Browsing by Author "Pervier, Hugo"

Now showing 1 - 14 of 14
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    Computational approach for investigating nanoscale interfacial ice adhesion trends
    (Royal Society of Chemistry, 2023-12-12) Vincent, Abhay; Pervier, Marie; Pervier, Hugo; Nalianda, Devaiah
    For developing high performance, low-energy ice protection systems, it is vital to understand the icing physics at the interface of the ice and substrate. Macroscopic experiments have known limitations when it comes to explaining the adhesion characteristics of ice. There is a need to look at the microscale behaviour of ice and how it interacts with the surface it adheres on. The article describes application of molecular dynamics to the ice-substrate problem by modelling two major modes of ice adhesion test – tensile and shear tests, which are used for ice adhesion strength determination. The coarse-grained model of water is nucleated to form ice at the temperature which is designated for ice adhesion test on a macroscopic level. Steered molecular dynamics (SMD) is then applied to the nucleated ice cube to then obtain tensile and shear adhesion strengths over various FCC surface morphologies that represent the crystal structure of metallic substrates. The results obtained from the adhesion simulations are then used to compare the nanoscale trends on ice adhesion to the macroscale ice adhesion trends. The simulation results show that while contact area and temperature variations have similar trends to the observed macroscopic trends, other variations like tensile and shear loading rate variation at the nanoscale are not directly understood from macroscopic interpretations of ice adhesion.
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    Design, construction and commissioning of the Braunschweig Icing Wind Tunnel
    (European Geosciences Union (EGU), 2018-06-06) Bansmer, Stephan E.; Baumert, Arne; Sattler, Stephan; Knop, Inken; Leroy, Delphine; Schwarzenboeck, Alfons; Jurkat-Witschas, Tina; Voigt, Christiane; Pervier, Hugo; Esposito, Biagio
    Beyond its physical importance in both fundamental and climate research, atmospheric icing is considered as a severe operational condition in many engineering applications like aviation, electrical power transmission and wind-energy production. To reproduce such icing conditions in a laboratory environment, icing wind tunnels are frequently used. In this paper, a comprehensive overview on the design, construction and commissioning of the Braunschweig Icing Wind Tunnel is given. The tunnel features a test section of 0.5 m  ×  0.5 m with peak velocities of up to 40 m s−1. The static air temperature ranges from −25 to +30 °C. Supercooled droplet icing with liquid water contents up to 3 g m−3 can be reproduced. The unique aspect of this facility is the combination of an icing tunnel with a cloud chamber system for making ice particles. These ice particles are more realistic in shape and density than those usually used for mixed phase and ice crystal icing experiments. Ice water contents up to 20 g m−3 can be generated. We further show how current state-of-the-art measurement techniques for particle sizing are performed on ice particles. The data are compared to those of in-flight measurements in mesoscale convective cloud systems in tropical regions. Finally, some applications of the icing wind tunnel are presented.
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    The effect of accretion temperature on microstructure and bending strength of atmospheric ice
    (Elsevier, 2023-11-02) Fallon, C.; Truyen, E.; Eakins, D.; Pervier, Hugo; Pervier, Marie L. A.; Aceves Lopez, M.
    Accurate determination of the mechanical response of atmospheric ice is key to understanding the risks associated with ice impact on aircraft during flight. Two types of atmospheric ice which are of particular interest to the aerospace industry are studied. Rime and Glaze ice are each manufactured in an icing wind tunnel facility under controlled conditions. Rime ice is accreted at a temperature of −20◦C, and Glaze ice is accreted at −5 ◦C. Quasi-static threepoint bend tests are performed on both types of ice to understand the effect of accretion temperature, and therefore microstructure, on strength. The results indicate that the ice accretion temperature, and thus microstructure, has a significant influence on the bending strength. On average, the bending strength of Rime ice is 9.0 ± 0.18 MPa compared to 4.4 ± 0.093 MPa for Glaze. The comparatively lower accretion temperature of Rime results in smaller grain sizes and higher bending strength. In contrast, the effective modulus appears insensitive to ice microstructure, with an average value of 3.5±0.12 GPa for Rime compared to 3.6±0.098 GPa for Glaze. Furthermore, the results indicate that both the bending strength and effective modulus are insensitive to the ice storage time.
