Additive Adsorption and Interfacial Characteristics of Nucleate Pool Boiling in Aqueous Surfactant Solutions

2005 ◽  
Vol 127 (7) ◽  
pp. 684-691 ◽  
Author(s):  
Juntao Zhang ◽  
Raj M. Manglik
Keyword(s):  
Contact Angle ◽  
Pure Water ◽  
Pool Boiling ◽  
Dynamic Surface Tension ◽  
Nucleate Pool Boiling ◽  
Dynamic Surface ◽  
Wetting Contact Angle ◽  
Optimum Heat ◽  
Adsorption Desorption ◽  
And Control

Interfacial phenomena and ebullient dynamics in saturated nucleate pool boiling of aqueous solutions of three surfactants that have different molecular weight and ionic nature are experimentally investigated. The additive molecular mobility at interfaces manifests in a dynamic surface tension behavior (surfactant adsorption–desorption at the liquid–vapor interface), and varying surface wetting (contact angle) with concentration (surfactant physisorption at the solid–liquid interface). This tends to change, enhance, and control the boiling behavior significantly, and an optimum heat transfer enhancement is obtained in solutions at or near the critical micelle concentration (CMC) of the surfactant. Furthermore, wettability (contact angle) is observed to be a function of the molecular makeup of the reagent, and shows distinct regions of change along the adsorption isotherm that are associated with the aggregation mode of adsorbed ions at the solid–water interface. This distinguishably alters the ebullience from not only that in pure water, but also between pre- and post-CMC solutions. Increased wetting tends to suppress nucleation and bubble growth, thereby weakening the boiling process.

Pool Boiling Heat Transfer in Aqueous Solutions of an Anionic Surfactant

2000 ◽  
Vol 122 (4) ◽  
pp. 708-715 ◽  
Author(s):  
V. M. Wasekar ◽  
R. M. Manglik
Keyword(s):  
Anionic Surfactant ◽  
Pure Water ◽  
Pool Boiling ◽  
Sodium Dodecyl ◽  
Dynamic Surface Tension ◽  
Nucleate Boiling ◽  
Optimum Level ◽  
Lauryl Sulfate ◽  
Dynamic Surface ◽  
Influence Of Temperature On

Saturated nucleate pool boiling of aqueous surfactant solutions on a horizontal cylindrical heater has been experimentally investigated. Sodium dodecyl or lauryl sulfate (SDS or SLS), an anionic surfactant, is employed. Boiling performance, relative to that for pure water, is found to be enhanced significantly by the presence of SDS, with an early onset of nucleate boiling. An optimum level of enhancement is observed in solutions at or near critical micelle concentration of the surfactant; the enhancement, however, decreases considerably in higher concentration solutions. The dynamic surface tension measurements indicate a substantial influence of temperature on the overall adsorption isotherm. The diffusion kinetics of surfactant molecules and micelles is, therefore, expected to be quite different at boiling temperature than at room temperature. This greatly modifies the boiling mechanism that is generally characterized by the formation of smaller-size bubbles with increased departure frequencies, and a decreased tendency to coalesce which causes considerable foaming. [S0022-1481(00)00704-0]

Visualization of Multiscale Processes - Bubble Dynamics in Surface Active Colloids

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
S. Manoharan ◽  
D. Kalaikadal ◽  
R. M. Manglik ◽  
E. Iskrenova-Ekiert ◽  
S. S. Patnaik
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Pure Water ◽  
Dynamic Surface Tension ◽  
Air Flow Rate ◽  
Dynamic Surface ◽  
Multi Scale ◽  
Macro Scale ◽  
Dynamics Simulations ◽  
Adsorption Desorption

The growth dynamics of isolated gas bubbles from a submerged capillary-tube orifice in a pool of aqueous solution of Cetyl Trimethyl Ammonium Bromide (CTAB) was studied by multi-scale modeling. The macro-scale bubble ebullience is controlled by the molecular scale surfactant adsorption/desorption on the liquid-gas interface. Molecular dynamics simulations were carried out to predict the interfacial adsorption/desorption kinetics. The results of the molecular dynamics simulations were input to the volume-of-fluid based macro-scale computations. The size and shape of bubbles from incipience to departure were measured using high speed videography for model validation. Predictions of the multi-scale model agree with the experimental measurements of bubble size evolution and bubble diameter at departure. The surfactant mass transfer and adsorption on the liquid gas interface gives rise to dynamic surface tension. As a result of the surfactant presence, the bubble departure diameters were smaller in CTAB solution compared to pure water. Furthermore, dynamic surface tension behavior of CTAB makes the bubble departure diameter a function of bubble Reynolds number (Re based on the orifice diameter and air flow rate). At low flow rates or low Re, the bubble departure diameters are smaller than those in water. As the air flow rate increases, the bubble departure diameters tend towards those in pure water. The authors gratefully acknowledge funding from AFOSR Thermal Science Program and AFRL DoD Supercomputing Resource Center for computing time and resources.

