IOP PUBLISHING MEASUREMENT SCIENCE AND TECHNOLOGY Meas. Sci. Technol. 21 (2010) 025903 (10pp) doi:10.1088/0957-0233/21/2/025903 A new method for simultaneous measurement of convective and radiative heat flux in car underhood applications M Khaled 1,2 , B Garnier 1 , F Harambat 2 and H Peerhossaini 1, 3 1 Thermofluids, Complex Flows and Energy Research Group—Laboratoire de Thermocin´ etique, CNRS-UMR 6607, Ecole polytechnique—Universit´ e de Nantes, rue C Pauc, BP 50609, 44306 Nantes cedex 3, France 2 PSA Peugeot Citro¨ en—V´ elizy A Center, 2 route de Gisy, 78 943 V´ elizy Villacoublay, France E-mail: Hassan.peerhossaini@univ-nantes.fr Received 4 September 2009, in final form 30 November 2009 Published 6 January 2010 Online at stacks.iop.org/MST/21/025903 Abstract A new experimental technique is presented that allows simultaneous measurement of convective and radiative heat flux in the underhood. The goal is to devise an easily implemented and accurate experimental method for application in the vehicle underhood compartment. The new method is based on a technique for heat-flux measurement developed by the authors (Heat flow (flux) sensors for measurement of convection, conduction and radiation heat flow 27036-2, © Rhopoint Components Ltd, Hurst Green, Oxted, RH8 9AX, UK) that uses several thermocouples in the thickness of a thermal resistive layer (foil heat-flux sensor). The method proposed here uses a pair of these thermocouples with different radiative properties. Measurements validating this novel technique are carried out on a flat plate with a prescribed constant temperature in both natural- and forced-convection flow regimes. The test flat plate is instrumented by this new technique, and also with a different technique that is intrusive but very accurate, used as reference here (Bardon J P and Jarny Y 1994 Proc´ ed´ e et dispositif de mesure transitoire de temp´ erature et flux surfacique Brevet n ◦ 94.011996, 22 February). Discrepancies between the measurements by the two techniques are less than 10% for both convective and radiative heat flux. Error identification and sensitivity analysis of the new method are also presented. Keywords: heat-flux measurement, heat-flux separation, convective and radiative heat flux, fluxmeter, foil heat-flux sensor, car underhood compartment, aerothermal management, experimental methods (Some figures in this article are in colour only in the electronic version) Nomenclature A constant e thickness (m) f view factor h heat-transfer coefficient (W m −2 K −1 ) K coefficient n number of thermocouples R thermal resistance (K m 2 W −1 ) 3 Author to whom any correspondence should be addressed. T temperature ( ◦ C) U voltage (V) Subscripts and superscripts 1 fluxmeter 1 2 fluxmeter 2 a air ad adhesive c convective cor correction 0957-0233/10/025903+10$30.00 1 © 2010 IOP Publishing Ltd Printed in the UK