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    Emissions modelling for engine cycle and aircraft trajectory optimisation
    (Cranfield University, 2013-06) Pervier, Hugo; Sethi, Vishal
    The aviation industry is currently experiencing a growth rate of about 4% per annum and this trend is expected to continue into the future. One concern about this growth rate is the impact it will have on the environment particularly in terms of emissions of CO2, NOx and relatively recently also cirrus clouds induced by contrails. The ACARE has set emissions reduction targets of 50% reduction of CO2 and noise and 80% reduction of NOx by 2020 relative to Y2000 technology. Clean Sky and other large EU collaborative projects have been launched in an effort to identify new, more efficient, aircraft and engine technologies, greener operational and asset management practices and lower life cycle emissions. This PhD research was funded by and contributed to the Systems for Green Operations Integrated Technology Demonstrator (SGO-ITD) of the Clean Sky project. The key contribution to knowledge of this research is the development and application of a methodology for simultaneous optimisation of aircraft trajectories and engine cycles. Previous studies on aircraft trajectory optimisation studies, published in the public domain, are based on relatively low fidelity models. The case studies presented in this thesis are multi-objective and based on higher fidelity, verified aircraft, engine and emissions models and also include assessments of conceptual engines with conceptual LPP combustors. The first task involved the development of reactor based NOx emission prediction models for a conventional aero gas turbine combustor and a novel conceptual lean pre-mixed pre-vaporised combustor. A persistent contrails prediction model was also developed. A multi-disciplinary framework comprising a genetic algorithm based optimiser integrated with an engine performance, an aircraft performance and an emission prediction model was then developed. The framework was initially used to perform multi-disciplinary aircraft trajectory optimisation studies and subsequently both aircraft trajectory and engine cycle optimisation studies simultaneously to assess trade-offs between mission fuel burn, flight time, NOx production and persistent contrails formation ... [cont.].
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    Experimental characterization of anti-icing system and accretion of re-emitted droplets on turbojet engine blades
    (AIAA, 2018-06-30) Linassier, Guillaume; Balland, Morgan; Pervier, Hugo; Pervier, Marie L. A.; Hammond, David; Radenac, Emmanuel
    In the framework of STORM, a European project dedicated to icing physics in aircraft engines, a cascade rig representative of an anti-iced engine inlet was tested in icing conditions. This mock-up integrates two rows of vanes, the upstream one being anti-iced using an Electro-Thermal Ice Protection System (ET-IPS). Experimental tests were performed to reproduce the following phenomena: runback water and droplet re-emission from anti-iced vanes, and accretion of re-emitted droplets on downstream vanes. A complete experimental database was generated, including the characterization of ice accretion shapes, and the characterization of electro-thermal anti-icing system (power limit for apparition of the runback water or ice accretion). In the current study, these data are compared to droplet trajectory simulation and ice accretion simulation results, for validating icing tools in engine environment. Influence of one-step and multi-step approaches have been investigated.
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    Experimental rig for ice accretion and adhesion strength measurement for air cycle machine system
    (Elsevier, 2023-06-06) Vincent, Abhay; Pervier, Marie L. A.; Pervier, Hugo; Nalianda, Devaiah; West, Peter; Agustin-Saenz, C.; Brusciotti, F.
    Air cycle machines (ACM) which are part of the air-conditioning pack in every aircraft, are one such turbomachinery device that can be affected by icing issues particularly at the turbine end. Current ice protection solutions for the air cycle machines use a heating system on the downstream pipe to heat the surface, using electric resistance heaters or hot air coming from the ACM compressor stage. Both solutions require high energy, hence the need to reduce energy consumption through the development of passive energy-saving solutions. Clean Sky 2 ERICE project aims at developing an eco-friendly and cost-effective hydrophobic / ice-phobic solution able to resist ice adhesion in the ACM turbine scroll and its downstream pipe. This paper discusses the implementation of an experimental rig to reproduce the ice formation and accretion conditions within the ACM and a new shear test method to measure the ice adhesion strength on existing and new solutions in the form of coatings. The flow through the ACM turbine exhaust has also been characterized for the first time in published literature. The results from the ice accretion and adhesion tests show that hydrophobic coatings developed for the purposes of ice protection perform better than the current industry baseline material for ACM turbine scroll pipe internal surface. While these coatings could not be used to prevent accretion, they do help in reducing adhesion of ice to the surface.
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    High Speed Camera Tests - ERICE
    (Cranfield University, 2023-06-06 14:25) Vincent, Abhay; Pervier, Marie; Pervier, Hugo
    This item contains the data from the High speed camera tests for ERICE project based on conditions 1 and 2 of the test matrix. Data includes: 1) High Speed camera videos for two test conditions (x2) - '.avi' format 2) Labview files (x2) - '.lvm' format (read with MS Excel) 3) README txt file (x1) - explaining the headers for the labview data and the instrumentation involved. Test 1 refers to the 50k RPM condition from the test matrix and Test 2 refers to the 60k RPM condition from the test matrix.
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    Malvern Tests - ERICE
    (Cranfield University, 2023-06-06 14:25) Vincent, Abhay; Pervier, Marie; Pervier, Hugo
    This item contains the data from the tests done for characterization of flow using Malvern Particle Analyzer for the ERICE project. Data includes: 1) Labview files (x2) - '.lvm' format (to be read with MS Excel), 2) Excel sheet with data post-processing (x2) - '.xlsx' format (to be read with MS Excel), 3) Test run video files (x2) - '.mkv' files, 4) README txt file (x1) - explaining the headers for the labview data and the instrumentation involved. Test 1 refers to the test run at 60k RPM & Test 2 refers to the test run at 50k RPM
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    Observation of microstructures of atmospheric ice using a new replica technique
    (Elsevier, 2017-05-13) Pervier, Marie-Laure; Pervier, Hugo; Hammond, David
    A replication technique has been developed to study the microstructure of atmospheric ice based on the use of nail varnish rather than more harmful materials. The potential of the technique was demonstrated by obtaining and reporting microstructures for impact ice grown on metal surfaces in an icing tunnel under a range of cloud conditions. The technique reveals grain structure, growth striations, porosity and etch features which may indicate an aspect of crystallographic orientations.
