Investigation on the Mechanism of Heat Load Reduction for the Thermal Anti-Icing System

Abstract

The aircraft ice protection system that can guarantee flight safety consumes a part of the energy of the aircraft, which is necessary to be optimized. A study for the mechanism of the heat load reduction in the thermal anti-icing system under the evaporative mode was presented. Based on the relationship between the anti-icing heat load and the heating power distribution, an optimization method involved in the genetic algorithm was adopted to optimize the anti-icing heat load and obtain the optimal heating power distribution. An experiment carried out in an icing wind tunnel was conducted to validate the optimized results. The mechanism of the anti-icing heat load reduction was revealed by analyzing the influences of the key factors, such as the heating range, the surface temperature and the convective heat transfer coefficient. The results show that the reduction in the anti-icing heat load is actually the decrease in the convective heat load. In the evaporative mode, decreasing the heating range outside the water droplet impinging limit can reduce the convective heat load. Evaporating the runback water in the high-temperature region can lead to the less convective heat load. For the airfoil, the heating power distribution that has an opposite trend with the convective heat transfer coefficient can reduce the convective heat load. Thus, the optimal heating power distribution has such a trend that is low at the leading edge, high at the water droplet impinging limit and zero at the end of the protected area.

Numerical Investigation of the Aerofoil Aerodynamics with Surface Heating for Anti-Icing

“…In this section, instead of heating the entire aerofoil surface, heat flux is only provided in a limited region with a constant temperature to figure out its influence on the aerofoil aerodynamic performance. The previous experimental study has shown that the LE of the aerofoil is the most vulnerable position to icing and the ice accretion gradually reduces along the chord to TE [8]. The heating area in this study is denoted by the percentage of the blade chord starting from the LE.…”

“…Therefore, the heating area of the upper surface is limited to 40%. Regarding the lower surface, Figure 12 shows that the near-wall temperature of the lower surface is higher than the upper surface even without heating, and there is generally no ice accumulation in the region downstream of 30% chord [8]. Consequently, heating is only applied in the first 30% chord area on the lower surface.…”

“…Consequently, heating is only applied in the first 30% chord area on the lower surface. Regarding the heating temperature, it can be set just higher than the icing temperature to achieve an anti-icing effect [8]. The highest temperature of icing is −10 ∼ 0 • C [15,16] above which no ice can be accreted.…”

“…The fuel consumption is therefore increased [6] which makes it essential to optimise the energy consumption on duty. Efforts have been devoted into the performance improvement and heat load optimisation of the thermal anti-icing system [7,8]. It is proposed that reducing the heating intensity of non-critical areas can save energy and alleviate the adverse influence on aerodynamic performances [9].…”

Boundary protection based on the anti-icing thermal load surrogated model and the WRF icing meteorological prediction

“…Ni et al (2021) investigated the influence of the velocity, height, LWC, temperature and MVD on the anti-icing thermal load. Li et al (2020) studied the mechanism of the anti-icing thermal load reduction under the full evaporative mode and optimized the heating power distribution. Bu et al (2013) predicted the anti-icing thermal load with the proper orthogonal decomposition (POD).…”