixing of tracer mists inside the spaces. Wind tunnel test results led to the following conclusions. 1) Ray extinction due to lighting scattering did not affect the measurement accuracy of the air change rates in the two-dimensional model. 2) Tracer mists in a diameter between 0.25 μ m and 2.0 μ m produced the same measurement accuracy.