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Diesel and gasoline fuels are complex multicomponent fluids which tend to build deposits on walls under certain process conditions. In process engineering or in urea injection systems for exhaust gas treatment similar phaenomena can be seen. Partially wetted wall surfaces may lead to local superheating, caking and deposit deployment. In engine combustion chambers the deposits result in lower engine efficiency and in an increase in emission. Injector tip deposits impair the spray geometry and lead to uncontrolled fuel burning thus leading to uncontrollable emissions.

A basic understanding of the film flow regime, the wetting properties of fluid, the wall materials and the local multiphase heat and masstransfer is required to control and to avoid deposits. As volatile fuel components evaporate the semivolatile fuel components react and build networks of insoluble deposits. Surface properties such as the porosity and capillary effects within pores influence the process.

Up to date no generic experimental investigation of the influencing parameters such as fluid properties, wall materials (including layers and micro topographics), process parameters (pressure, temperature, flow speed, gas compound, …) has been performed and thus a basic understanding is not present, yet.

The main aim of this project is to fill this gap and to provide experimental data to validate numerical and theoretical models. Generic experiments under practical conditions are performed to investigate the film evaporation of aromatic fuel compounds on a thin foil heater. High speed infrared thermography is used to measure the local and temporal temperature profile and heat flux, whereas a chromatic confocal sensor is applied to measure the local film thickness.

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