Computational fluid dynamics as a method for assessing fume cupboard performance

A commercially available computational fluid dynamic (CFD) software program , specific for HVAC systems, was used to study the performance of an aerody namic fume cupboard. The numerical results showed good qualitative agreemen t with physical measurements giving confidence in the CFD model to simulate and predict overall fume cupboard performance. However, there were some qu antitative differences specifically around 'aerodynamic' features that coul d not be accurately simulated by the software code. The CFD model,vas clear ly able to demonstrate differences in performance between good and bad cupb oard designs, and show the importance of using rear baffles and lipfoils, I t also showed the importance of good design features when a 'worker' was st anding against the front edge or when there were draughts in front of the a perture. The computer model was used to simulate the gas tracer containment test method described in BS 7258 (1994) [Laboratory Fume Cupboards], and h ad a much greater sensitivity than the recommended physical measuring instr uments. The results given in this paper demonstrate the potential for using a commercially available software package for the optimisation of fume cup board design and testing, It also indicates the economy of using CFD compar ed with building a prototype and testing a model. (C) 2000 British Occupati onal Hygiene Society. Published by Elsevier Science Ltd. All rights reserve d.