Category Archives: Recirculation zone fluid mechanics

Recirculation zone fluid mechanics

Flow recirculation zones around one or many pairs of injection-extraction wells occur in many practical groundwater flow, reservoir engineering and geothermal engineering problems. Typical application examples are capture zone delineation, forced-gradient tracer tests for aquifer characterization, in-situ remediation of contaminated groundwater, thermogeological assessment of open-loop well-doublet schemes, seasonal heat storage and recovery, and cold fluid reinjection into produced geothermal reservoirs.

The purpose of this modelling exercise is to simulate steady-state flow patterns around a pair of injection and production wells which are supposed to inject back pumped water with the same flow rate. Problem dimensions and aquifer characteristics used in this tutorial are patterned following the mean characteristics of the carbonates Dogger geothermal reservoir layer which is a mildly meters deep hot aquifer in the Paris basin.

It represents the only operational low-enthalpy geothermal system in France since the 's. We will go through the following steps to build a simulation script modelling the steady-state flow patterns around one doublet in this geothermal reservoir:. Let's first specify the simple aquifer geometry which is a one layer model of m x m x 25m along each space dimension. Next, we set the number of grid cells along each direction.

Herein we choose a uniform grid spacing equal to 25m along X and Y directions in the horizontal plane. Next, let N to equal the number of grid cells or elements in the model.

To fullfill the need of internal compuattional tasks we add the uniform grid spacings, hxhyand hzalong the respective directions to the Grid structure. Additionally, we need to setup other few variables for the Grid structure such as, V the uniform cells volumeand K the tintrinsic permeability tensor. The MATLAB command ones 3,Nx,Ny,Nz constructs such an array with a unit values for all cells, and thus by multiplying it with a constant unit Darcy we obtain an isotropic and homogeneous distribution of the permeability data over the computational domain.

Next, we construct a cartesian grid G data structure from the domain extents and spacings. This will help to do the plotting commands more efficiently.

Experimental characterization of combustion in recirculation zone of double-stage swirl chamber

Before setting the flow rates we define some useful constants to convert between time units. Notice that by convention injection flow rates are positive and production ones are negrative.

Qw is the well rates array.

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It is null everywhere except at cell numbers where the wells are located. Finally, we setup the fluid properties by initializing a Fluid object named 'water' with user-defined constant density and viscosity properties equal to and respectively.

To simulate steady-state flow we simply call the Pressure solver.Laser Techniques for Fluid Mechanics pp Cite as. The application of various optical diagnostic methods, including the recently modified FIV method, allows detailed investigation of the special effervescent atomizer and flameholder assembly.

The ability of the atomizer to produce oscillating spray and heat release over a wide frequency range as well as its high sensitivity to small driving pressure fluctuation was demonstrated. This allows the use of the special effervescent type atomizer to suppress combustion instability almost completely. Hence, it can be mounted in the flameholder section of a typical ramjet combustor and assist in the suppression of its instabilities.

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Skip to main content. This service is more advanced with JavaScript available. Advertisement Hide. Fluid image velocimetry of flow in the recirculation zone of a bluff body stabilized and controlled burner. Authors Authors and affiliations B. Golovanevsky Y. Conference paper. This is a preview of subscription content, log in to check access.

Quenot, G. Google Scholar. Kowalewski, T. Levy, Y. Sveen, J. Golovanevsky 1 Y. Levy 1 1. Personalised recommendations. Cite paper How to cite?Jahnke, C. December 1, Fluids Eng. December ; 4 : — The flow field induced inside a cylindrical container by the rotation of the two end walls is described.

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Flow fields in a container of aspect ratio 2. For a range of ratios of the rotation rates of the top and bottom end walls and Reynolds numbers it is shown that ring vortices surrounding a columnar vortex core exist.

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Daniel T. Valentine Daniel T. Author and Article Information. Craig C. Dec4 : 5 pages. Published Online: December 1, Article history Received:. Issue Section:. Doedel, E.Engineering Stack Exchange is a question and answer site for professionals and students of engineering. It only takes a minute to sign up.

