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In this paper a cold soak fuel frost modeling for an aircraft wing tank is presented. Numerical prediction is compared with experimental data and a qualitative verification for the frost formation and melting is also shown. The numerical simulation showed good agreement with experimental observations. The model was used to define, through a Monte Carlo analysis, two different frost formations whose impact on aircraft handling was evaluated by flight tests using representative grits.

This paper presents an aerodynamic degradation study of an iced airfoil, using the Lattice Boltzmann approach with the commercial software PowerFLOW. Three-dimensional numerical simulations were performed with an extruded constant section of the GLC-305 airfoil with a leading-edge double-horn ice shape using periodic boundary conditions. The freestream Reynolds number, based on the chord, is 3.5 million and the Mach number is 0.12. An extensive comparison of the main flow features with experimental data is performed, including aerodynamic coefficients, pressure coefficient distributions, velocity and turbulence contours along with its profiles at several positions, and stagnation streamlines. The drag coefficient agrees well with experiments, in spite of a small shift. Two different wind tunnel measurements, using different measurement techniques, were compared to the CFD results, which mostly stayed in between the experimental data.

Today’s airplanes are well equipped to cope with most common icing conditions. However, some atmospheric conditions consisting of supercooled large droplets (SLD) have been identified as cause of severe accidents over the last decades as existing countermeasures even on modern aircraft are not necessarily effective against SLD-ice. In 2014, the new Appendix O to the certification regulations (FAR Part 25 / CS-25) had been issued to guarantee the safe operation of future airplane when encountering SLD conditions. But as the SLD topic is quite new for the majority of aircraft manufacturers and research institutes in a same way, DLR (German Aerospace Center) and Embraer established a joint research cooperation in 2012 to obtain a better understanding of the distinct influences of SLD-ice shapes on aircraft characteristics and to evaluate proper ways for future airplane certification under App. O.

Results from a three-dimensional computer model of a Carbon Nanotubes (CNT) based de-icing system are compared to experimental data obtained at COLLINS-Ohio Icing Wind Tunnel (IWT). The experiments were performed using a prototype of a CNT based de-icing system installed in a section of a business jet horizontal tail. The 3D numerical analysis tools used in the comparisons are AIPAC [1] and CFD++. The former was derived from HASPAC, an anti-icing computer model developed at Wichita State University in 2010 [3, 9, 10]. AIPAC uses the finite volumes method for the solution of the icing problem on an airfoil leading edge (or other 3D surfaces) and relies on any CFD solver to obtain the external flow properties used as boundary conditions. AIPAC is capable of predicting 3D multi-step ice shapes under rime, glaze and mixed regimes, and can also deal with the complex dynamics of cyclic ice accretion, melting, and shedding present in the realm of aircraft electrothermal de-icing systems.

Nowadays, many different research efforts are being conducted to develop personal ventilation system for aircrafts. A numerical CFD study is presented as an example analysis, finding the relationship between the initial jet temperature and mass flow to the local thermal comfort on the head, chest and face. Typical regional airplane cabin geometry was used with two passengers seated. The passengers were modeled with numerical manikins with body and arms. The study first investigated whether the personal ventilation jet has influence on only one of the passengers or if it also affects the other. It was demonstrated that the proposed personal ventilation outlet can influence local thermal comfort with minimum influence on the adjacent passenger. The equivalent temperatures on the head, chest and face were calculated with different initial jet temperatures.

Typical derivative aircraft share nose geometry and air data sensors installations and Static Source Error Correction (SSEC). So, those derivative designs are expected to present similar air data calibration residual errors. Although such results are somehow expected, the certification process requires evidence from flight tests and analyses. During the certification of a derivative model of a regional jet, Computational Fluid Dynamics (CFD) analyses have been conducted in order to evaluate the suitability of such tool for this problem. Both the basic and derivative models are assumed to share: (i) nose geometry; (ii) air data sensors positions and installation and (iii) Static Source Error Correction (SSEC). CFD simulations have been performed for different configurations and flight conditions.