CN2207559Y

CN2207559Y - Shaped heat transfer tube

Info

Publication number: CN2207559Y
Application number: CN 94232012
Authority: CN
Inventors: 洪晓波; 洪绰庭
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-12-26
Filing date: 1994-12-26
Publication date: 1995-09-13
Anticipated expiration: 2004-12-26

Abstract

The utility model relates to a shaped heat transfer tube which is characterized in that an isometrical smooth circular heat-transfer tube is processed as a shaped tube with a plenty of expanding and shrinking circular section tube couplings connected with each other end to end. The tube has the advantages of great thermal difference during the heat transfer tube transfers heat, and small thermal resistance of a boundary layer on the surface of the tube inner wall without easy scale formation on the inner wall. Furthermore, the heat transfer tube is used in steam-water heat exchange, coagulating water on the outer wall of tubes can pitch down from each tube coupling, so integral laminated film layers can not be formed, which can lower thermal resistance of the outside of the tubes.

Description

Shaped heat transfer tube

The utility model relates to a kind of shape tube, particularly a kind of special-shaped heat-transfer pipe.

The heat-transfer pipe that on interchanger, uses at present, all adopt isometrical pipe, high cryogen (liquid, gas, steam) flows in pipe or outside the pipe, high temperature fluid with heat pass to cryogen by tube wall, reach heating cryogen or cooling down high-temperature fluid, satisfy the needs of various processes or life.In this heat exchanger, when fluid flowed in pipe, internal face can form " boundary layer ", this " boundary layer " is laminar condition, and flow velocity is low, makes that the temperature on each cross section of pipe is inconsistent, there is the bigger temperature difference, thereby reduced the inside and outside heat transfer temperature difference of pipe.In addition,, be detained the fouling nucleus easily, quickened foulant and on inwall, deposited, generate incrustation scale because the flow velocity in " boundary layer " is low.Because the thermal conductivity factor of " boundary layer " and incrustation scale is low, thermal resistance is big, therefore greatly reduces the heat transfer coefficient of heat-transfer pipe.Tube wall incrustation also can produce underdeposit corrosion and increase flow resistance in addition, and waste water pump electric power shortens equipment life.With a kind of fluid, " boundary layer " is thick, and thermal resistance is big, and heat transfer coefficient is low.The utility model has designed a kind of special-shaped heat-transfer pipe for overcoming the problems referred to above, and it is big that he itself has a heat transfer temperature difference, little, the less scaling characteristics of " boundary layer " thermal resistance.

The purpose of this utility model provides a kind of by changing the flow regime in the heat-transfer pipe, and the approach that promptly produces whirlpool and attenuate " boundary layer " thickness in the flow process improves the special-shaped heat-transfer pipe of heat transfer coefficient.

The utility model is to adopt this method to realize: an isometrical smooth circular heat-transfer pipe is processed into shape tube, promptly has a plurality of end to end expansions thereon and shrink shape circle cross section tube coupling.Replace isometrical smooth circular heat-transfer pipe with this special-shaped heat-transfer pipe, fluid is TRANSFER BY PULSATING FLOW in this special-shaped heat-transfer pipe, at the expansion segment of each tube coupling, produces whirlpool, stirred fluid; At contraction section, produce and quicken, wash away " boundary layer " on the tube wall, thereby the effect of playing the continuous stirring fluid and washing away " boundary layer ", make the temperature on each cross section of heat-transfer pipe be tending towards equal, increase the inside and outside heat transfer temperature difference of pipe, and make " boundary layer " reduced thickness, prevent fouling, reduce the purpose of thermal resistance.

The utility model compared with prior art, it is big to have the heat-transfer pipe heat transfer temperature difference, inside pipe wall face " boundary layer " thermal resistance is little, the characteristics that inwall is less scaling, and heat-transfer pipe is used for vapour-hydrothermal exchange, and the condensate water on the pipe outer wall can fall down the rete that unlikely formation is complete in flakes from each tube coupling, can reduce the pipe external thermal resistance, have the short tube heat-transfer character.Because the acting in conjunction of These characteristics makes heat transfer coefficient improve greatly, can reach more than 3 times, under identical heat output, required heat transfer area significantly reduces.Be difficult for scaling in the heat-transfer pipe in addition, the no strong throttling of flowing, the inefficient flow drag losses is little, saves power consumption, and prevents underdeposit corrosion.Another characteristics are that shape tube heat transfer axial elasticity is good, can be used as housing and tube bundle heat expansion compensation, make heat exchanger can adopt fixed tube sheet, simplified structure, convenient for maintaining.

Concrete structure of the present utility model and embodiment are provided by the following drawings.

Fig. 1 is the general structure schematic diagram of the special-shaped heat-transfer pipe of the utility model.

Fig. 2 is the local B enlarged diagram of Fig. 1 heat-transfer pipe.

Below in conjunction with accompanying drawing concrete structure of the present utility model and embodiment are done with further instruction.

See shown in Fig. 1-2: the both ends caliber size of special-shaped heat-transfer pipe is unequal, and a big end is fluid inlet end D ₀, its external diameter equals tube coupling t section maximum outside diameter, and a little end external diameter equals tube coupling t section minimum outer diameter D.Tube coupling t length is got 2-3 times of tube coupling minimum outer diameter D; The last maximum outside diameter of tube coupling t is 1.3-1.4 with the ratio of minimum outer diameter; Expansion segment and contraction section have the garden arc transition of two radius r; R=1/2 (D ₀-D); The arrival end of tube coupling t has isometrical pipe, the about 2r of length.Special-shaped heat-transfer pipe entrance end respectively have one section isometrical pipe l or

Claims

1, a kind of special-shaped heat-transfer pipe is characterized in that: have a plurality of end to end expansions thereon and shrink shape circle cross section tube coupling.

2, by the described heat-transfer pipe of claim 1, it is characterized in that: the both ends caliber size of special-shaped heat-transfer pipe is unequal, and a big end is fluid inlet end D ₀, its external diameter equals tube coupling t section maximum outside diameter, and a little end outer diameter D equals tube coupling t section minimum outer diameter, and tube coupling t length is 2-3 times of tube coupling minimum outer diameter D; Tube coupling t goes up maximum outside diameter D ₀With the ratio of minimum outer diameter D be 1.3-1.4; Expansion segment and contraction section have the garden arc transition of two radius r; R=1/2 (D-D); The arrival end of tube coupling t has isometrical pipe, and length is 2-3r, and special-shaped heat-transfer pipe entrance end respectively has one section isometrical pipe l or l+D.