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Non-intrusive CdSe-based quantum dots for sensing pressure and temperature in lubricated contacts

Tarek Seoudi 1, 2
Abstract : This thesis is dedicated to the measurement of local pressure and temperature and to compare the heat generation in all-steel and silicon nitride-steel (hybrid) elastohydrodynamic (EHD) contacts. The ultimate goal of this work is to develop a new non-intrusive in situ technique, exploiting the sensitivity of the photoluminescence (PL) of CdSe/CdS/ZnS quantum dots (QDs) to pressure and temperature. Dispersible in small concentration in lubricants, it is shown that the QDs doesn’t modify the rheological behavior of the carrier fluid and that shearing is not perturbative to the QDs PL response. The calibration of QDs in the suspension confirms the QDs PL dependence on temperature and pressure. The in situ measurements were conducted in EHD contacts using a ball-on-disc test rig. Comparisons between pressure and temperature measurements and predictions, using an in–house finite element thermal EHD model, showed a good agreement which demonstrates the feasibility of the proposed methodology. The effects of sliding and normal loading on pressure, temperature and heat generation are indicated. The effect of the thermal properties of the solid materials is underlined and the partition of the generated heat between the contacting solids is investigated. The energy equilibrium between the mechanical energy and the internal thermal energy generated by compression and shearing is demonstrated by comparing experimental power losses and numerical heat generation, in steel-steel and hybrid contacts.
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Submitted on : Thursday, July 16, 2020 - 12:30:39 PM
Last modification on : Monday, July 20, 2020 - 5:33:56 PM


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  • HAL Id : tel-02900672, version 1


Tarek Seoudi. Non-intrusive CdSe-based quantum dots for sensing pressure and temperature in lubricated contacts. Mechanical engineering [physics.class-ph]. Université de Lyon, 2020. English. ⟨NNT : 2020LYSEI009⟩. ⟨tel-02900672⟩



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