CN102564168A - Longitudinal flow shell-and-tube heat exchanger - Google Patents

Abstract

The invention discloses a longitudinal flow shell-and-tube heat exchanger, which belongs to shell-and-tube heat exchangers and solves the problem that the fluid dissipative work is increased during heat transfer enhancement of the conventional shell-and-tube heat exchanger. The longitudinal flow shell-and-tube heat exchanger comprises a shell, left and right tube plates and left and right seal heads, wherein the side wall of the shell is provided with a shell pass inlet and a shell pass outlet; the left and right tube plates are arranged in the shell respectively; a plurality of heat transfer tubes are fixed through the left and right tube plates; two ends of the shell are sealed by the left and right seal heads; the left and right seal heads are provided with a tube pass inlet and a tube pass outlet respectively; the heat transfer tubes are spiral heat transfer tubes; and in a direction vertical to a shell pass fluid flowing direction, the heat transfer tubes which contact the inner wall of the shell are supported through contact points of adjacent heat transfer tubes and contact points on the inner wall of the shell, and the other heat transfer tubes support and fix one another through the contact points of the adjacent heat transfer tubes. The longitudinal flow shell-and-tube heat exchanger is compact in structure, small in volume and large in heat exchange area, and saves the investment cost; and the contact points among tube bundles of the heat transfer tubes increase the turbulence intensity of the fluid during shell pass flow, the fluid is uniformly mixed, and the shell pass pressure drop is greatly reduced, so that the comprehensive heat exchange performance of the longitudinal flow shell-and-tube heat exchanger is improved.

Description

A kind of shell-and-tube heat exchanger that vertically flows

Technical field

The invention belongs to shell-and-tube heat exchanger, be specifically related to a kind of shell-and-tube heat exchanger that vertically flows.

Background technology

Shell-and-tube heat exchanger is used widely in industries such as oil, chemical industry, metallurgy, electric power with its advantage such as simple in structure, cheap, accounts for 70% of heat exchanger total amount.The shell-side baffling structure of shell-and-tube heat exchanger plays whole flow-disturbing effect on the one hand, supports and fixation having restrained on the other hand.By the flow direction of shell-side fluid, shell-and-tube heat exchanger can be divided into three types: 1. lateral flow like traditional segmental baffle, makes shell-side fluid vertically wash away the formation lateral flow to heat-transfer pipe; 2. vertically flow,, make shell-side fluid be parallel to heat-transfer pipe and vertically flow like the deflection bar type heat exchanger; 3. helical flow like helical baffles, totally flows shell-side fluid in the shape of a spiral.Different shell side nowed formings, the performance of shell-and-tube heat exchanger appears than big-difference.Discovered in recent years that mobile being become by lateral flow of shell-side fluid has following plurality of advantages when vertically flowing: flow resistance reduced, and flow pressure drop reduces, and heat transfer area is fully used, and the complex heat transfer performance of shell side obviously improves; Resistance to shock and resistive connection dirt performance significantly improve, and prolonged the service life of equipment, and maintenance cost reduces; Supporter simply makes manufacturing more convenient, and has practiced thrift the material and facility investment; See the Wu Jin magnitude, " Study on Structures of Longitudinal Flow Heat Exchangers progress " literary composition, (" chemical industry progress ", 21:306-310,2002).Therefore it is significant for improving heat exchanger performance and energy savings to study new vertical flow tube shell type heat exchanger.

