DE102008036602A1 - Pipe for transporting flow medium, has multilayer pipe wall with wall structure made of elastic flexible sublayers, where transition between laminar and turbulent flows is produced by pipe, and is shifted to high Reynolds number - Google Patents

Abstract

The pipe has a multilayer pipe wall comprising a wall structure made of elastic flexible sublayers. A transition between a laminar flow and a turbulent flow is produced by the pipe, where the transition is shifted to a high Reynolds number. The sublayers of the wall structure are formed from outer firm frame (1), flexible middle layer (2) and a flexible inner layer (3). The inner layer comprises a high elasticity module than the middle layer, which is formed from a flexible fluid material. The inner layer is formed from a flexible material.

Description

The The invention relates to a pipe for transporting flowing media according to the preamble of claim 1.

Tube with a multilayer pipe wall are known. In such Pipes, the pipe wall has a layered structure of part different materials. For example, flexible pre-insulated ones multi-layer drinking water pipes known. Multilayer pipes are becoming increasingly common in wide-body aircraft for weight reasons installed. Safety aspects play a major role here.

The pamphlets DE 19504618 A1 and DE 29502265 U1 describe motor vehicle pipelines with diffusion-tight, frictional and flame-retardant layers. The publication DE 4309829 C2 describes a use of barrier plastics as strength carriers in motor vehicle pipelines.

The pamphlets DE 102004010340 B4 . DE 29712989 U1 . DE 102004056192 B4 and EP 0360758 B1 describe multi-layer pipes in whose layers fibers, minerals or resins contribute to the stability improvement. The publication DE 19926850 A1 describes pipelines with a multi-layer insulation.

The pamphlets US 3,161,385 and US 3,585,953 describe an optimized multi-layered construction of the pipe wall with respect to moving in fluid media body, such as ships or torpedoes.

at the flow of media in a pipe will cause pipe friction losses on. In order to minimize these pipe friction losses, are according to the state technology tubes with a smooth hydraulic inner surface used. These are made of correspondingly smooth materials and / or produced by special manufacturing processes.

Generally applies when operating a pipeline or a pipeline network that the energy required to drive a medium proportionally to the pressure loss occurring throughout the network. The pressure loss is the in the piping, fittings, fittings, etc. resulting pressure difference between two measuring points. This pressure difference has its cause in the friction called friction between the medium and the tube as well as the internal friction of the medium even.

The Size of the pipe friction depends on the Type of flow, flow velocity, the pipe diameter and the roughness of the pipe. Distinguish it the pipe friction losses for a laminar flow in a fundamental way of those who are in a turbulent Flow in the pipe occur.

The Boundary between laminar and turbulent flow becomes described by the so-called Reynolds number Re. The Reynolds number depends on the average flow velocity v of the medium and a characteristic length L and the kinematic viscosity of the flowing medium ν. For pipe flows, L corresponds to the clear diameter D of the pipe. Empirically, it turns out that at a value of Re = 2000 the laminar flow in the pipe into the turbulent flow turns. This sets particularly fast within valves and branches.

At the transition from laminar to turbulent flow, the friction loss increases strong in the pipe. For hydrodynamically smooth tubes this is Increase about 60%. At an increase in the Reynolds number to a value of Re = 4000 is the increase in the pipeline losses Compared to the laminar flow at from the state of Technik known tubes already 150% and is thus exceedingly considerably.

The laminar flow of a medium at a low Reynolds number within a pipe thus proves to be particularly low loss and effective. A disadvantage of this flow, however, is that the laminar flow always with relative low flow rates is connected.

It Thus, there is the problem underlying the invention, a pipe specify the boundary between laminar flow and turbulent flow to larger ones Flow rates are shifted and thus the friction losses and the necessary energy consumption for the flow of media can be minimized.

The Task is with a pipe to transport flowing media solved with the features of claim 1. The dependent claims contain expedient or advantageous embodiments of the tube according to the invention.

To solve the problem is used on a pipe for transporting media flowing with a multi-layer pipe wall. This tube is inventively characterized in that the multi-layer pipe wall has a wall structure of elastically resilient sub-layers, wherein ver through the pipe formed with this wall structure to a higher Reynolds number schobener transition between a laminar flow and a turbulent flow can be generated.

Of the So formed wall construction causes locally increased pressures within the medium by compressing the sublayers absorbed and thus reduced. This will be the formation from whirling and thus ultimately the envelope of laminar to turbulent Flow is prevented. This envelope is compared to a conventional pipe thus only at higher flow velocities, d. H. at larger Reynolds numbers, instead. About that In addition, this design of the wall structure also causes a reduction of Vortex formation in turbulent flowing medium, so too in a turbulent flow, the friction losses of Flow are significantly minimized.

The Partial layers of the wall structure exist in a functional Embodiment of an outer solid Basic framework, a resilient middle class and a compliant inner layer.

The outer solid framework forms a stable outer shell of the tube, the middle layer and the inner layer cause the mentioned reduction of turbulence occurring in the pipe.

