To investigate the flow characteristics of a novel dual-slot overflow channel, research approach integrating physical experiments and numerical simulations was adopted. A three-dimensional model channel developed, employing RNG k-ε turbulence VOF two-phase to optimize simulation high-low field. Physical were conducted verify analyze hydraulic including longitudinal water surface profile patterns. The results aligned well with test results. By analyzing field counterflow spillway, at both...

The gas-film-lubricated mechanical face seal is a combined hydrodynamic and hydrostatic with positive leakage. Up to now, it has been widely accepted by end, users builders of high-speed turbo compressors. groove technology on the sealing seat one core technologies dry gas seals. This article presents patented herringbone spiral-grooved seal. Its one-dimensional analytical solution two-dimensional numerical methods for gas-film pressure distribution are presented. more than 200 seals...

Total dissolved gas (TDG) supersaturation can cause potentially fatal Gas Bubble Disease (GBD) in fish and is recognized for its severe environmental impact high‐dam operation conditions. The generation of supersaturated TDG high‐head hydropower project substantially different from middle‐ or low‐head projects that have been previously studied. Although the mechanics a plunge pool are clearly three‐dimensional (3D), there great challenges difficulties 3D simulation projects. Toward this end,...

The oil-film-lubricated mechanical face seal is a kind of pure hydrodynamic lubricated noncontacting with zero leakage. On the basis systematic theoretical analyses, design calculation formulas under zero-leakage condition for seals different spiral groove patterns, including double-row grooves such as splay pattern and single-row grooves, are derived. effects geometry number balance ratio, spring force, rotating speed, differential pressure on performance discussed in detail. Finally,...

Aerated flows are characterized by complex hydrodynamics and mass-transfer processes. As a Lagrangian method, smoothed particle (SPH) has significant advantage in tracking the air-water interface turbulent flows. This paper presents application of an SPH method to investigate reaeration over stepped spillways. In entrainment dissolved oxygen (DO) is studied using multiphase mass transfer for reaeration. The numerical results compared with data from Chanson DO Cheng. simulation show that...

ABSTRACTThe release of supersaturated total dissolved gas (STDG) from dams has been linked to the development bubble disease, which can ultimately result in death fish. In order minimize impact STDG on aquatic ecology, effect aeration mass transfer at air-liquid interface is taken into account. This paper selects four commonly used aerators carry out indoor tower experiments under different conditions (aeration aperture, water depth, and volume), exploring that efficiently promote release....

The oil-film-lubricated mechanical face seal described here is a hydrodynamically lubricated, noncontacting, with zero leakage. On the basis of systematic theoretical analyses, research on design methods, and experimental investigations, many field applications have been made. investigations include test rig development; long-time high-speed running tests; frequent start-up shut-down measurements leakage, temperature, characteristics self-circulating screw pump; observation, measurement,...

Supersaturation of total dissolved gas (TDG) is a common occurrence in high dams during the spill process, which can lead to fish bubble disease and threaten aquatic organisms. As result, many scholars have taken keen interest this issue. Research into gas-liquid mass transfer mechanism has improved accuracy TDG prediction models. This article investigates factors affecting dissipation through laboratory experiments. Especially, coefficient across interface based on slip penetration model...

Abstract Supersaturation of dissolved oxygen (DO) and total gas (TDG) is generated by high dam discharge, excess production in photosynthesis increasing temperature water, which may directly lead to fish suffering from ‘gas bubble disease’ or death. In this paper, under a series experimental aeration conditions standing it was concluded that had positively promoting effect on releases supersaturated DO TDG, while aperture depth inhibitory effects them. For single factor analysis, the...

Supersaturation of total dissolved gas (TDG) is mainly produced by high dam discharge, excess oxygen production plant photosynthesis, and a sharp increase in water temperature, which may directly lead to fish aquatic organisms suffering from “gas bubble disease” (GBD) or death. Aeration was one the methods used solve dissipation supersaturated TDG. In this paper, aeration had an obvious promotion effect on For calculation analysis TDG coefficient, rate proportional coefficient promoting it,...

Abstract Supersaturated total dissolved gas generation in rivers poses great harm to aquatic organisms. Thirty groups of supersaturated TDG dissipation experiments with aeration were carried out three different types water depth. These results showed that the reduced proportion aperture was 35.51% from 215 260 mm, rate decreased by 34.94% 1.0 5.0 m3/h, whereas depth increased 16.93% 0.4 1.2 m. And mm and m, variations coefficients 86.26, 23.74 −5.39%, respectively. A quantitative...