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Various nose cowl internal geometry designs have been investigated in a study relating to the effect of hot air mass flows in the prevention of ice formation on the external nose cowl (lipskin) surfaces of aero-engine intakes. Significant differences in the lipskin surface temperature levels were observed as the internal, hot, anti-icing air distribution geometry was altered. A double-skinned arrangement (in which the hot air was closely confined to the region requiring protection against ice formation) was observed to be particularly advantageous in this respect. The effectiveness of this design was matched however by a conventional “piccolo” pipe distribution system whilst the remaining two internal Builds investigated were found to be not as effective. In evaluating the benefits that accrue from a particular design, factors such as weight, cost, reliability, maintenance and in-service experience must also be considered.

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• This is an article from the journal, Proceedings of the IMechE, Part D: Abstract: An existing quasi-dimensional engine cycle model has been modified to enable accurate prediction of the near-wall temperature field in the burned and unburned gases. This has been achieved by dividing the cylinder into a number of discrete masses, each of which has a unique state. These discrete masses are assumed to remain stacked in layers adjacent to the cylinder walls in both the unburned gas and in the discrete segments generated during the sequential burning process. A kÀå turbulence model has been incorporated into the engine cycle simulation, providing information on the nature of the instantaneous in-cylinder turbulence for input to a fractal flame model to depict the flame propagation process. When this approach is applied to the prediction of the flame propagation rate, excellent comparison is afforded between simulated and measured pressure±crank angle diagrams. Further validation is provided by comparison of near-wall temperature predictions with measured ones and the essential features of the observed boundary layer behaviour are reproduced.