Dominant flow mechanisms in falling-film and droplet-mode evaporation over horizontal rectangular tube banks

Dominant Flow Mechanisms in Falling-Film and Droplet Mode Evaporation Over Horizontal Rectangular Tube Banks

Flow visualization with high-speed video of evaporating water films falling over flat horizontal tubes, representative of the external surfaces of microchannel tubes, is presented. Experiments were conducted with 1.4 mm thick and 27 mm tall tubes over a film Reynolds number range of 23 < Re < 126. In addition to a qualitative description of the flow mechanisms, this work quantifies key droplet ...

Falling film evaporation on horizontal tubes with smooth and structured surfaces

Vapor Shear Effects on Falling-Film Mode Transitions Between Horizontal Tubes

A liquid falling between horizontal tubes can take the form of droplets, jets, or a continuous sheet mode, depending on the flow rate. The so-called falling-film flow regime is important to heat and mass transfer, and to maintaining wetted-surface conditions in a falling-film tube bundle, and the performance of such tube bundles is important in many air-conditioning systems. In this paper, we r...

Flow Patterns and Mode Transitions for Falling-Film on Flat Tubes

The transitional Reynolds numbers for different patterns are available and a proposed transitional map is also provided in this paper. The transition of falling-films on flat tubes is studied in this work. Water and ethylene glycol are used as working fluids, for falling-film experiments conducted under adiabatic conditions, without an imposed vapor flow. The flow patterns are recorded using a ...

Steady State Analysis of Nanofuel Droplet ‎Evaporation

The potential for nanofuels as one of the clean sources of energy on account of its enhanced combustion performance coupled with low emissions has been established. Considering the importance of the fuel evaporation phase in the entire combustion process, this work presents an attempt at applying the steady state analysis equations to nanofuel experimental data obtained from the li...