Heat conduction reinforced for longitudinal-flow heat exchanger generally considered from tube side and two aspects of shell side.Heat conduction reinforced efficient heat conducting tube reinforcement techniques such as band (groove) pipe, spiral grooved tube, convergent-divergent pipe, screwed pipe, self-supporting pipe, the heat conduction reinforced reinforcement techniques such as full circle shape deflection plate, rod baffle, cavity ring, pipe self-supporting that mainly contain of shell side of mainly containing of tube side; See (1) R.Mukherjee, Use double-segmental baffles in the shell-and-tube heat exchangers, Chem.Eng.Progress, 88:47-52,1992; (2) R.Mukherjee, Don ' t let baffling baffle you, Chemical Engineering Progress, 92:72-79,1996; (3) H.Li and V.Kottke; Effect of baffle spacing on pressure drop and local heat transfer in shell-and-tube heat exchangers for staggered tube arrangement; Int.J.Heat Mass Transfer; 41:1303-1311,1998; (4) H.Li; V. Kottkeb; Analysis of local shell side heat and mass transfer in the shell-and-tube heat exchanger with disc-and-doughnut; Int.J.of Heat and Mass Transfer, 42:3509-3521,1999; (5) G.N.Xie et al.; Heat transfer analysis for shell-and-tube heat exchangers with experimental data by artificial neural networks approach; Applied Thermal Engineering; 27:1096-1104,2007; (6) A.L.H.Costa, E.M.Queiroz, Design optimization of shell-and-tube heat exchangers, Applied Thermal Engineering, 2008 (on line); (7) Q.W.Dong, Y.Q.Wang, M.S.Liu; Numerical and experimental investigation of shell side characteristics for ROD baffle heat exchanger; Applied Thermal Engineering, 28:651-660,2008.Though the efficient enhanced tubes of great majority all have certain effect to the heat exchange reinforcement of tube side and shell side, mainly still are used to strengthen tube side, not very big to the effect of shell side.Have certain advantage though the heat conduction reinforced technology of above-mentioned shell side is compared the cambered plate heat exchanger, all exist certain weak point, for example shortcoming such as processing or difficult installation, fluid resistance is excessive, investment cost is higher, narrow application range.From in general, still to low flow resistance, firm, simple in structure, easily manufactured and economize aspect such as material and constantly develop, trend is to remove deflection plate to shell side augmentation of heat transfer technology, comes to support mutually with the some contact between the opposite sex pipe, and forms the shell side runner.So both economized material, and can take all factors into consideration the correlation of tube construction and shell side structure again, to reach the synchronous reinforced that tube side and shell side conduct heat; See Jiang Nan etc., " shell-and-tube heat exchanger shell side augmentation of heat transfer progress " literary composition, (" chemical fertilizer industry ", 25 (6): 27-32,1998).

Summary of the invention

The present invention provides a kind of shell-and-tube heat exchanger that vertically flows, the problem that the dissipation work of shearing force, frictional force and the fluid on existing heat conduction reinforced while fluid of shell-and-tube heat exchanger of solution and tube bank surface increases greatly.

A kind of shell-and-tube heat exchanger that vertically flows of the present invention comprises housing, left tube sheet, right tube sheet, left end socket and right end socket, and housing sidewall has shell side import and shell side outlet; Be respectively equipped with left tube sheet and right tube sheet in the housing; Many heat-transfer pipes are fixed through left and right tube sheet and by left and right tube sheet, and the housing two ends by left end socket and the sealing of right end socket, have the outlet of tube side import and tube side respectively respectively on the left and right end socket; Tube side import and export and the reverse setting of shell side import and export is characterized in that:

Said heat-transfer pipe is the helical form heat-transfer pipe; On perpendicular to the shell-side fluid flow direction; The contact point of helical form heat-transfer pipe through adjacent helical form heat-transfer pipe of contact inner walls and the support of inner walls contact point, other helical form heat-transfer pipes all contact point through adjacent helical form heat-transfer pipe support each other and fix;

Said helical form heat-transfer pipe, its arbitrary shape of cross section is the circle of equal radii, and helical form heat-transfer pipe inside diameter D is 1.4～140mm, and wall thickness d is 0.2～20mm; Helical form heat-transfer pipe central axis is cylindrical helix, in cartesian coordinate system, satisfies following condition:

x＝a×cosθ，

y＝a×sinθ，

z＝S×θ/2π，

Wherein, x, y, z are respectively the coordinate of each point x, y, z axle central axis in cartesian coordinate system on the cylindrical helix, and z is 100～20000mm, and variable θ is an angle, and radius of spin a is 0.25～25mm, and pitch S is 4～400mm.

Described a kind of shell-and-tube heat exchanger that vertically flows is characterized in that:

Said thickness of shell is 1～100mm.

