Hydrodynamic stability of thin liquid films flowing down an inclined plane with accompanying heat transfer and interfacial shear

AIChE Journal ◽  
1978 ◽  
Vol 24 (5) ◽  
pp. 803-810 ◽  
Author(s):  
Siu-Ming Yih ◽  
Richard C. Seagrave
Keyword(s):  
Heat Transfer ◽  
Hydrodynamic Stability ◽  
Liquid Films ◽  
Interfacial Shear ◽  
Thin Liquid Films ◽  
Inclined Plane

HEAT TRANSFER IN THIN LIQUID FILMS FLOWING DOWN HEATED INCLINED GROOVED PLATES

2010 ◽  
Vol 2 (5) ◽  
pp. 455-468 ◽  
Author(s):  
Hongyi Yu ◽  
Karsten Loffler ◽  
Tatiana Gambaryan-Roisman ◽  
Peter Stephan
Keyword(s):  
Heat Transfer ◽  
Liquid Films ◽  
Thin Liquid Films

Study of the Fluid Dynamics of Thin Liquid Films Flowing Down a Vertical String With Counterflow of Gas

2015 ◽  
Author(s):  
Zezhi Zeng ◽  
Gopinath Warrier ◽  
Y. Sungtaek Ju
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Film Thickness ◽  
Liquid Film ◽  
Direct Contact ◽  
High Speed ◽  
Small Diameter ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Liquid Coolant

Direct-contact heat transfer between a falling liquid film and a gas stream yield high heat transfer rates and as such it is routinely used in several industrial applications. This concept has been incorporated by us into the proposed design of a novel heat exchanger for indirect cooling of steam in power plants. The DILSHE (Direct-contact Liquid-on-String Heat Exchangers) module consists of an array of small diameter (∼ 1 mm) vertical strings with hot liquid coolant flowing down them due to gravity. A low- or near-zero vapor pressure liquid coolant is essential to minimize/eliminate coolant loss. Consequently, liquids such as Ionic Liquids and Silicone oils are ideal candidates for the coolant. The liquid film thickness is of the order of 1 mm. Gas (ambient air) flowing upwards cools the hot liquid coolant. Onset of fluid instabilities (Rayleigh-Plateau and/or Kapitza instabilities) result in the formation of a liquid beads, which enhance heat transfer due to additional mixing. The key to successfully designing and operating DILSHE is understanding the fundamentals of the liquid film fluid dynamics and heat transfer and developing an operational performance map. As a first step towards achieving these goals, we have undertaken a parametric experimental and numerical study to investigate the fluid dynamics of thin liquid films flowing down small diameter strings. Silicone oil and air are the working fluids in the experiments. The experiments were performed with a single nylon sting (fishing line) of diameter = 0.61 mm and height = 1.6 m. The inlet temperature of both liquid and air were constant (∼ 20 °C). In the present set of experiments the variables that were parametrically varied were: (i) liquid mass flow rate (0.05 to 0.23 g/s) and (ii) average air velocity (0 to 2.7 m/s). Visualization of the liquid flow was performed using a high-speed camera. Parameters such as base liquid film thickness, liquid bead shape and size, velocity (and hence frequency) of beads were measured from the high-speed video recordings. The effect of gas velocity on the dynamics of the liquid beads was compared to data available in the open literature. Within the range of gas velocities used in the experiments, the occurrence of liquid hold up and/or liquid blow over, if any, were also identified. Numerical simulations of the two-phase flow are currently being performed. The experimental results will be invaluable in validation/refinement of the numerical simulations and development of the operational map.

The mechanism for the long-wave instability in thin liquid films

1990 ◽  
Vol 217 ◽  
pp. 469-485 ◽  
Author(s):  
Marc K. Smith
Keyword(s):  
Physical Mechanism ◽  
Thin Liquid Film ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
The Other ◽  
Wave Instability ◽  
Inclined Plane ◽  
Long Wave ◽  
The Many ◽  
Large Groups

A physical mechanism for the long-wave instability of thin liquid films is presented. We show that the many diverse systems that exhibit this instability can be classified into two large groups. Each group is studied using the model of a thin liquid film with a deformable top surface flowing down a rigid inclined plane. In the first group, the top surface has an imposed stress, while in the other, an imposed velocity. The proposed mechanism shows how the details of the energy transfer from the basic state to the disturbance are handled differently in each of these cases, and how a common growth mechanism produces the unstable motion of the disturbance.

Review of Microscale Heat Transfer

1994 ◽  
Vol 47 (9) ◽  
pp. 397-428 ◽  
Author(s):  
A. B. Duncan ◽  
G. P. Peterson
Keyword(s):  
Heat Transfer ◽  
Final Section ◽  
Radiative Heat ◽  
Heat Pipes ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Review Of The Literature ◽  
Conduction Heat Transfer ◽  
Microscale Heat Transfer ◽  
Micro Heat Pipes

A review of the literature in the area of microscale heat transfer is presented to provide a concise overview of the recent advances in this field of study. The review is divided into three major sections with each subdivided into subsections. The first section deals with the effects of size reductions in conduction heat transfer, and includes subsections on laser induced heating on the microscale and conduction in thin films. The second section addresses microscale forced convection and includes subsections on micro heat pipes, microscale boiling, and thin liquid films near the contact line. The final section examines the effects of small length scales on radiative heat transfer. The three major sections are followed by a summary that identifies, consolidates, and summarizes the most important advances in each of these three areas.

Effects Of Surface Solidification on the Stability Of Multi-Layered Liquid Films

1983 ◽  
Vol 105 (1) ◽  
pp. 119-120 ◽  
Author(s):  
S. P. Lin
Keyword(s):  
Stability Problem ◽  
Film Flow ◽  
Liquid Films ◽  
Interfacial Shear ◽  
Capillary Waves ◽  
Inclined Plane ◽  
Air Interface ◽  
The Stability ◽  
Linear Stability Problem ◽  
Special Case

The linear stability problem of a n-layered liquid film with a solidified liquid-air interface is reviewed. The general formulation is applied to the special case of a two-layered film flow down an inclined plane. A stability condition is given explicitly in terms of the density, viscosity and thickness ratios. Based on this condition it is found that solidification of the free surface may have the effects of stabilizing the interfacial shear waves and destabilizing the gravity-capillary waves associated with top-heavy density stratification.

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