Numerical and experimental investigation of a vertical LiBr falling film absorber considering wave regimes and in presence of mist flow

The absorber represents the most critical component in absorption systems and one of the key issues. In this component complex heat and mass transfer phenomena during the absorption process takes place simultaneously. For this reason the development of mathematical models validated against experimental data always constitutes useful tools for the design and improvement of falling film absorbers. A testing device has been designed and built to reproduce absorption phenomena in vertical LiBr-H2O falling film absorbers with the primary objective to obtain experimental data. On the other hand, a mathematical model of falling film absorption of H2O vapour in LiBr aqueous solutions has been implemented. Wave regime is considered by including and solving the Free Surface Deflection Equation. The numerical results are validated using the experimental data. During the development of this work, the authors have paid careful attention to the verification of experimental data. Such verification consists of performing energy and mass balances in the fluid film side. Important discrepancies were found in our experimental data. Therefore, an extensive study was carried out in order to find the source of such errors. The conclusion is that there is a drag of LiBr solution in the water vapour which increases with the Re number. This mist flow cannot be measured experimentally, but can be evaluated in an indirect way. The mathematical models have been adapted in order to consider the influence of mist flow. On the other hand, in the literature there are not many experimental works related to falling film absorbers which expose enough information to verify the reliability of their experimental data.Peer ReviewedPostprint (author's final draft

Handmade films and artist-run labs. The chemical sites of film’s counterculture

This article addresses handmade films and especially artist-run labs as sites of hands-on film culture that reactivate moments and materials from media history. Drawing on existing research, discourses and discussions with contemporary experimental filmmakers affiliated with labs or practicing their work in relation to film lab infrastructure, we focus on these sites of creation, preservation and circulation of technical knowledge about analog film. But instead of reinforcing the binary of analog vs. digital, we argue that the various material practices from self-made apparatuses to photochemistry and film emulsions are ways of understanding the multiple materials and layered histories that define post-digital culture of film. This focus links our discussion with some themes in media archaeology (experimental media archaeology as a practice) and to current discussions about labs as arts and humanities infrastructure for collective project and practice-based methods

The experimental study and numerical simulation of falling liquid film flow on horizontal tubes

This research is motivated by two observations: No report has been found so far in studies of water falling film up to 100 mm intertube spacing. No simulation analysis of film thickness under influence of intertube spacing in 3 dimensional models. Therefore, to the best of author’s knowledge, this research aims to illuminate the effects of intertube spacing between horizontal tubes on water falling film. An experimental investigation of water falling film temperature was conducted to explore the characteristics of heat transfer coefficients. In this study, the intertube spacing from smallest size of 8 mm and up to 100 mm were analyzed for Reynolds number range of 300 to 3300. The experimental data was extracted from calibrated test rig and the effect is investigated using numerical study. On the other hand, the effect of film thickness is numerically investigated for intertube spacing range of 10 mm to 40 mm. The numerical simulation was presented using the Volume of Fluid (VOF) technique where it is capable in determining temperatures and thickness of water falling film under influence of ambient factors. The experimental results reveal that intertube spacing of 133 mm produced the maximum heat transfer coefficient of 6 kW/m² K with percentage of error below 7%. The results of the numerical simulation indicate that the 40 mm intertube spacing presented the minimal average film thickness of 0.3 mm within ± 50% errors. Implications of the results and future research directions are also presented

An Experimental Study of Fertility Behaviour in South West of Nigeria

The study evaluated the impact of an educational film on the fe rtility and health behaviour of selected Yoruba speaking communities in South West Nigeria. A field controlled experiment was utilized with 5 treatment groups and 5 controlled groups. Intact population units was adopted in the experimental sites and the mean age of participants was 38 years. Results indicated difference between the experimental and control groups in fertility behaviour. Clinic attendanceforfamily planning also increased as a result of projection of the film