Optimization of air curtain technology through temporal or spatial jet excitation

Air curtains are of strategic importance in the built environment to reduce the negative impacts that air infiltration can pose to the energy performance, air quality and thermal comfort of buildings that have entrance doors with high-usage frequency. Furthermore, due to the unique flow and transport characteristics of the air-curtain technology, this can be an attractive technology in multiple industrial sectors for purposes such as fire safety, refrigeration, dust restriction and air pollution control.
In view of the potential influence that jet and environmental parameters can have on the key performance parameter of air curtains—their separation efficiency—, this thesis report addresses the current lack of knowledge on the topic and aims to provide a deeper understanding on the effect of these parameters on the air-curtain separation efficiency. Moreover, motivated by the needs in industry to incorporate high-performance air curtains in their processes, this thesis comprises a technological design optimization of the existent air-curtain technology focusing on the implementation of innovative strategies for controlling the vortex dynamics and jet behavior of air curtains by means of temporal and spatial jet excitation techniques.
In pursuance to the objectives of this study, numerical simulations using computational fluid dynamics (CFD) were conducted to make quantitative predictions of the flow behavior in an air-curtain system under different operational conditions, and to perform a parametric evaluation and optimization of the air-curtain separation efficiency with the implementation of jet excitation techniques. The numerical simulations were extensively verified and validated beforehand with dedicated experimental data, thus maintaining high-quality of the simulation results.
The implementation of spatially excited jets as a design optimization strategy can result in tangible improvements to the performance of air curtains and—in its most practical form—could entail only marginal increments in the cost of materials and virtually no increase in the labor costs during manufacturing process of air curtains. Moreover, the proposed strategy implies passive and relatively non-intrusive modifications to the inner construction of existent air curtains, thus suggesting only modest impacts to the current manufacturing, installation and operation processes of the device. Therefore, this is considered to be a feasible technological design solution.