ORCID Profile
0000-0002-7516-1701
Current Organisation
University of Oxford
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 07-2023
Publisher: American Institute of Aeronautics and Astronautics
Date: 05-01-2017
DOI: 10.2514/6.2017-0443
Publisher: Elsevier BV
Date: 04-2011
Publisher: ACM
Date: 21-03-2011
Publisher: Elsevier BV
Date: 06-2011
Publisher: MDPI AG
Date: 22-11-2022
DOI: 10.3390/EN15238813
Abstract: Recent evidence available in the literature has highlighted that the high-energy consumption rate associated with air conditioning leads to the undesired “overcooling” condition in arid-climate regions. To this end, this study quantified the effects of increasing the cooling setpoint temperature on reducing energy consumption and CO2 emissions to mitigate overcooling. DesignBuilder software was used to simulate the performance of a generic building operating under the currently adopted ASHRAE HVAC criteria. It was found that increasing the cooling setpoint temperature by 1 °C will increase the operative temperature by approximately 0.25 °C and reduce the annual cooling electricity consumption required for each 1 m2 of an occupied area by approximately 8 kWh/year. This accounts for a reduction of 8% in cooling energy consumption compared to the ASHRAE cooling setpoint (i.e., t_s = 26 °C) and a reduction in the annual CO2 emission rate to roughly 4.8 kg/m2 °C. The largest reduction in cooling energy consumption and CO2 emissions was found to occur in October, with reduced rates of approximately–1.3 kWh/m2 °C and −0.8 kg/m2 °C, respectively.
Publisher: Elsevier BV
Date: 09-2022
Publisher: Springer International Publishing
Date: 2019
Publisher: AIP Publishing
Date: 2019
DOI: 10.1063/1.5119600
Publisher: AIP Publishing
Date: 2019
DOI: 10.1063/1.5119611
Publisher: Optica Publishing Group
Date: 02-02-2023
DOI: 10.1364/OE.482477
Abstract: Laser-induced grating spectroscopy (LIGS) is an optical diagnostic technique for gas-phase thermometry in challenging environments where physical probes are undesirable. The Portable In-line LIGS for Optical Thermometry (PILOT) instrument is a novel self-contained, compact device capable of tracer-free LIGS measurements at 400 Hz. It can be mounted in any orientation and includes internal alignment capability, adjustable path length matching for the pump beams, and an energy ower attenuation mechanism for the pump robe beams. Characterization of the instrument demonstrated that it can produce accurate ( .37% in ambient air) and precise (±0.7% in ambient air) spatially- and temporally-resolved temperature measurements, and is now ready to be deployed in research facilities.
Publisher: Elsevier BV
Date: 03-2017
Publisher: Cambridge University Press (CUP)
Date: 02-10-2019
DOI: 10.1017/JFM.2019.692
Abstract: A comprehensive study of the fundamental characteristics of leading-edge separation in rarefied hypersonic flows is undertaken and its salient features are elucidated. Separation of a boundary layer undergoing strong expansion is typical in many practical hypersonic applications such as base flows of re-entry vehicles and flows over deflected control surfaces. Boundary layer growth under such conditions is influenced by effects of rarefaction and thermal non-equilibrium, thereby differing significantly from the conventional no-slip Blasius type. A leading-edge separation configuration presents a fundamental case for studying the characteristics of such a flow separation but with minimal influence from a pre-existing boundary layer. In this work, direct simulation Monte Carlo computations have been performed to investigate flow separation and reattachment in a low-density hypersonic flow over such a configuration. Distinct features of leading-edge flow, limited boundary layer growth, separation, shear layer, flow structure in the recirculation region and reattachment are all explained in detail. The fully numerical shear layer profile after separation is compared against a semi-theoretical profile, which is obtained using the numerical separation profile as the initial condition on existing theoretical concepts of shear layer analysis based on continuum flow separation. Experimental studies have been carried out to determine the surface heat flux using thin-film gauges and computations showed good agreement with the experimental data. Flow visualisation experiments using the non-intrusive planar laser-induced fluorescence technique have been performed to image the fluorescence of nitric oxide, from which velocity and rotational temperature distributions of the separated flow region are determined.
Publisher: ACM
Date: 24-10-2011
Publisher: MDPI AG
Date: 24-07-2023
DOI: 10.3390/EN16145583
Abstract: To promote the adoption of Direct Air Capture (DAC) systems, this paper proposes and tests a photovoltaic-powered DAC system in a generic residential building located in Qatar. The proposed DAC system can efficiently reduce CO2 concentration in a living space, thus providing an incentive to in iduals to adopt it. The ventilation performance of the building is determined using Computational Fluid Dynamics (CFD) simulations, undertaken with ANSYS-CFD. The CFD model was validated using microclimate-air quality dataloggers. The simulated velocity was 1.4 m/s and the measured velocity was 1.35 m/s, which corresponds to a 3.5% error. The system decarbonizes air supplied to the building by natural ventilation or ventilation according to the ASHRAE standards. Furthermore, the performance of the photovoltaic system is analyzed using the ENERGYPLUS package of the Design Builder software. We assume that 75% of CO2 is captured. In addition, a preliminary characterization of the overall system’s performance is determined. It is determined that the amount of CO2 captured by the system is 0.112 tones/year per square meter of solar panel area. A solar panel area of 19 m2 is required to decarbonize the building with natural ventilation, and 27 m2 is required in the case of ventilation according to the ASHRAE standard.
