Pressure Drop Characteristics of Water Flow Through Static Annular and Triangular Cavity Labyrinth Seals

Abstract

Non-contacting static seals are intended to provide high pressure drop at different leakage flow rates for better sealing. In special applications such as cryogenic engines and nuclear reactors which have high sealing requirements, conventional annular seals and circular-grooved square cavity labyrinth seals often do not meet the demand. This paper investigates newer configurations like circular-grooved triangular cavity labyrinth seals and sinusoidal-grooved triangular cavity labyrinth seals which can provide improved sealing than conventional seals. For these seals, pressure drop data over a wide range of water flow rates has been obtained using computational simulations and experiments. The pressure drops for the triangular seals are observed to be marginally more than those for square labyrinth seals and markedly higher than those for annular seals. The numerical results are also in good agreement with experimental and available analytical results. In order to highlight the effects of cavity shape and seal configuration, optimisation of a circular-grooved triangular labyrinth seal has been carried out using Artificial Neural Network (ANN), in association with a semi-theoretical model. The pressure drop for the identified optimal triangular labyrinth seal is 16% higher than that of the optimal square labyrinth seal. Among the seals tested, the sinusoidal-grooved triangular labyrinth seal exhibits the highest pressure drop, exceeding that of the optimal circular-grooved triangular labyrinth seal by 57%, at the rated flow rate.