The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform
S S Alam - One of the best experts on this subject based on the ideXlab platform.
-
experimental study of heat transfer to boiling binaries in a Reboiler Tube
International Journal of Heat and Mass Transfer, 1996Co-Authors: M Kamil, S S AlamAbstract:Abstract An experimental investigation of heat transfer to boiling binaries under natural convective flow through a Reboiler Tube has been carried out to study the effect of composition on heat transfer coefficient. The heat transfer section consisted of an electrically heated stainless steel Tube of 25.56 mm i.d. and 1900 mm long. Three binary systems: methanol-water, benzene toluene and water-ethylene glycol were used for a variety of concentrations. The heat flux values ranged from about 4.1 to 33.0 kW m −2 . The liquid submergence levels were maintained around 100, 75, 50 and 30%. A significant reduction in the heat transfer coefficient is observed for binary mixtures attributable to the effect of mass diffusion on heat transfer. The heat transfer coefficients in the non-boiling and boiling regions for all the binary mixtures have been correlated by two separate correlations in terms of dimensionless groups.
-
An experimental study for predicting circulation rates in a Reboiler Tube
Indian Journal of Chemical Technology, 1994Co-Authors: Mohd Kamila, S S Alam, H AliaAbstract:An experimental investigation of heat transfer to boiling liquids under natural convective flow through a vertical Tube thennosiphon Reboiler has been carried out to study the effect of heat flux and liquid submergence on circulation rates. Three. test liquids namely: water, methanol and ethylene glycol were used to cover a wide range of boiling points and thennophysical properties. The test section was an electrically heated stainless steel Tube 25.56 mm i.d. and 1900 mm length. The uniform heat fluxes in the range of 4.1 to 43 kW/m2 were employed while inlet liquid subcooling varied from 0.5 to 11.6°C. The liquid submergence levels were maintained around 100, 75, 50 and 30%. Circulation rates for all test liquids have been correlated in terms of dimensionless groups. Vertical thermosiphon Reboilers consitute one of the most widely used types of heat transfer units in chemical, petrochemical and petroleum industries where significant capital investment is represented by Reboilers, evaporators and vaporizers. They owe their popularity to excellent heat transfer rates, mechanical simplicity and no expenditure of power to circulate the process fluid. The process fluid entering the Tubes of heat exchanger gets heated and moves upwards due to density difference between the liquid and boiling two phase fluid. The boiling of liquids in vertical Tubes of closed loop circulation systems as above, finds its application also extending to refrigeration, power plants and nuclear reactors. The process fluid entering the vertical Tubes of heat exchanger receives the heat from the heat flux supplied. When vaporization takes place, the specific volume of the fluid is increased, resulting in its upward movement while the liquid is siphoned from the adjoining cold leg. Thus, a net flow through the circulation loop sets in. The prediction of rates of heat transfer and thermally induced flow (circulation rate) is the primary requirement for the design and efficient operation of the thermosiphon Reboilers. A number of studies have been reported in literature to predict the rate of heat transfer, but very little information is available for the estimation of circulation rates":". Most of these studies were over a limited range of variables for very few systems. Inspite of the industrial importance of the natural circulation boiling of liquids in vertical Tubes where flow and heat transfer interact with each other, no systematic study seems to have been conducted to obtain the exclusive effect of important parameters on circulation rates. In the present investigation, an attempt has been made to study the exclusive effect of heat flux and submergence on circulation rates in a single vertical Tube thermosiphon Reboiler.
-
boiling incipience in a Reboiler Tube
Industrial & Engineering Chemistry Research, 1991Co-Authors: Hamid Ali, S S AlamAbstract:This heating surface and liquid temperature distributions were experimentally obtained to identify the boiling incipience conditions in a single vertical Tube thermosiphon Reboiler with water, acetone, ethanol, and ethylene glycol as test liquids. The test section was an electrically heated stainless steel Tube of 25.56-mm i.d. and 1900 mm long. The uniform heat flux values were used in the range of 3800--40 000 W/m{sup 2}, while inlet liquid subcooling were varied from 0.2 to 45.5{degrees} C. The liquid submergence was maintained around 100, 75, 50 and 30%. All the data were generated at 1-atm pressure. The maximum superheats attained around boiling incipience were taken from the wall temperature distributions and correlated with heat flux and physical properties of liquids using the expression of Yin and Abdelmessih. The heated sections required for onset of fully developed boiling with net vapor generation were determined assuming a thermal equilibrium model. In this paper a dimensionless correlation relating these values with heat flux, liquid subcooling, and submergence is proposed.
