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Experimental Explorations in Pool Boiling of Aqueous Surfactant Solutions

Subedi, Jeewan
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543994284010763

Abstract Details

2018, MS, University of Cincinnati, Engineering and Applied Science: Mechanical Engineering.
Comparative study of interfacial properties and pool boiling of water along with three surfactant additives is conducted. Each are selected from one charge group; anionic SDS, cationic CTAB and zwitterionic FS-50. Experiments are first conducted to determine interfacial properties such as dynamic and equilibrium surface tension of the surfactant solutions and the contact angle or wettability at the liquid-solid interface. Critical micelle concentration (CMC) of three surfactant samples SDS, CTAB and FS-50 is determined from their respective equilibrium gas liquid interfacial isotherm with varying concentration. Dynamic surface tension for three surfactant solutions at CMC are measured and are fitted using prediction model obtained by Hua and Rosen. Due to difference in molecular weight, ionic group, nature and characteristics of these three surfactants there are distinct differences in their dynamic surface tension characteristics. The data shows time range of variation of surface tension of SDS from 10^-7 to 1 seconds at CMC. Likewise, variation in surface tension of CTAB at CMC is in order of 10^-3 to 1 second. For FS-50 on the other hand, there is a sharp change in surface tension value in short time span in order of 10^-1 to 10 seconds. Static contact angle measurement is done for varying concentration to determine wettability for these three surfactant solutions by sessile drop method. Contact angle first decreased sharply with increase in concentration and became almost constant. FS-50 was found to be highly surface wetting while CTAB had lowest wettability among three surfactant samples. Saturated nucleate pool boiling experiment is conducted for de-ionized, distilled water in a horizontal cylindrical heater at atmospheric pressure to develop boiling curve (q" vs ?T). The process is repeated several times to verify repeatability of data for the boiling experiment. The boiling curve for water is determined which is used as a basis to characterize heat transfer of other surfactant solutions. Nucleate pool boiling experiment for both increasing and decreasing heat flux is conducted for each of the three surfactant solutions at CMC. The pool boiling results for surfactant solutions show shift in the boiling curve towards left from water boiling curve which shows enhancement in heat transfer. The enhancement in heat transfer is of different magnitude for each surfactant solution at CMC. Dimensionless heat transfer coefficient is calculated for each surfactant solution at CMC and plotted against heat flux. Heat transfer in surfactant solutions is a result of change in interfacial properties of these surfactants. Additionally, surface roughness is seen to have higher impact in heat transfer of lower surface wetting fluids like water while it does not appear to significantly impact heat transfer in highly surface wetting fluids like surfactant solutions. Due to complex conjugate nature of pool boiling of surfactant solutions, further research to independently characterize each variable impacting heat transfer is recommended for full understanding of combined effect of these variables on heat transfer enhancement and development of generalized correlation for heat transfer in surfactants.
Raj Manglik, Ph.D. (Committee Chair)
Je-Hyeong Bahk, Ph.D. (Committee Member)
Milind Jog, Ph.D. (Committee Member)
77 p.
Engineering
heat transfer enhancement; nucleate pool boiling; boiling in surfactants; interfacial properties of surfactants

Recommended Citations

Citations

  • Subedi, J. (2018). Experimental Explorations in Pool Boiling of Aqueous Surfactant Solutions [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543994284010763

    APA Style (7th edition)

  • Subedi, Jeewan. Experimental Explorations in Pool Boiling of Aqueous Surfactant Solutions. 2018. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543994284010763.

    MLA Style (8th edition)

  • Subedi, Jeewan. "Experimental Explorations in Pool Boiling of Aqueous Surfactant Solutions." Master's thesis, University of Cincinnati, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543994284010763

    Chicago Manual of Style (17th edition)

ucin1543994284010763
391
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