Bubblers and Their Effects on the Energy Conversion Efficiency of Smoke Pipes

Bubblers are a staple of the modern smoker’s collection, offering water pipe function and filtration with the added benefit of being portable and easy to use. Bubblers come in a number of styles, including the popular hammer bubbler and mini bubblers, all crafted from borosilicate glass for added strength and durability. Whether you’re searching for a new piece or looking to add to your existing collection, you’re sure to find the perfect bubbler here at Smoke Cartel.

Bubbles are naturally self-oscillating, and their oscillation can be efficiently converted to mechanical energy. However, the mechanical energy conversion efficiency of wholesale bubblers is strongly dependent on details of the device geometry such as the gap thickness, the bubble size and the inlet-hole diameter as well as the fluid viscosity and bubble oscillation frequency. Moreover, the bubbler energy conversion efficiency also depends on the rate of mechanical energy dissipation due to viscous forces.

To investigate these effects we carried out simulations using COSMOL Multiphysics, which uses the arbitrary Lagrangian Eulerian (ALE) moving mesh technique to resolve the fluid-bubble interface. The ALE approach provides exact body-fitted mesh lines for the bubble interface and significantly alleviates the need for expensive remeshing and interpolation in conventional Lagrangian Eulerian (LE) methods.

We modeled the behavior of a single bubble in a Hele-Shaw channel at constant mercury and air inlet pressures. As the bubble grows and shrinks, it induces a harmonic oscillation in the Hele-Shaw flow, which is driven by the difference between the mercury and air pressure. The bubble oscillation period increases with increasing gap width and decreases with decreasing air inlet pressure. The Hele-Shaw flow is highly sensitive to the variation in the gas pressures, and it is possible to generate a stable oscillation with frequencies as high as 2 kHz.

The bubbler’s power density increases with increasing the bias voltage and oscillation frequency. At these conditions, the bubbler can generate an average of 10 kWm-2 per unit volume. This is an order of magnitude higher than the predicted maximum power density based on the REWOD method alone2.

The lateral position of a bubble in the Hele-Shaw channel varies with its diameter. For bubbles with diameters larger than half of the channel width, they move towards the centerline, while those with smaller diameters close to the wall of the channel. This is a result of the unequal force field exerted on the bubble by the symmetric velocity profile and stronger deformation-induced lift from the fluid flow at low Ca.

The results of the simulations provide important insights for designing new devices to efficiently convert mechanical energy from human, machine or building movement into electrical energy. This can be achieved by maximizing the amount of time that the bubble is in contact with the Hele-Shaw flow, while minimizing the energy dissipation due to friction and other mechanisms. Further, the design principles can be applied to a wide variety of mechanical sources with various forces, displacements and frequencies.