Pool Boiling Heat Transfer in Aqueous Surfactant Solutions

1999 ◽  
Author(s):  
Vivek M. Wasekar ◽  
Raj M. Manglik
Keyword(s):  
Pure Water ◽  
Pool Boiling ◽  
Sodium Dodecyl ◽  
Dynamic Surface Tension ◽  
Nucleate Boiling ◽  
Optimum Level ◽  
Lauryl Sulfate ◽  
Dynamic Surface ◽  
Surfactant Solutions ◽  
Influence Of Temperature On

Abstract Saturated, nucleate pool boiling of aqueous surfactant solutions on a horizontal, cylindrical heater has been experimentally investigated. Sodium dodecyl or lauryl sulfate (SDS or SLS), an anionic surfactant is employed. Boiling performance, relative to that for pure water, is found to be enhanced significantly by the presence of SDS, with an early onset of nucleate boiling. An optimum level of enhancement is observed in solutions at or near critical micelle concentration of the surfactant; the enhancement decreases considerably in higher concentration solutions. The dynamic surface tension measurements indicate a considerable influence of temperature on the overall adsorption isotherm. The diffusion kinetics of surfactant molecules and micelles is, therefore, expected to be quite different at boiling temperature than at room temperature. This greatly modifies the boiling mechanism, that is generally characterized by the formation of smaller-size bubbles with increased departure frequencies, and a decreased tendency to coalesce which causes considerable foaming.

Experimental Study of Effects of Interfacial Properties on Nucleate Pool Boiling in Water

2011 ◽  
Author(s):  
U. Verma ◽  
R. M. Manglik ◽  
M. A. Jog
Keyword(s):  
Heat Transfer ◽  
Interfacial Tension ◽  
Aqueous Solutions ◽  
Pool Boiling ◽  
Interfacial Properties ◽  
Dynamic Surface Tension ◽  
Chain Molecule ◽  
Nucleate Pool Boiling ◽  
Dynamic Surface ◽  
Fluorinated Carbon

Saturated, nucleate pool boiling on a horizontal, cylindrical heater in aqueous solutions of a fluorosurfactant (FS-50) is experimentally investigated. FS-50 is a long chain molecule of fluorinated carbon atoms, and it produces very low dynamic surface tension (varying from 72.5 mN/m to 17.4 mN/m with surface age and concentration) in aqueous solutions. Boiling curves (given by the variation of heat flux with wall superheat) and photographic records of the ebullient behavior are presented, along with a detailed characterization of the interfacial tension of the solutions. It is seen that nucleate pool boiling behavior of water is significantly altered by the addition of FS-50, and the heat transfer is increased. The enhancement in boiling is seen to stem from the substantial changes in the interfacial properties. A rather complex interplay of dynamic interfacial tension and surface wetting due to varying surfactant concentrations is seen to affect the phase change ebullient dynamics and associated heat transfer.

Experimental Investigation of Low Weber Number Post-Impact Drop Spreading on Solid Substrates

2010 ◽  
Author(s):  
Milind A. Jog ◽  
Raj M. Manglik
Keyword(s):  
Surface Tension ◽  
High Speed ◽  
Pure Water ◽  
Surfactant Solution ◽  
Video Camera ◽  
Dynamic Surface Tension ◽  
Temporal Variations ◽  
Dynamic Surface ◽  
Post Impact ◽  
Triton X

