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Why Plug Flow Is Better Than Completely Mixed Flow

What is the difference between plug flow and laminar flow? Are they both the same?

Not at all. True plug flow does not exist. This is an idealised condition where fluid passes along a conduit (a pipe say) as if it were a solid plug that moves like a piston in a cylinder. Fluids do not do this. At the wall there is zero velocity and in the centre of the pipe the velocity is at a maximum. There is a velocity gradient from wall to centre. The flow in a pipe can be laminar (Reynolds number, Re, below 2300), in which case radial mixing does not occur to fully developed turbulent above Re = 10,000 in which radial mixing occurs. The nearest approximation to plug flow I can think of is passage of a fluid through a packed bed where the front can be made to remain reasonably flat but generally the term plug flow is misleading.

What is a mixed flow reactor?

um Push flow reactor is also called piston flow or tubular reactor To push for chemical reaction flow form of reactor in the reactor through the reactor with liquid materials particles in the same order The order of the particles within the device remains the same, the residence time is equal to the theory of residence time flow form and the aspect ratio of a rectangular approximation in the pool fluid flow, reduce or eliminate the longitudinal dispersion effect Is one of the most common form in the process of water treatment

What is a plug flow reactor?

A reactor is said to have a plug flow whenAll the molecules in the reactor have the same residence time or spend the same time inside the reactors .This givesrise to the following characteristics to the reactor :Infinite mixing in radial direction .Zero mixing in axial directionFlat velocity profile

Why is the volume of a plug flow reactor always lower than the continuous stirred tank reactor?

Well, from what I can understand from the articles on this subject, available on the web and as explained under item 3 on page 4; in a (PFR) - (packed) plug flow reactor, perhaps the mixing is not so homogeneous about the axis of the stirred mixture and this portion is fed back, for further mixing, as compared with the CSTR reactor.My take is that it is relative and is determined by the composition, type and material characteristics and what the final output should be - either for use and / or further processing ? a better day !

What is the advantage of minimum mixing in plug flow reactor?

For a first order or higher chemical reaction, the reaction rate is proportional (or higher) to the concentration. A plug flow reactor maintains the highest possible concentration as opposed to a stirred-tank reactor. Any longitudinal mixing tends o decrease the concentration.

Where can I find a top plug flow reactor system in Mumbai?

In the chemical industry whenever an exothermic or explosive reaction is needed to be carried out through the conventional way then in that case our manufactured Plug Flow Reactor is widely utilized. They also ensure the safety of the equipments beside the uniform heat transfer. Their manufactured compact reactor possesses all the characteristics of heat transfer, static mixing and reaction engineering. In this equipment the surfaces for heat transfer are positioned in a way so that mixing as well as the heat transfer turn out to be complementary to each other.Order Plug flow reactor system from Rufouz hitek engineers pvt ltd with affordable cost.

Which will give higher conversion- a PFR (plug flow reactor) or a fixed bed reactor? And why?

PFR is one of the ideal reactors which provides higher conversion. In an ideal PFR, there is no mixing along the axial length although there would be lateral mixing of the reactants along the radial direction.PFR is a reactor where the concentration of the reactant is maintained high as it flows from one end to another. Hence PFR is mostly prefered for positive order (n>1) reactions. When the rate of reaction is maintained higher, volume of the reactor would be greatly reduced., thereby minimizing the total fixed and variable costs.A packed bed reactor (PBR) is prefered for heterogenous reactions, where the solid-fluid contact greatly influences the rate of reaction. A PBR is a cylindrical vessel filled with solids ( a reactant). The other reactant is allowed to enter in to the bed through the bottom. In the case of PBR, there are conditions which makes the reactor a non-ideal. Channeling and dead zones are the conditions which leads to non ideal reactor conditions. These conditions are more prevalent in a PBR. A non- ideal reactor conversion will always be less than an ideal reactor.Thank You:)

What is a fully developed laminar and turbulent flow?

Fully developed flows refer to spatial in variance of the flow in study along the direction of flow, ie. no change in properties along the direction of flow. Hydro dynamically, this implies to the  first derivative of velocity along the flow direction to be zero. This is achieved by the pressure gradients which drive the flow ( accelerate the flow) being equally balanced by the shear forces ( fictional force), that retard the flow. This is true in general for any flow whether laminar or turbulent.The main difference between laminar and turbulent flows lies in the complexity of flow patterns, which are far more complicated in turbulence due to seemingly random distribution of velocities in time, accompanied by large number of vortices of various sizes present all the time. Hence, when the flow is laminar, we have pressure forces being balanced by viscous forces, which are  functions of mean velocity gradients and related through viscosity. For most fluids having low viscosity like air, these are given by Newton's law. For steady pipe flows, solving the momentum equation ( Navier strokes equation) gives a parabolic velocity profile across the radius.When the flow is turbulent, the effective shear force is not related to only mean velocity gradients but dominated by a much larger term known as the Reynolds stress, which in simple terms is related to square of the turbulent velocity fluctuations. Thus, when we deal with fully developed turbulent flows, the time averaged momentum equation has an additional term which plays the same role as an enhanced viscosity. This results in the velocity profile to be different from laminar flows.Many answers have listed that the gradients for fully developed turbulent flows are steeper at the walls, followed by flattening or plug flow like profile away from the walls or boundaries. This is a result of the enhanced viscosity. Higher viscosity results in more smoothening out of velocity, thus having a " flat" profile away from the walls.

Why does a combustion engine need air mixed with gasoline?

If the whole point of a choke is to prevent air flow in the initial start up to give the engine a rich mixture, why doesn't it just continue to run off of this, why when started, do we need to air air to the fuel?