M Kamil - One of the best experts on this subject based on the ideXlab platform.
-
analysis of incipience of nucleate boiling in a Reboiler Tube
Aiche Journal, 2007Co-Authors: M Kamil, M Shamsuzzoha, Abdul M HakeemAbstract:An analysis has been carried out to predict the boiling incipience with natural circulation flow in a Reboiler Tube. An equation has been proposed to estimate the wall superheat for different types of liquids covering a wide range of thermo physical properties. Incipience in liquid films is influenced both by turbulent eddies and liquid submergence. This approach utilizes physical parameters of commonly accepted incipience models and takes into account the effects of turbulent eddies and submergence. The results predicted from the theoretical analysis were found to be consistent with the experimental data, having average absolute relative error of 15.42 percent. © 2006 American Institute of Chemical Engineers AIChE J, 2006
-
experimental study of heat transfer to boiling binaries in a Reboiler Tube
International Journal of Heat and Mass Transfer, 1996Co-Authors: M Kamil, S S AlamAbstract:Abstract An experimental investigation of heat transfer to boiling binaries under natural convective flow through a Reboiler Tube has been carried out to study the effect of composition on heat transfer coefficient. The heat transfer section consisted of an electrically heated stainless steel Tube of 25.56 mm i.d. and 1900 mm long. Three binary systems: methanol-water, benzene toluene and water-ethylene glycol were used for a variety of concentrations. The heat flux values ranged from about 4.1 to 33.0 kW m −2 . The liquid submergence levels were maintained around 100, 75, 50 and 30%. A significant reduction in the heat transfer coefficient is observed for binary mixtures attributable to the effect of mass diffusion on heat transfer. The heat transfer coefficients in the non-boiling and boiling regions for all the binary mixtures have been correlated by two separate correlations in terms of dimensionless groups.
Abdul M Hakeem - One of the best experts on this subject based on the ideXlab platform.
-
analysis of incipience of nucleate boiling in a Reboiler Tube
Aiche Journal, 2007Co-Authors: M Kamil, M Shamsuzzoha, Abdul M HakeemAbstract:An analysis has been carried out to predict the boiling incipience with natural circulation flow in a Reboiler Tube. An equation has been proposed to estimate the wall superheat for different types of liquids covering a wide range of thermo physical properties. Incipience in liquid films is influenced both by turbulent eddies and liquid submergence. This approach utilizes physical parameters of commonly accepted incipience models and takes into account the effects of turbulent eddies and submergence. The results predicted from the theoretical analysis were found to be consistent with the experimental data, having average absolute relative error of 15.42 percent. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Hamid Ali - One of the best experts on this subject based on the ideXlab platform.
-
boiling incipience in a Reboiler Tube
Industrial & Engineering Chemistry Research, 1991Co-Authors: Hamid Ali, S S AlamAbstract:This heating surface and liquid temperature distributions were experimentally obtained to identify the boiling incipience conditions in a single vertical Tube thermosiphon Reboiler with water, acetone, ethanol, and ethylene glycol as test liquids. The test section was an electrically heated stainless steel Tube of 25.56-mm i.d. and 1900 mm long. The uniform heat flux values were used in the range of 3800--40 000 W/m{sup 2}, while inlet liquid subcooling were varied from 0.2 to 45.5{degrees} C. The liquid submergence was maintained around 100, 75, 50 and 30%. All the data were generated at 1-atm pressure. The maximum superheats attained around boiling incipience were taken from the wall temperature distributions and correlated with heat flux and physical properties of liquids using the expression of Yin and Abdelmessih. The heated sections required for onset of fully developed boiling with net vapor generation were determined assuming a thermal equilibrium model. In this paper a dimensionless correlation relating these values with heat flux, liquid subcooling, and submergence is proposed.
M Shamsuzzoha - One of the best experts on this subject based on the ideXlab platform.
-
analysis of incipience of nucleate boiling in a Reboiler Tube
Aiche Journal, 2007Co-Authors: M Kamil, M Shamsuzzoha, Abdul M HakeemAbstract:An analysis has been carried out to predict the boiling incipience with natural circulation flow in a Reboiler Tube. An equation has been proposed to estimate the wall superheat for different types of liquids covering a wide range of thermo physical properties. Incipience in liquid films is influenced both by turbulent eddies and liquid submergence. This approach utilizes physical parameters of commonly accepted incipience models and takes into account the effects of turbulent eddies and submergence. The results predicted from the theoretical analysis were found to be consistent with the experimental data, having average absolute relative error of 15.42 percent. © 2006 American Institute of Chemical Engineers AIChE J, 2006
