Nucleate pool boiling is typically characterized by cyclic growth and departure of vapor bubbles from a heated wall. It has been experimentally observed that the contact angle at the bubble base varies during the ebullition cycle. In the present numerical study, a static contact angle model and dynamic contact angle models based on the contact line velocity and the sign of the contact line velo...

We investigate the influence of volume viscosity on a planar shock/hydrogen bubble interaction. The numerical model is two dimensional and involve complex chemistry and detailed transport. All transport coefficients are evaluated using algorithms which provide accurate approximations rigourously derived from the kinetic theory of gases. Our numerical results show that volume viscosity has an im...

We describe a high-performance colorimeter with an electronic bubble gate for use with miniaturized continuous-flow analyzers. The colorimeter has a flow-through cuvette with optically flat quartz windows that allows a bubbled stream to pass freely without any breakup or retention of bubbles. The fluid volume in the light path is only 1.8 mul. The electronic bubble gate selectively removes that...

Gas bubbles in water act as oscillators with a natural frequency inversely proportional to their radius and a quality factor determined by thermal, radiation, and viscous losses. The linear dynamics of spherical bubbles are well understood, but the excitation mechanism leading to sound production at the moment of bubble creation has been the subject of speculation. Experiments and models presen...

In this study, the nonlinear effect of contactless bubble–bubble interactions in inertial micropumps is characterized via reduced parameter one-dimensional and three-dimensional computational fluid dynamics (3D CFD) modeling. A pump model developed to account for bubble-bubble interactions, accuracy assessed commercial volume CFD software, FLOW-3D. The FLOW-3D validated against experimental bub...

We analyze the stability of small bubbles in a closed system with fixed volume, temperature, and number of molecules. We show that there exists a minimum stable size of a bubble. Thus there exists a range of densities where no stable bubbles are allowed and the system has a homogeneous density which is lower than the coexistence density of the liquid. This becomes possible due to the finite liq...

In order to simulate the acoustic cavitation process of double-bubble coupling, based on fluid dynamics governing equation and volume fraction model, this paper proposes a three-dimensional finite element simulation model coupled ultrasonic in Fluent software, numerically simulates dynamic driven by wave. The nonlinear characteristics with double bubbles are studied evaluating variation field a...

In the present paper, the measurements of the bubble-point pressures and the liquid densities of refrigerant mixtures composed ofR-32, R-125 and/orR-143aarereportedfortemperaturesfrom 280to 320 Kin 10 Kintervals and for entire compositions. An experimental apparatus used is a magnetic densimeter coupled with a variable volume cell. Based on the measured bubble-point pressures, the optimization ...

Closure relations are presented for the lift coe.cient for ordered arrays of 2-D and 3-D bubbles at various bubble volume fractions. These were determined via lattice Boltzmann simulations of bubble rise in periodic boxes, where the bubbles were also subjected to shear. The single-bubble lift coe.cient, determined by low-shear computational experiments, varies in a systematic manner with the as...

We studied experimentally the dependence of light emission and phase space boundaries of air bubbles in water on the level of degassing down to low partial pressures of 15 mmHg. We found that the maximum obtainable light intensity increased monotonically by lowering the concentration of dissolved air in water. We also present a new technique to obtain the acoustic pressure (P(a)) and ambient ra...