CN2410613Y - Double helical spring heat-transfer strengthening pipe - Google Patents

Abstract

The utility model relates to a double helical spring heat-transfer strengthening pipe, composed of a metal pipe and a double helical spring which is inserted in the metal pipe. Metal wire is wound into a small spring, and then the small spring is wound into a small spring again along a spring helical line to form the double helical spring. The utility model can be used for the heat-transfer strengthening of laminar flow and turbulent flow, the inner and the outer parts of the pipe, the pipes with a minor diameter and a major diameter and circular and non circular section pipes. With simple processing method, the utility model does not need expensive special equipment and can easily make the product produced serially.

Description

The heat conduction reinforced pipe of double-helix spring

The utility model relates to the heat conduction reinforced pipe of a kind of double-helix spring, belongs to heat conduction reinforced technology and field of heat exchangers

A large amount of heat transfer unit (HTU)s and high-performance heat exchanger are used to fields such as power, oil, chemical industry, metallurgy, Aero-Space.Therefore wherein the efficient of heat conduction reinforced device is the research field that engineering circle is very paid attention to cutting down the consumption of energy and equipment investment plays an important role, and the invention of the heat conduction reinforced device of existing dozens or even hundreds of kind.But the popular feature of these intensifying devices is: destroyed original velocity field characteristic, thereby flow resistance and power consumption increase significantly heat conduction reinforced the time; In addition, the complicated processing method of intensifying device and expensive processing charges are restricting its extensive use in engineering.

Volume in " heat exchanger " that hydrocarbon in 1988 processing publishing house publishes, the inner fin enhanced tube of 34-38 page or leaf record (Fig. 1 a) is characterized in: tube wall is processed with fin, and fin and pipe are an integral body or two splits, two kinds of materials can be identical also can difference.The strengthening mechanism of interior finned tube is: increase heat transfer area.But because the size of inner fin is bigger, the fluid velocity field goes to pot seriously, and resistance is big during operation.In addition, Fu Za inner fin shape has increased considerably difficulty of processing and expense.

The lap-ups silk reinforced element (patent No.: be to make axis 93217669.0), and other several one metal wires are turned to column type filament (Fig. 1 b) by certain rule with several one metal wires.Its strengthening mechanism is: make tube fluid produce the superimposed 3 D complex of radial displacement and spiral flow under low speed and flow, strengthen the heat exchange effect to play.But flow just because of the 3 D complex that the lap-ups silk produces, changed original flow field characteristic, the resistance increase is very obvious in the time of heat conduction reinforced.

Must the hair shape reinforced element (patent No.: be that filament is fixed on (Fig. 1 c) on the support that is in the tubular axis heart 98202045.7), reach the purpose of enhance fluid and conduit wall heat exchange by the heat exchange between reinforcement channel center's regional fluid and the tube wall.But the big speed fluid of tube hub stream the increase that wire and support can bring resistance, and its processing and difficult arrangement are restricting and are producing in enormous quantities.

Interior wing spring wire enhanced tube is the metal spring silk that inserts less diameter in internally finned tube, and spring wire closely contacts (Fig. 1 d) with tube wall.Spring wire plays the partial action of rib, strengthens radially streaming of near wall region fluid simultaneously.The intensifying method that this dependence is streamed will inevitably cause resistance to increase substantially, and has caused bigger difficulty of processing and expense.

The purpose of this utility model is the heat conduction reinforced pipe of a kind of double-helix spring of design, according to up-to-date heat convection mechanism, improves the structure of existing heat conduction reinforced element, makes heat conduction reinforced element heat transfer efficiency height, is easy to again make.

The utility model designs the heat conduction reinforced pipe of a kind of double-helix spring, form by metal tube and double-helix spring, double-helix spring inserts in the metal tube, double-helix spring is to be wound in little spring by wire, be wound in little spring once more and make along helical line of spring by little spring again, its size relationship satisfies:

d＝0.02～0.06D

D _s＝0.1～0.4D L _s＝2～10d

D _d=D-D _sL _d=1.5～4D _sIn the following formula, D is the diameter of enhanced tube, and d twines the used diameter wiry of little spring, D _sBe the little spring diameter that twines, L _sBe little spring pitch, D _dBe big spring diameter, L _dBe big spring pitch.

The heat conduction reinforced pipe of double-helix spring of the utility model design has following characteristics:

What 1, adopt is the high-thermal conductive metal silk of fine diameter.

2, filling rate wiry is lower, and the amplitude that flow resistance increases is less.

3, the mechanism of Qiang Huaing is to improve the heat conductivility of heat transfer space, changes little to original flow field characteristic.The coefficient of heat transfer can

To improve several times and even tens times, correspondingly much smaller (occurrence depends on fluid media (medium) in the increase of power consumption

Kind and parameter such as speed).

4, be applicable to Re scope (laminar flow and turbulent flow) widely.

5, be applicable in the pipe and the outer reinforcement of pipe.

6, be applicable to the heat conduction reinforced of cross section, non-garden pipe.

7, can realize reinforcement than the interior heat-transfer pipe of major diameter scope (10 millimeters to 200 millimeters).

8, the processing method simple possible of double-helix spring does not need expensive special equipment.

Description of drawings:

Fig. 1 is the structural representation of reinforced element in the prior art, and among Fig. 1, a is an inner fin, and b is the lap-ups silk, and c is a palpus hair shape, and d is a spring wire.

Fig. 2 strengthens heat convection mechanism schematic diagram for intraductal heat transfer.

