Munir Eraghubi - Academia.edu (original) (raw)
Papers by Munir Eraghubi
Ehd Augmented Heat Transfer During Upward Bubbly Flow Boiling for Low to Medium Frequency Ac Electric Fields
SSRN Electronic Journal
International Journal of Thermofluids
An experimental investigation of upward flow boiling of HFE-7000 has been conducted in a vertical... more An experimental investigation of upward flow boiling of HFE-7000 has been conducted in a vertical tube under a high frequency alternating current (AC) electric field with the aid of high speed photography. Importantly, the test section was coated with 600 nm transparent Indium Tin Oxide (ITO) layer allowing visual access to the boiling dynamics within the tube while simultaneously functioning as an electrical heater element for the heat transfer and electrode for establishing the electric field. Experiments were performed for a constant mass flux of G=100 kg/m 2 s, inlet subcooling of 2K, applied heat flux ranging between 5 to 50 kW/ m 2 , applied voltages from 0 to 10 kV p-p AC and frequencies of 100 Hz, 1000 Hz and 10,000 Hz. For the 100 Hz applied frequency, the evidence supports the hypothesis that there are strong electrophoretic forces augmenting the heat and mass transfer phenomenon, with better than twofold enhancement in the heat transfer at low heat fluxes. This tends to diminish with applied heat flux. Interestingly, the EHD enhancement increases for all heat flux levels when the frequency is increased to 1000 Hz, with an observed change to polarization-force dominated EHD augmentation. Increasing further to 10,000 Hz results in diminished enhancement, resulting in a peak enhancement at 1000 Hz.
Eraghubi Munir Integration of Rapid Prototyping Technology With Cad Master of Engineering Thesis Dublin City University, 2004
Without his support and continuous advice throughout this research it would not have been possibl... more Without his support and continuous advice throughout this research it would not have been possible to finish this thesis. 1 am honoured to have him as my supervisor for this research. Many thanks to professor M.S.J Hashmi for his guidance and helpful advice. Thanks to Keith Hickey, school IT system administrator, for offering his time and expertise when required. Thanks to my fellow graduate students for their spontaneous support and comments.
Experimental Thermal and Fluid Science, 2018
Forced convective boiling experiments with HFE7000 as the working fluid were conducted for upward... more Forced convective boiling experiments with HFE7000 as the working fluid were conducted for upward flow in a vertical tube at 122 kPa (1.2 bar), inlet subcooling of 2K and mass flux ranging between 50 and 150 kg/m 2 s. The experimental facility consisted of a smooth 8 mm inside diameter optically transparent sapphire tube with overall length of 120 mm. A central 80 mm long section was coated with optically transparent and electrically conductive Indium Tin Oxide (ITO) functioning as a heater to facilitate boiling whilst allowing for visual observation of the two-phase flow. Tests were performed by fixing the flow rate and progressively increasing the heat flux. The results show that after the onset of nucleate boiling, the flow regime is bubbly and increasing the heat flux acts to increase the boiling heat transfer coefficient due to increased nucleation site density, bubble frequency and size. This results in a linear increase in the boiling curve. However, once slug flow is established, the slope of the boiling curve increases indicating that this flow regime augments the heat transfer positively. Overall, the boiling curves were insensitive to mass flux for the range tested. However, the inflection on the boiling curve, associated with flow regime transition from bubbly to slug, was observed to be sensitive to mass flux. The Chen convective boiling heat transfer correlation was compared with the measured data showing reasonable agreement. A modified Chen correlation has been proposed for low mass flux convective boiling which predicts the measured data more accurately.
Ehd Augmented Heat Transfer During Upward Bubbly Flow Boiling for Low to Medium Frequency Ac Electric Fields
SSRN Electronic Journal
International Journal of Thermofluids
An experimental investigation of upward flow boiling of HFE-7000 has been conducted in a vertical... more An experimental investigation of upward flow boiling of HFE-7000 has been conducted in a vertical tube under a high frequency alternating current (AC) electric field with the aid of high speed photography. Importantly, the test section was coated with 600 nm transparent Indium Tin Oxide (ITO) layer allowing visual access to the boiling dynamics within the tube while simultaneously functioning as an electrical heater element for the heat transfer and electrode for establishing the electric field. Experiments were performed for a constant mass flux of G=100 kg/m 2 s, inlet subcooling of 2K, applied heat flux ranging between 5 to 50 kW/ m 2 , applied voltages from 0 to 10 kV p-p AC and frequencies of 100 Hz, 1000 Hz and 10,000 Hz. For the 100 Hz applied frequency, the evidence supports the hypothesis that there are strong electrophoretic forces augmenting the heat and mass transfer phenomenon, with better than twofold enhancement in the heat transfer at low heat fluxes. This tends to diminish with applied heat flux. Interestingly, the EHD enhancement increases for all heat flux levels when the frequency is increased to 1000 Hz, with an observed change to polarization-force dominated EHD augmentation. Increasing further to 10,000 Hz results in diminished enhancement, resulting in a peak enhancement at 1000 Hz.
Eraghubi Munir Integration of Rapid Prototyping Technology With Cad Master of Engineering Thesis Dublin City University, 2004
Without his support and continuous advice throughout this research it would not have been possibl... more Without his support and continuous advice throughout this research it would not have been possible to finish this thesis. 1 am honoured to have him as my supervisor for this research. Many thanks to professor M.S.J Hashmi for his guidance and helpful advice. Thanks to Keith Hickey, school IT system administrator, for offering his time and expertise when required. Thanks to my fellow graduate students for their spontaneous support and comments.
Experimental Thermal and Fluid Science, 2018
Forced convective boiling experiments with HFE7000 as the working fluid were conducted for upward... more Forced convective boiling experiments with HFE7000 as the working fluid were conducted for upward flow in a vertical tube at 122 kPa (1.2 bar), inlet subcooling of 2K and mass flux ranging between 50 and 150 kg/m 2 s. The experimental facility consisted of a smooth 8 mm inside diameter optically transparent sapphire tube with overall length of 120 mm. A central 80 mm long section was coated with optically transparent and electrically conductive Indium Tin Oxide (ITO) functioning as a heater to facilitate boiling whilst allowing for visual observation of the two-phase flow. Tests were performed by fixing the flow rate and progressively increasing the heat flux. The results show that after the onset of nucleate boiling, the flow regime is bubbly and increasing the heat flux acts to increase the boiling heat transfer coefficient due to increased nucleation site density, bubble frequency and size. This results in a linear increase in the boiling curve. However, once slug flow is established, the slope of the boiling curve increases indicating that this flow regime augments the heat transfer positively. Overall, the boiling curves were insensitive to mass flux for the range tested. However, the inflection on the boiling curve, associated with flow regime transition from bubbly to slug, was observed to be sensitive to mass flux. The Chen convective boiling heat transfer correlation was compared with the measured data showing reasonable agreement. A modified Chen correlation has been proposed for low mass flux convective boiling which predicts the measured data more accurately.