CFD improves design in six days

Problem: . Often, the engineer has to find the best design from two slightly different options. The problem is, how does he or she avoid having to go through a lengthy and perhaps hit-and-miss programme of design, testing and re-design? Solution: Computational fluid dynamics (CFD) is one very useful method of solving such problems. CFD software specialist Advantage CFD, based in Brackley, recently carried out an analysis of a cyclone separator that was being designed by a long-established vacuum cleaner manufacturer. The firm's task was to investigate the difference in dust flow patterns and particle behaviour between two sizes of dust-sucking inlet - one at 500mm2 and the other at 800mm2 - at a constant flow rate of 30 litres per second and then recommend the which design would give the best performance for the power available to it. The analysis, which did not require building or testing prototypes, took just six days and resulted in a mass of useful data, including the identification of an unsuspected design problem. One of the key conclusions was that the 500mm2 inlet had a higher inlet velocity and was better at separating dust particles from the air flow. There was, however, a penalty. Reducing the cross-sectional area of the inlet pipe meant that more power was needed to drive the flow through the system. The CFD model predicted a 0.155kW increase in power required for the 500mm2 inlet compared to the 800mm2 inlet. The surprise came from the CFD simulations which suggested that the separator was the wrong shape and that improving it would probably result in even better separation of dust from the air flow. Applications: CFD software can be used to predict or simulate almost any engineering design application. The performance of a specific component or assembly can be carried out quickly and different design iterations checked and compared against each other to optimise the final design. DP