Hydraulic process

If we consider only chemical and hydraulic processes, the equations (1) for specific discharge q and solute mass flux relative to the solution Jd, in terms of gradients of pressure p and salt mass fraction uts reduce to [1]... 

The power of mixing is simply power dissipation. In any hydraulic process, power or energy is dissipated through friction. Thus, the power of mixing in any hydraulic mixer can be determined if the fluid friction hf can be calculated. The product of rate of flow Q and specihc weight 7 is weight (force) per unit time. If this product is multiplied by hf the result is power. Thus,... 

Reverse osmosis is a cross-flow process and, as in any dynamic hydraulic process, the fluid adjacent to the membrane moves slower than the main stream. While the main stream flow may be turbulent, the layer next to the membrane surface is laminar. This thin, laminar flow film is called the boundary layer. When water permeates through the membrane, nearly all of the salt remains behind in the boundary layer next to the membrane. The salt must then diffuse across the boundary layer and back into the bulk stream. This results in a boundary layer with a salt concentration which is more concentrated than the bulk stream. The effect has been termed concentration polarization, and it is defined by the following equation ... 

Variables which affect the hydraulic process are generally the same ones which affected the pneumatic process with some exceptions. However, the relative importance and optimum values of these variables are quite different in a number of cases. 

Process temperatures. The process temperature control is less critical in the hydraulic process than in the pneumatic system. 

Wax-coating temperature. Wax-coating temperatures do not appear to be so critical in the hydraulic process. Good results are obtained when the wax-coating temperature is 155-180°F. 

The second hydraulic process that is included in the fracture is the variation of capillary pressure caused by changes in the aperture. According to Kelvin s law the capillary pressure necessary to desaturate a fracture is given by ... 

In principle all the THMC processes may be involved in the geotechnical and geo-environmental problems. However, to simplify the problem for solution, only the major processes are considered for a particular problem. For example, the dam foundation problems are practically dominated by the coupled HM processes. The objectives of the solution are the interactions between the foundation stresses and deformation (the mechanical process), and the seepage pressure and flow rate (hydraulic process). Only in some special cases the thermal and/or chemical processes may also be involved, say, for dams built in cold region or on rock foundation of high solubility. 

Abstract To better understand the coupling of thermal (T), hydraulic (H) and mechanical (M) processes (T-H-M processes) and their influence on the system behaviour, models allowing T-H-M coupling are developed. These models allow simulations in the near-field of the system. Such a model has been developed within the simulator RockFlow/RockMech. This paper concentrates on the thermal and hydraulic processes. For those processes, the material parameters and state variables are highly non-linear and mostly functions of temperature, saturation and pressure. This paper shows how these dependencies are formulated mathematically and are implemented into RockFlow/RockMech. The implementation allows phase changes between the fluid phases (gas and liquid) to occur explicitly. The model allows the simulation of very low permeability clays with high capillary pressures. An example for code validation is shown, where low permeability clay is desaturated, lastly, current work on the calculations performed in the near field study (BMTl) of the DECOY ALEX III project is outlined. 

On the other hand, the coupled processes in the far field are described in this chapter based on the results of the near field analysis. Assuming that mechanical behavior and unsaturated flow are negligible for regional groundwater flow system, only coupled thermal and hydraulic processes in saturated zone are considered. Governing equation... 

Strictly speaking, the governing equations for the near field are those of THAMES. However, the assumption can be permitted because the Equation (1) and the Equation (3). are almost same as the governing equations of THAMES in thermal and hydraulic processes. 

The present-day shelves and their sediments reflect conditions of the Last Glacial period and probably the former low sea level stands at depths of over 100 m. Large bodies of wind-blown, river-transported, and nearshore marine sand that accumulated on the Pleistocene coastal plains, beaches, and river mouths, and were drowned by the Holocene rapid sea-level rise. These sediments are only partially covered by modem sediments, resulting in very complex shelf morphologies. A (near-) equilibrium state between hydraulic processes and sediment distribution in which the shelf has been completely covered... 

In-depth computer analyses of thermal and hydraulic processes should be performed. 

Degradation of natural circulation during shutdown conditions, mainly in WWER reactors, should be accounted for adequately when estimating the shutdown risk in PSA studies. Detailed computer analyses of thermal and hydraulic processes should be carried out to show whether and at what time these processes could lead to core damage. 

Beebe is partieularly known for hydraulics by his 1917 Report written jointly with Ross Riegel (1881-1966). This woik, made for the Miami Conservancy District, deals with hydraulic jiunps both in prismatic and in expanding stilling basins. Until then, few experimental works were conducted on this important free surface phenomenon. The main works further were conducted for either small supercritical approach flow Froude numbers, or for extremely small approach flow depths, resulting in scale effects. The results were not readily available but demonstrated that these complex hydraulic processes were amenable by hydraulic modeling. Beebe was also involved in the 1930s in the control of debris flow at Mount Shasta In 1924, a large mud flow had deposited almost one million m of debris which muddied the Sacramento River. Beebe outlined means to coimter future similar scenarios, which had also occurred in the 19 century, and were a constant threat to the Sacramento Valley. 

Well performed laboratory deformation tests were used to develop the constitutive equations which are prerequisites for the computer analysis of the coupled thermal, mechanical, and hydraulic processes in rock and for the prediction of the long-term behaviour of a rock formation especially for underground repositories or storage caverns (e.g. storage of gas and oil). 

The calculational models should allow calculation of the fuel pin characterisation for the End of Equilibrium Cycle Core Loading Scheme and during the transient as well as the transient thermal and hydraulics processes in the reactor and in the primary circuit taking into account the sodium boiling. The models should include multichannel representations of the core (12-30 channels), with appropriate models of the out- and inlet plenum and the IHX, or prespecified in-/outlet boundary conditions (pressure and temperature). 

Monitor. Equipment for directing a high-pressure (2 MPa) jet of water against a clay face in the hydraulic process of winning china clay. 

Vhyd is the advection velocity due to hydraulic processes, is the diffusion velocity (expressed in terms of the first Pick s law in the above relation, A represents the aquifer section), Vion is the electromigration velocity, and v op is the electroosmotic flow velocity. The last two terms depend on the strength of the applied electric field, AF/AL. 

The hydraulic process is currently producing commercial diamonds up to 6 mm, weighing 2 carats (0.4 g) in hydraulic presses such as the one shown in Fig. 12.5. Micron-size crystals are produced in a few minutes producing a two-carat crystal may take several weeks. Typical crystals are shown in Fig. 12.6. Even larger crystals, up to 17 mm, have recently been announced by de Beers in South Africa and others. Research in high-pressure synthesis is continuing unabated in an effort to lower production costs and produce still-larger crystals. 

J. Recio and H. Oumeraci, A numerical study on the hydraulic processes associated with the instability of GSC-structures using a VOF-RANS model, Leichtweiss-Institute for Hydraulic Engineering and Water Resources, LWI Report No. 941 (2006). J. Recio and H. Oumeraci, Processes affecting the stability of revetments made with geotextile sand containers, Proc. Int. Gonf. Coastal Engineering, ICCE 2006, San Diego, USA (2006). 

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