Quantitative thermal analysis of heat transfer in liquid–liquid biphasic millifluidic droplet flows

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. In this paper, infrared thermography is used to propose a simple quantitative approach toward understanding the thermal behaviour of a liquid-liquid biphasic millifluidic droplet flow under isoperibolic conditions. It is shown that due to the isoperibolic boundary condition, the thermal behaviour at the established periodic state can be managed according to different orders, i.e. either a continuous or fluctuating contribution. A complete analytical solution is proposed for the complex problem model, then a simplified model is proposed. Finally, a simple homogeneous equivalent thin body model approximation with a characteristic coefficient function of a biphasic flow mixing law is sufficient for describing the thermal behaviour of the media under isoperibolic conditions. From this theoretical validation, the experimental results concerning the behaviour of a biphasic oil and droplet flow are presented. An analytical representation law is proposed to quantitatively estimate and predict the thermal behaviour of the flow. Moreover, it is demonstrated that with this new method, the thermophysical properties of the phase can be estimated with a deviation less than 5% from that reported by the suppliers.

The Joule heating problem in silver nanowire transparent electrodes

“…The resulting spatial resolution per pixel is around 250 μm×250 μm. A previously reported calibration method [32,33] was used to retrieve the absolute temperature of the samples (semi-transparent samples) from the raw intensity data provided by the IR camera. More details about the calibration can be found in the supplementary information.…”

Thermal analysis of droplet flow: Numerical, analytical and experimental investigations

“…An experimental study was performed to confirm the hydrodynamic stability of the droplet flow and the repeatability of the length of the slugs as a function of the imposed flow rate ratio via visible-light imaging. This information is not reported here because it is outside the scope of this study [25]. Here, the initial temperatures of the oil phase (T O (0)) and the isoperibolic chip (T p ) were the same, T O (0) = T p = 20 • C ± 0.5 • C; this was achieved using a thermal regulation system (figure 2.B, element 4).…”

“…As a consequence, the temperature established inside the reactor (TEFLON tube or reaction medium) was a result of the heat transfer coefficient for the imposed temperature of the bulk brass and the inner diameter of the tube. Figure 1.B presents a cross-sectional representation of the isoperibolic system; note that 3/4 of the tube was in contact with the brass plate, thus ensuring that the heat transfer occurred through thermal conductance, as stated in a previous publication [25]. A photograph of the experimental set-up is presented in figure 2.A.…”

“…[24], which concerned experimental and numerical analyses of heat transfer inside liquid-liquid flow. Furthermore, when a chemical reaction occurs inside a liquid−liquid flow, the modeling becomes more complex in terms of the number of coupled effects that occur (hydrodynamic, thermal, mass diffusion effects and heat source) [25].…”

Droplet millifluidics for kinetic study of transketolase

“…Indeed, as described elsewhere, 31,32 as PFA is a good thermal insulator (k ¼ 0.25 W M À1 K À1 ) and aluminium an excellent thermal conductor (k ¼ 237 W M À1 K À1 ), the outer temperature of the tube is set by one of the aluminium plates, and heat transfer into air is negligible. Eventually, the small size of the tubing permits fast homogenization of internal temperature and optimum evacuation of calories.…”