The post-impact spreading and recoil behaviors of droplets of pure liquids (water and ethanol) and aqueous solution of Triton X-100 (a surfactant) on a dry horizontal hydrophilic (glass) substrate are investigated for low Weber numbers. The evolution of drop shape during spreading and recoil are captured using a high-speed (4,000 frames per second) digital video camera. Digital image-processing was used to determine the spread and height of the liquid film on the surface from each frame. Unlike pure liquids, the liquid-gas interfacial tension for surfactant solution is a function of surface age, where surface tension is that of the solvent at zero time and then reaches an equilibrium value with increasing surface age. Furthermore, the equilibrium surface tension is a function of the surfactant concentration, which decreases from that of the solvent at zero concentration to that at the critical micelle concentration (CMC), and remains essentially constant thereafter. The surface tension of aqueous Triton X-100 solution varies from that of pure water to nearly that of ethanol. As such the comparison of transient droplet-impact-spreading-recoil behavior of the three liquids, or their temporal variations of the spread and the flattening factor, provides a basis for understanding the role of dynamic surface tension and surface wettability.

Effects of Surface Tension and Binary Diffusion on Pool Boiling of Dilute Solutions: An Experimental Assessment

1999 ◽  
Vol 121 (2) ◽  
pp. 488-493 ◽  
Author(s):  
S. G. Kandlikar ◽  
L. Alves
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Contact Angle ◽  
Heat Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Pure Water ◽  
Pool Boiling ◽  
Binary Diffusion ◽  
Water Value ◽  
Diffusion Effects

Pool boiling heat transfer with dilute binary mixtures introduces two additional effects due to binary diffusion, and due to change in the surface tension. The secondary effects due to changes in contact angle and wetting characteristics may also play a role. The present study focuses on identifying these effects for dilute aqueous solutions of ethylene glycol. Pool boiling experiments are conducted to generate data in the range of one to ten percent mass fraction. It is found that in the low concentration region, the binary diffusion effects are insignificant for aqueous solutions of ethylene glycol, and a slight improvement in heat transfer coefficient is observed over the pure water value. The binary diffusion effects are related to a volatility parameter, V1. The heat transfer coefficient does not degrade in the region where V1 < 0.03, and the surface tension does not change appreciably compared to pure water value. This points to the possibility that the changes in contact angle and wetting characteristics play an important role in the pool boiling heat transfer.

Comparisons of Aqueous Surfactant Solutions for Nucleate Pool Boiling

2016 ◽  
Author(s):  
Birce Dikici ◽  
Basim Q. A. Al-Sukaini
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Pure Water ◽  
Pool Boiling ◽  
Lauryl Sulfate ◽  
Nucleate Pool Boiling ◽  
Transfer Enhancement ◽  
Surfactant Solutions ◽  
Boiling Heat Transfer Coefficient ◽  
Important Possibility

In this study, nucleate pool boiling of surfactant solutions are investigated. The surfactants chosen for the study are an ionic sodium lauryl sulfate (SLS), nonionic ECOSURF™ EH-14, and nonionic ECOSURF™ SA-9. It is observed that adding a small amount of surfactant alters the water boiling phenomenon considerably. Boiling curves for different concentrations are shifted to the left. The wall temperature dropped with an increase in the concentration of aqueous surfactant solutions. Also, it is found that the boiling heat transfer enhancement of SLS is higher than that of EH-14 and SA-9 compared to water. Boiling heat transfer coefficient (h) enhancements compared to water are 46%, 30%, and 21%. (for SLS, for EH-14 and for SA-9 respectively) Boiling visualization shows that boiling with surfactant solutions compared with that in pure water is more vigorous. Bubbles are smaller, activate continuously, and collapse quickly. Also, the bubble departure frequency is observed to be higher than that of pure water. Results prove that there is an important possibility to enhance the boiling application processes by environmentally friendly EH-14, and SA-9 additives. Experimentation can be extended for searching other surfactants in order to find their most efficient quantity in water for boiling heat transfer.

Adsorption of C14EO8 at the interface between its aqueous solution drop and air saturated by different alkanes vapor

2017 ◽  
Vol 19 (3) ◽  
pp. 2193-2200 ◽  
Author(s):  
R. Miller ◽  
E. V. Aksenenko ◽  
V. I. Kovalchuk ◽  
V. B. Fainerman
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Pure Water ◽  
Dynamic Surface Tension ◽  
Dynamic Surface ◽  
Equilibrium Surface ◽  
Equilibrium Surface Tension

The dynamic and equilibrium surface tension for drops of aqueous C14EO8 solutions at the interface to pure air or pentane, hexane, heptane and toluene saturated air, and the dynamic surface tension of pure water at these interfaces are presented.

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