Publisher: Optica Publishing Group
Date: 11-04-2023
DOI: 10.1364/AO.472996
Abstract: This paper demonstrates the application of polarized-depolarized Rayleigh scattering (PDRS) as a simultaneous mixture fraction and temperature diagnostic for non-reacting gaseous mixtures. Previous implementations of this technique have been beneficial when used for combustion and reacting flow applications. This work sought to extend its applicability to non-isothermal mixing of different gases. The use of PDRS shows promise in a range of applications outside combustion, such as in aerodynamic cooling technologies and turbulent heat transfer studies. The general procedure and requirements for applying this diagnostic are elaborated using a proof-of-concept experiment involving gas jet mixing. A numerical sensitivity analysis is then presented, providing insight into the applicability of this technique using different gas combinations and the likely measurement uncertainty. This work demonstrates that appreciable signal-to-noise ratios can be obtained from this diagnostic in gaseous mixtures, yielding simultaneous temperature and mixture fraction visualization, even for an optically non-optimal selection of mixing species.
Publisher: Springer Berlin Heidelberg
Date: 2011
Publisher: AIP Publishing
Date: 03-2020
DOI: 10.1063/5.0004266
Abstract: Two-dimensional mapping of the velocity distribution for a hypersonic leading-edge separation flowfield generated by a “tick” shaped geometry is presented for the first time. Discrete measurements of two velocity components were acquired at a flow condition having a total specific enthalpy of 3.8 MJ/kg by imaging nitric oxide fluorescence over numerous runs of the hypersonic tunnel at the Australian Defence Force Academy (T-ADFA). The measured freestream velocity distribution exhibited some non-uniformity, which is hypothesized to originate from images acquired using a set of ultraviolet specific mirrors mounted on the shock tunnel deflecting under load during a run of the facility, slightly changing the laser sheet orientation. The flow separation point was measured to occur at 1.4 ± 0.2 mm from the model leading edge, based on the origin of the free shear layer emanating from the expansion surface. Reattachment of this free shear layer on the compression surface occurred at 59.0 ± 0.2 mm from the model vertex. Recirculating the flow bound by the separation and reattachment points contained supersonic reverse flow and areas of subsonic flow aligned with the location of three identified counter-rotating vortices. A comparison of the recirculation flow streamline plots with those computed using Navier–Stokes and direct simulation Monte Carlo (DSMC) codes showed differences in flow structures. At a flow time close to that produced by the facility, flow structures generated by the DSMC solution were seen to agree more favorably with the experiment than those generated by the Navier–Stokes solver due to its ability to better characterize separation by modeling the strong viscous interactions and rarefaction at the leading edge. The primary reason for this is that the no-slip condition used in the Navier–Stokes solution predicts a closer separation point to the leading edge and structures when compared to the DSMC solution, which affects surface shear stress and heat flux, leading to a difference in flow structures downstream of the separation.
Publisher: IEEE
Date: 09-2011
DOI: 10.1109/HPCC.2011.46
Publisher: Author(s)
Date: 2016
DOI: 10.1063/1.4967573
Publisher: Springer Berlin Heidelberg
Date: 2011
Publisher: Optica Publishing Group
Date: 17-05-2021
DOI: 10.1364/AO.419973
Abstract: Optical diagnostics of gas-phase pressure are relatively unusual. In this work, we demonstrate a novel, rapid, and robust method to use laser-induced grating scattering (LIGS) to derive this property in real time. Previous pressure measurements with LIGS have employed a signal fitting method, but this is relatively time-consuming and requires specialist understanding. In this paper, we directly measure a decay lifetime from a LIGS signal and then employ a calibration surface constructed using a physics-based model to convert this value to pressure. This method was applied to an optically accessible single-cylinder internal combustion engine, yielding an accuracy of better than 10% at all tested conditions above atmospheric pressure. This new approach complements the existing strength of LIGS in precisely and accurately deriving temperature with a simple analysis method, by adding pressure information with a similarly simple method.
Publisher: American Institute of Aeronautics and Astronautics (AIAA)
Date: 04-2023
DOI: 10.2514/1.T6610
Abstract: This paper presents a novel experimental technique where infrared thermography is employed to directly measure the surface heat transfer of a transpiration-cooled porous material in transient hypersonic flow. Experiments were conducted in the Oxford High Density Tunnel on a flat-faced hemispherical probe at a single Mach 7 freestream condition ([Formula: see text]) with nitrogen, air, argon, krypton, and helium injection gases and mass flow rates ranging from 0.01 to [Formula: see text]. Surface heat transfer measurements were extracted by imaging directly on the porous material using a FLIR A6751 high-speed long-wave infrared camera. Porous alumina was chosen due to its favorable thermal properties for infrared analysis and its very small pore sizes ([Formula: see text]) enabling a uniform outflow. It was found that the surface Stanton number reduction matched to within 10% of both computational fluid dynamics results and correlations.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Laurent Le Page.