Numerical Analysis Of Icing Parameters Along Shaped Intakes

Ice accretion may occur on the entry components of an aero-engine, such as the struts and the centre conical body under some meteoric and flight conditions. Once the ice becomes thicker and thicker, the mass flow rate of airflow would reduce, that would lead to engine performance deterioration. If the ice accretes severely, the engine couldn't work normally and even endanger the aircraft. In generally, the airflow entering into the engine may pass through an intake, whose cross section is generally non-circular shaped because of the requirement of stealth. Then the icing parameters at the engine entry will be very different from that in the outside atmosphere. In order to understand the variation characteristics of the icing parameters along the intake and their effects on ice accretion on entry parts of aero-engine, a numerical study is conducted in this thesis.With the Euler-Euler method, the two-phase flow and heat transfer of air and super-cooled water droplets along the S-intake, Y-intake and Serpentine-intake at low Mach number under atmospheric icing conditions were numerically simulated. The distribution and variation characteristics of the icing parameters along the intakes and on the outlet were studied.The results are as following:(1) With the increase of Ma, the distortion index of temperature on the outlet of the two dimensional S-intake increases, while the distortion index of liquid water content increases at first and then decreases with a maximum distortion at Ma = 0.2; the liquid water content near the windward wall of the intake channel is relatively larger than that of other regions; the air temperature drop relative to incoming flow at near the entrance of the intake is up to about 17K at Ma = 0.5.(2) The liquid water content is relatively larger in windward wall of the two-dimensional Y-Intake at Ma = 0.3, while that of region where the total pressure is low along the intake is lower. And there is a group of vortex in this region. The air temperature drop at the intake inlet is about 6K to 7K, while the air temperature incensement at the outlet is about 2K to 3K.(3) The liquid water content is relatively larger in windward wall of the two-dimensional Serpentine-intake at Ma = 0.3, while that of near wall region of the upper surface is lower. And there are local regions where the flow is almost stagnant in the upper part of expansion section of the intake.(4) The air temperature in the stagnation region of the centre conical body is relatively higher, which decreases in the downstream and reaches a minimum at the struts root. When Ma = 0.4 the lowest air temperature is 11K lower than that of incoming flow. With the increase of Ma, the area where the concentration of water droplets is relatively higher moves gradually from the left region to the middle region on the outlet and the corresponding area on the centre conical body increases.