Fig. 3 is the little spring structural representation.

Fig. 4 is the double-helix spring structural representation.

Fig. 5 is the enhanced tube structural representation of the utility model design.

Below in conjunction with accompanying drawing, introduce content of the present utility model in detail.

Among Fig. 5, the 1st, big spring, the 2nd, enhanced tube.

The heat conduction reinforced pipe of double-helix spring of the utility model design, its manufacturing process is as follows:

1, adopt the wire (copper wire, iron wire and stainless steel wire etc.) of high thermal conductivity, diameter d satisfies:

D=0.02～0.06D, wherein D is the diameter of enhanced tube.

2, at first wire is wound in spring (conveniently being called little spring for expressing), little spring diameter D as Fig. 3 _sWith pitch L _sSatisfy: D _s=0.1～0.4D; L _s=2～10d.

3, spring that will process above is wound in spring (conveniently be called big spring for expressing, thereby whole element being referred to as double-helix spring, as Fig. 4), big spring diameter D once more along helical line of spring _dWith pitch L _d, satisfy: D _d=D-D _sL _d=1.5～4D _s

4, by the specific purpose tool tool double-helix spring is inserted (as Fig. 5) in the metal tube.

5, owing to self elastic reaction, double-helix spring closely contacts with the inner surface of metal tube.

6, in order to reduce thermal contact resistance and to improve contact strength, can adopt soldering tech between double-helix spring and the metal tube surface.Require lower enhanced tube for weld strength, can tumble in one deck tin-lead solder on the surface of spring wire and metal tube, heat at the double-helix spring suit with after inserting again and realize solder: the enhanced tube of having relatively high expectations for weld strength can adopt the solder brazing technology.

7, metal spring is entwined along oval or other spiral path and can realizes the heat conduction reinforced of elliptical tube or other cross section, non-garden pipe.

Convection heat transfer intensity is decided by the convection current performance of the heat conductivility and the fluid of heat transfer space, and wherein heat conduction is the basis, and convection current is a necessary condition; Any heat of passing to the tube hub fluid by tube wall must at first rely on fluid heat conduction to pass to the tube hub zone, passes to the fluid main flow by convection current then; Low velocity fluid (highly being the zone of H among Fig. 2) near the wall place mainly is to play conductive force, and it is taken away a little less than the ability of heat; High-speed fluid (highly being the zone of D among Fig. 2) away from wall mainly plays convection action (taking away heat).

Simultaneously, the fluid velocity in D district is big, and is big with the temperature difference of tube wall face, thereby has the bigger ability of taking away heat with respect to the H district; Yet, although the convection current ability of D district fluid strong (speed is big), because the heat of this place's fluid removal all must rely on heat conduction to pass through the H district.Therefore, the heat conductivility difference in H district must become the bottleneck of whole heat convection.During for H/D=0.5, if H district fluid thermal conductivity factor is doubled, the D district is constant, calculates the coefficient of heat transfer and improves 80%; Opposite D district fluid thermal conductivity factor doubles, and the H district is constant, and the coefficient of heat transfer only improves 10%.

The heat conduction reinforced low heat conductivity energy that solves H district fluid just of double-helix spring has improved the heat conductivility of nearly wall place (low velocity district) heat transfer space significantly, rather than traditional increase heat transfer area.And because the speed of diameter wiry and fluid is little, it is faint streaming resistance.

Thermal conductivity factor wiry exceeds hundreds of even thousands of times than fluid media (medium) usually, and therefore the heat conductivility of the heat transfer space of less wire filling rate has been improved several times to tens times (height of describing with point among Fig. 2 is the zone of H) greatly.Thereby with traditional rib theoretical different be that effect wiry is not the heat convection ability that has improved H district, but by improving capacity of heat transmission raising D district, H district heat convection ability.For laminar flow, the value of H/D generally gets 1～3, and convection transfer rate was to become in proportion to increase with resistance coefficient substantially when theory showed low velocity with calculating.Convection transfer rate can increase by 2 to 20 times, and power consumption only increases by 1.4 to 3 times.

Strengthen for the turbulent convection heat exchange, conventional method is to destroy as far as possible or the attenuated layer laminar boundary layer, but this method can bring pressure drop sharply to raise.On the contrary, the fluid at nearly wall place that had stagnation of double-helix spring, thereby increased speed and temperature boundary layer thickness.But because the increasing substantially of heat conductivility in the boundary layer that this thickness has increased, bulk convection heat exchange property improvement degree is considerable; In addition, although exist fluid flow-disturbing resistance wiry in the boundary layer, because the increase of boundary layer thickness makes the radial velocity gradient reduce, the fluid-pressure drop increasing degree is not very big.For turbulent flow, the value of H/D generally gets 0.25～0.5, corresponding the reducing of the big more H/D of Re number in the pipe.

Claims (1)

1, the heat conduction reinforced pipe of a kind of double-helix spring, it is characterized in that, this enhanced tube is made up of metal tube and double-helix spring, described double-helix spring inserts in the metal tube, described double-helix spring is to be wound in little spring by wire, be wound in little spring once more and make along helical line of spring by little spring again, its size relationship satisfies:

d＝0.02～0.06D

D _s＝0.1～0.4D L _s＝2～10d

D _d=D-D _sL _d=1.5～4D _sIn the following formula, D is the diameter of enhanced tube, and d twines the used diameter wiry of little spring, D _sBe the little spring diameter that twines, L _sBe little spring pitch, D _dBe big spring diameter, L _dBe big spring pitch.

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