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If we place a obstacle in the fluid flow, fluid will be circulating behind the obstacle. What is this called? Generally the term 'wake' is used to describe any downstream disturbance to flow caused by an obstacle. Typically the wake will expand outwards in an approximate 'V' shape until it eventually dissipates into the general 'noise' of the flow whereas recirculation occurs is a reasonably well defined region immediately downstream of the obstacle.

Recirculation is a specific condition where the flow separates from the body of the obstacle. This creates a low pressure area immediately downstream which sucks fluid back into this region from the main flow with the net result of creating a circulating vortex or pair of vortices.

This condition creates marked increase in drag compared to situations where the flow remains attached to the surface. If flow separation is likely it is often better to deliberately induce turbulence early rather than have an abrupt separation of laminar flow.

This is a major and complex subject in fluid mechanics and the above should be considered an introduction rather than a comprehensive explanation. Sign up to join this community.

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The best answers are voted up and rise to the top. What is the difference between wake and recirculation region? Ask Question. Asked 4 years, 11 months ago. Active 4 years, 11 months ago. Viewed 8k times. This might be a wake or recirculation region.

What is the difference?

recirculation zone fluid mechanics

Improve this question. Do you mean "behind" instead of "begging"? The context of "wake" and "recirculation" suggest this. Active Oldest Votes. Improve this answer. Chris Johns Chris Johns Sign up or log in Sign up using Google.

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Featured on Meta. Related 4. Hot Network Questions. Question feed.May 22,what is difference between recirculation region, eddy field and vortex?

Experimental characterization of combustion in recirculation zone of double-stage swirl chamber

As tittle stated, the definition of recirculation region means the a stationary vortex, where the vortex does not move, it will become recirculation region. A moving vortex is a vortex, a stationary vortex is a recirculation region, am i right? Then comes to eddy, I always though eddy is vortex. Last edited by fruitkiwi; May 22, at May 22, May 23, A recirculation zone is a vortex and an eddy is a vortex.

Just like a tornado is a vortex. A stream can have an eddy field caused by rocks, and a recirculation zone too. The eddies flowing with the stream can affect the particles in the recirculation zone by running into the outer edges of the recirculation zone.

An eddy dissipates, but a recirculation zone does not. Originally Posted by mettler. May 28, I think these are all lose terms, and could describe different phenomena at different flow.

A "recirculating region" could be a stationary vortex as stated, but on the other hand we always call the unstationary velocity field at the corner of a "backward facing step" as recirculation region.

I think recirculating regions occur always attach to a wall due to pressure gradients. Vortex on the other hand is a general descriptive word for globally rotating field. Eddy, on the other hand, has a viscous origin. In other words, eddies generated by some sort of shear so they always has some vorticity.Skip to main content. Volume 15, Issue 8. No Access. David G. Tools Add to favorites Download citation Track citations.

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recirculation zone fluid mechanics

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recirculation zone fluid mechanics

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Investigation of flame behavior and dynamics prior to lean blowout in a combustor with varying mixedness of reactants for the early detection of lean blowout.Thanks for helping us catch any problems with articles on DeepDyve. We'll do our best to fix them. Check all that apply - Please note that only the first page is available if you have not selected a reading option after clicking "Read Article". Include any more information that will help us locate the issue and fix it faster for you.

The problem of the motion of a swirling flow in an axisymmetric channel with permeable walls is investigated numerically. Various flow regimes including those with the formation of recirculation zones are obtained. The problem of atomization of a powder by a swirling flow for the purpose of obtaining a finely dispersed mixture is considered. Particle concentration distributions in the flow are calculated, the formation of characteristic deposition zones is demonstrated, and the unsteady process of particle transfer is investigated with allowance for deposition on the lateral surface of the channel.

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recirculation zone fluid mechanics

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