Thermal analysis of anti-icing systems in aeronautical velocity sensors and structures (original) (raw)
Related papers
2005
The paper deals with a problem of transient temperature measurements performed on the airfoil exposed to icing conditions. Two types of investigations are discussed: in-flight tests and laboratory icing experiments in a wind tunnel. In the first case measurements were performed during test flights of the Polish TS-11 „Iskra” jet plane. A specially designed on board temperature measurement system was utilised to record the temperature changes in five selected points at the wing. Experiments of the second kind were performed on the NACA0012 model airfoil in a small scale icing research tunnel. In this case a multichannel temperature measurement laboratory system was applied. The experiments were focused on the icing phenomena investigations. The obtained results were analysed in view of the supercooled fuel effect on the heat transfer and on temperature distribution. 1.0 INTRODUCTION The aircraft icing phenomena still attain great attention [1], [2]. It is mostly because the aircraft ...
Infrared thermography on testing an anti-icing device
Proceedings of the 1994 International Conference on Quantitative InfraRed Thermography, 1994
An infrared scanning radiometer, applied to the heated thin foil technique, is employed to test the performance of an anti-icing device, which consists of a hot air spray-tube inside aerodynamic surfaces as leading-edge wing sections. Experimental tests are made in order to determine the convective heat transfer coefficients between the surface of the wing section and the air jets impinging on it. The influence of several parameters such as the Mach number, the impingement distance, the diameter of the holes of the spray-tube and the spacing between holes is considered. Nomenclature d hole diameter c wing cord k air thermal conductivity M Mach number Nu Nusselt number Re Reynolds number S hole-to-hole spacing T temperature Z impingement distance x chordwise coordinate y spanwise coordinate
AIRCRAFT WING ANTI-ICING: THERMAL BOUNDARY-LAYER MODELS COMPARISON
Based on a tested electro-thermal anti-ice numerical tool, the present authors propose simplifications in model assumptions to assess their relevance in wing surface temperatures prediction and end of runback water location. The purpose is to demonstrate that momentum and heat analogy and abrupt laminar-turbulent transition approximations may not represent the physical phenomena with the accuracy required. The existent mathematical model considers flow around non-isothermal and transpired airfoil surfaces with a smooth laminar-turbulent transition occurence. Two simplifications are implemented herein: 1) the flow over isothermal surfaces by the use of Colburn analogy; 2) the abrupt laminar-turbulent transition. The boundary layer procedures used in classic icing codes assume similar simplifications and they have limited application in wing electro-thermal anti-ice simulation. The present paper results show that streamwise surface temperature gradient and the occurence of transition, within the protected area, must be considered in mathematical modelling of aircraft thermal ice protection.
Heat transfer in a multi-layered thermal protection system under aerodynamic heating
International Journal of Thermal Sciences, 2012
Future generation reusable re-entry vehicles must be capable of sustaining consistent repeated aerothermal loads without damage or deterioration. This means that such structures should be able to withstand high temperatures engendered by aero-thermal re-entry fluxes due to the establishment of a hypersonic regime over the body.
Transactions of the Canadian Society for Mechanical Engineering, 2013
This article proposes the use of the Box-Behnken design of experiment (DoE) methodology to study an aircraft anti-icing system. The anti-icing system consisted of a piccolo tube with round apertures for producing air jets inside a wing. Mass flow, jet to wall distance, and jet impact angle were varied, starting from an initial design, in order to maximize heat transfer effectiveness. A conjugate heat transfer procedure from commercial CFD software was used to solve for cold air external flow, compressible internal flow, and thermal conduction in the airfoil skin. The DoE methodology was validated using a single impinging jet. A quadratic model of the heat transfer effectiveness of the anti-icing system was then built using the methodology and the maximal value was sought.
Aerothermodynamic study of UHTC-based thermal protection systems
Aerospace Science and Technology, 2005
Computational Fluid Dynamics (CFD) simulations are coupled to a thermal analysis model to investigate the thermal response of the new Ultra High Temperature Ceramics (UHTC) being considered for Thermal Protection Systems (TPS) of future reusable re-entry vehicles. The numerical methodology has been applied to the Sub-orbital Re-entry Test (SRT), mission foreseen in the frame of the Italian unmanned space program. The numerical prediction of the aerodynamic heating of the "sharp" nose of the vehicle has been performed coupling the solution of the external aerodynamic flow field with the thermal field in the TPS; different methodologies have been applied, considering the effects of surface catalysis and laminar-turbulent transition. The results indicate that, for a correct prediction of the aerothermal loads on a UHTC material, coupled time-dependent simulations for both external aerodynamic flow and internal thermal field are essential. The numerical investigations also show that surface catalysis is of negligible importance for a sharp configuration in free flight, but it must be taken into account while performing ground tests in high enthalpy facilities. Furthermore, for the considered "sharp" configuration, laminar-turbulence transition effects are critical for TPS design, since they may increase TPS surface temperature of, at least, 400 K.
Different turbulence models for prediction of enhanced heat transfer of hot-air jet anti-icing systems are analysed with the commercial code Fluent. The heat exchange between a flat plate and a circular jet orthogonally impinging on it was studied for a nozzle-to-plate distance H/D = 6 and for Reynolds number based on jet diameter in the range of 5,000 to 30,000. The numerical results were compared to experimental data found in literature and the RNG k − model with Enhanced Wall Treatment proved to be best turbulence model to predict the plate to jet heat transfer. This model was furthermore validated analysing a 3D linear array of jets orthogonally impinging on a flat plate. As final application, the performance of a wing section (profile RAE 2822) with an anti-icing system with a piccolo tube inserted in a bay occupying the first 7% of the chord was studied. The flow inside the bay was solved, coupled with the flow around the wing section and with the heat convection and conduction on and through the leading edge skin, respectively.
EAE 077 Chapter 11 Temperature and Heat Transfer Measurements
2009
This chapter deals with the state-of-the-art in temperature and heat transfer measurements that are frequently encountered in Aerospace Engineering. Resistive temperature transducers, thermocouples, bi-metallic temperature sensors, semi-conductor diode-based temperature sensing, liquid crystal thermography, infrared thermography, and pyrometry are discussed in detail. Measurements of convective, conductive, radiative, or total heat transfer rates are often required in aerospace engineering such as atmospheric re-entry studies, hot-section component development for gas turbines, ramjet/scramjet development, ballistic missile nose cone development, heat exchanger development, rocket engine combustors, and nozzles. Finally, heat transfer measurements are discussed. Although many illustrations and discussions are used throughout the text, more detailed information in this area can be obtained from the many valuable references provided.