It is advantageous if the inner layer is one compared to the middle layer has higher modulus of elasticity. At a particularly advantageous embodiment the middle layer consists of a soft to liquid Material, while the inner layer of a soft though solid material is formed. Such a design of the layer structure ensures a particularly good local pressure reduction.

at Another embodiment includes the inner layer solid particles. This stabilizes the inner layer on the one hand. On the other hand, it has been shown that such a modification of the Inner layer contribute to an improved function of the inner layer can.

at a first embodiment, both the inner layer, as well as the middle layer made of the same material, wherein the material has a different density depending on the layer having.

at In a second embodiment, the middle layer and the inner layer formed of different materials.

The pipe according to the invention will be explained in more detail below with reference to exemplary embodiments. For clarification, the attached serves 1 , This shows an exemplary tube with a multilayer pipe wall in a longitudinal and a cross section.

The outer layer of the multilayer pipe wall is replaced by a skeleton 1 educated. In the simplest embodiment, the basic framework is a sufficiently resistant, in the form of a hollow cylinder, sufficiently resilient, if necessary within certain limits elastically bendable and be laid along a curved path body. This can, as required, consist of a metallic material, a concrete, a plastic, but also a glass or a ceramic.

at Another embodiment consists of the skeleton made of a composite of a reinforcement and a reinforcement surrounding cover material or a fiber composite.

The The basic structure simultaneously forms the outer one Tubular casing with the usual sealing surfaces, Connecting pieces, connecting threads and the like connection means. These are designed so that the pipe can be easily used the known installation method can be mounted.

The basic structure 1 inside a middle layer closes 2 and an inner layer 3 one. The middle class 2 and the inner layer 3 consist of flexible, elastically deformable or soft materials. The layers can either be made of the same material, wherein the density of the inner layer 3 greater than the density of the middle class 2 is. In another embodiment, both layers are made of different materials.

expedient is a pliant, soft middle layer in combination with a through a larger modulus of elasticity excellent inner layer. As a middle class come in particular Coverings of a highly viscous, partially liquid or gelatinous material. The liquid or If necessary, the gel is in a tube-like container locked in.

The Middle layer can also consist of a solid material. Therefor Elastomers, rubber or rubber materials are considered. Usable are both compact material layers as well loosened material structures, such as foams or sponges.

The inner layer 3 consists of a solid, elastic material with a greater modulus of elasticity and / or greater density than the middle layer. For the inner layer in particular elastomers, rubber or rubber materials can be used.

To increase the strength of the interior Layer against thermal or chemical loads in one embodiment, a coating is provided. The coating may be in the form of a metallization or a plastic covering.

at In another embodiment, the inner layer is embedded Particles on. These stabilize the structure of the inner layer.

For improved adhesion of the middle layer to the backbone are in an expedient embodiment on the inside of the skeleton formations or Roughing provided with which the contact between middle class and backbone made particularly resistant can be.

One Pipe with the features described here allows a clear shift of the transition point between laminar and turbulent flow. Experiments have shown that the Reynolds number of Re. associated with this envelope = 2000 increase to Re = 4000. This means in particular special, that the medium flowing in the tube at one compared flow rate doubled to conventional tubes still shows a laminar flow behavior. This beats especially in one at this Reynolds number decreased by 40% Loss of friction down.

Further Embodiments emerge from the subclaims or by expert action.

1

backbone

2

middle class

3

inner layer

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19504618 A1 [0003]
• - DE 29502265 U1 [0003]
• - DE 4309829 C2 [0003]
• DE 102004010340 B4 [0004]
• - DE 29712989 U1 [0004]
• DE 102004056192 B4 [0004]
• EP 0360758 B1 [0004]
• - DE 19926850 A1 [0004]
• - US 3161385 [0005]
• US 3585953 [0005]

Claims (7)

Pipe for the transport of flowing media with a multi-layer pipe wall, characterized in that the multi-layer pipe wall has a wall structure made of elastically resilient sub-layers, which can be generated by the tube formed with this wall structure shifted to a higher Reynolds number transition between a laminar flow and a turbulent flow , Pipe according to claim 1, characterized in that the sub-layers of the wall structure of an outer solid skeleton ( 1 ), a resilient middle class ( 2 ) and a resilient inner layer ( 3 ) are formed. Pipe according to claim 1 or 2, characterized in that the inner layer ( 3 ) one compared to the middle class ( 2 ) has higher modulus of elasticity. Pipe according to one of the preceding claims, characterized in that the middle layer ( 2 ) of a soft to liquid material and the inner layer ( 3 ) is formed of a soft material. Pipe according to one of the preceding claims, characterized in that the inner layer ( 3 ) contains solid particles. Pipe according to one of the preceding claims, characterized in that the middle layer ( 2 ) and the inner layer ( 3 ) are formed of a same material, wherein the material has a different from layer to layer density. Pipe according to one of claims 1 to 5, characterized in that the middle layer ( 2 ) and the inner layer ( 1 ) are formed of different materials.