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    Photoacoustic hygrometer for icing wind tunnel water content measurement: design, analysis and intercomparison
    (European Geosciences Union, 2021-03-31) Lang, Benjamin; Breitfuss, Wolfgang; Schweighart, Simon; Breitegger, Philipp; Pervier, Hugo; Tramposch, Andreas; Klug, Andreas; Hassler, Wolfgang; Bergmann, Alexander
    This work describes the latest design, calibration and application of a near-infrared laser diode-based photoacoustic (PA) hygrometer developed for total water content measurement in simulated atmospheric freezing precipitation and high ice water content conditions with relevance in fundamental icing research, aviation testing, and certification. The single-wavelength and single-pass PA absorption cell is calibrated for molar water vapor fractions with a two-pressure humidity generator integrated into the instrument. Laboratory calibration showed an estimated measurement accuracy better than 3.3 % in the water vapor mole fraction range of 510–12 360 ppm (5 % from 250–21 200 ppm) with a theoretical limit of detection (3σ) of 3.2 ppm. The hygrometer is examined in combination with a basic isokinetic evaporator probe (IKP) and sampling system designed for icing wind tunnel applications, for which a general description of total condensed water content (CWC) measurements and uncertainties are presented. Despite the current limitation of the IKP to a hydrometeor mass flux below 90 gm-2s, a CWC measurement accuracy better than 20 % is achieved by the instrument above a CWC of 0.14 g m−3 in cold air (−30 ∘C) with suitable background humidity measurement. Results of a comparison to the Cranfield University IKP instrument in freezing drizzle and rain show a CWC agreement of the two instruments within 20 %, which demonstrates the potential of PA hygrometers for water content measurement in atmospheric icing conditions
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    README [Test Matrix & Description - ERICE]
    (Cranfield University, 2023-06-06 14:25) Vincent, Abhay; Pervier, Marie; Pervier, Hugo
    The item consists of a presentation ('pptx' format) which describes the two distinct test matrix conditions for the ERICE tests and a text file which describes the process of all the various tests performed within this research work. These conditions were used for all the testing done within the ERICE project.
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    Test Matrix Condition 1 Tests - ERICE
    (Cranfield University, 2023-06-06 14:26) Vincent, Abhay; Pervier, Marie; Pervier, Hugo
    This item contains the condition 1 tests conducted under ERICE. These tests were done at 60k RPM of the turbocharger and were only to observe the ice accretion and no scrape tests were performed for tests in these conditions. The item includes the following data: 1) Labview files (x8) - '.lvm' format (read with MS Excel) 2) Video files (x8) - '.mkv' format 3) README txt file (x1) - explaining the headers for the labview data and the instrumentation involved - Test 1 refers to Wearlon sample; Test 2 refers to AA Fsmooth sample; Test 3 refers to Al sample; Test 4 refers to AA F75 sample; Test 5 refers to Thin SAA + TCS sample; Test 6 refers to Thin SAA + PTFE; Test 7 refers to Xylan sample; Test 8 refers to WSAA Fsmooth sample
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    Test Matrix Condition 2 Tests - ERICE (Scrape Test Data)
    (Cranfield University, 2023-06-06 14:26) Vincent, Abhay; Pervier, Marie; Pervier, Hugo
    This item contains the details of the 40 total successful test runs for the Condition 2 of the ERICE test matrix. Ice was accreted using this condition and then tested in the Scrape Test setup to obtain adhesion test values for 8 samples. The item consists of the following data types: 1) Labview files for rig sensors (x39) - ".lvm" format - to be read using Excel, 4th test for Xylan had no file due to recording error 2) Labview files for scrapetest (x41) -.lvm format" - to be read using MS Excel 4th test for Xylan had no file due to recording error extra test for AA Fsmooth 5th test 3) Video files (x39) - ".mkv" format 4) Color-coded test matrix (x1) - ".xlsx" format - to be read using MS Excel 5) README txt file (x1) - explaining the headers for the labview data and the instrumentation involved. Each sample apart from AA Fsmooth has 5 tests completed and are labelled in that order. AA Fsmooth has an extra test and hence the scrapetest files are labelled as 5a and 5b."
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    Trace-wire Tests - ERICE
    (Cranfield University, 2023-06-06 14:25) Vincent, Abhay; Pervier, Marie; Pervier, Hugo
    This item contains the data from the trace-wire testing performed for the ERICE project. The following files are present within this item: 1) Labview files (x3) - ".lvm" format (to be read in MS Excel) 2) Video files (x3) - ".mkv" format 3) README txt file (x1) - explaining the headers for the labview data and the instrumentation involved. Test 1 refers to Aluminium sample Test 2 refers to Wearlon sample Test 3 refers to AA Fsmooth sample