Fluctuating pressure and thermal environments of runway joint seals exposed to jet engine exhaust

Abstract

Jet engine exhaust flow impinging on runway joint seals creates an aerothermoacoustic environment consisting of fluctuating pressure (acoustical and hydrodynamic) and incident gas temperature rapidly increasing with time. Fluctuating pressure at the surface of a joint seal on a runway was measured with microphones and low-pressure transducers positioned along the runway centerline. Temperatures were measured with thermocouples imbedded within the seal and on the surface, along the runway centerline and at several sideline distances. Pressure and temperature data were recorded during aircraft takeoff and landing operations. Measurements indicated incident noise pressure levels of approximately 164 dB re: 20 μPa, surface temperatures over 155 °C, and seal internal temperatures of 100 °C. Fluctuating velocity of the seal was calculated, treating the seal as a fluid flowing between parallel walls. Energy absorption rate was found to equal 850 W/m2, 4.7% of the power available from the incident fluctuating pressure field. Thermal energy through convective heat transfer was absorbed at 34 000 W/m2, 97.5% of total energy absorption.