Heat-transfer pipe of the present invention adopts the helical form heat-transfer pipe, relies on the interbank contact point of heat-transfer pipe to come support tube, has omitted shell-side deflection plate, rod baffle supporting member; Make heat exchanger structure compact; The general heat exchanger of volume ratio is little, and heat exchange area is bigger than general heat exchanger, has saved investment cost; Changed the interbank flow-disturbing mode of heat-transfer pipe, the interbank contact point of heat-transfer pipe is as the turbulent element of shell side, and shell-side fluid totally along the heat-transfer pipe axial flow, promptly vertically flows under the effect of heat-transfer pipe helicoid, simultaneously with horizontal screw.The periodically-varied of this flow velocity and the flow direction has been strengthened the axial mixing and the less turbulence of fluid.Simultaneously, fluid is flowed through and is formed the wake flow that breaks away from tube wall behind the contact point of adjacent pipe, has increased the turbulivity of fluid self, has destroyed the heat transfer boundary layer of fluid on tube wall, thereby has realized augmentation of heat transfer.Theoretical according to the core flow augmentation of heat transfer; Because there are not unnecessary flow-disturbing and support component, so thereby its front face area has reduced viscous dissipation greatly, in addition; Because shell-side fluid totally is vertically to flow; Its resistance mainly is to plunder heat-transfer pipe outward and the viscous force that produces by fluid, so power consumption is little, and comprehensive heat exchange property is high.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is for removing the housing parts schematic perspective view of left and right sides tube sheet and left and right sides end socket;

Fig. 3 is the schematic perspective view of helical form heat-transfer pipe;

Fig. 4 is the sketch map of helical form heat-transfer pipe central shaft;

Fig. 5 is the change curve of heat Q under the embodiment one different Reynolds number Re;

Fig. 6 is the change curve of pressure drop Δ P under the embodiment one different Reynolds number Re;

Fig. 7 is the change curve of overall characteristic ratio h/ Δ P under the embodiment one different Reynolds number Re;

Fig. 8 is the change curve of efficiency evaluation coefficient EEC under the embodiment one different Reynolds number Re;

Fig. 9 is the change curve of heat Q under the embodiment one different power consumption U Δ P number;

Figure 10 is the change curve of efficiency evaluation coefficient EEC under the embodiment one different power consumption U Δ P number.

The specific embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is further specified.

As shown in Figure 1, embodiments of the invention one comprise housing 9, left tube sheet 2, right tube sheet 10, left end socket 1 and right end socket 7; Housing sidewall has shell side import 3 and shell side outlet 6; Be respectively equipped with left tube sheet 2 in the housing 9 and fix through left and right tube sheet and by left and right tube sheet with 10,21 heat-transfer pipes 5 of right tube sheet, the housing two ends are respectively by left end socket 1 and right end socket 7 sealings; Have tube side import 11 and tube side outlet 8, tube side import and export and the reverse setting of shell side import and export on the left and right end socket respectively.

As shown in Figure 2, the housing parts of embodiment one removal left and right sides tube sheet and left and right sides end socket only represents shell side import 3, shell side outlet 6, heat-transfer pipe 5 and housing 9 among the figure; The housing internal diameter is 144mm, housing wall thickness 12mm; Heat-transfer pipe 5 is the helical form heat-transfer pipe; On perpendicular to the shell-side fluid flow direction; The contact point 4 of the helical form heat-transfer pipe of contact inner walls through adjacent helical form heat-transfer pipe supports with the inner walls contact point, all supports and fixing each other of the contact point 4 through adjacent helical form heat-transfer pipe of other helical form heat-transfer pipes.

As shown in Figure 3, the arbitrary shape of cross section of helical form heat-transfer pipe is the circle of equal radii, and helical form heat-transfer pipe inside diameter D is 16mm, and wall thickness d is 1mm;

As shown in Figure 4, helical form heat-transfer pipe central axis is cylindrical helix, in cartesian coordinate system, satisfies following condition:

x＝a×cosθ，

y＝a×sinθ，

z＝S×θ/2π，

Z is 1000mm, and radius of spin a is 2.5mm, and pitch S is 40mm.

Embodiment two, and version is identical with embodiment one, and 12 heat-transfer pipes are fixed through left and right tube sheet and by left and right tube sheet, and the housing internal diameter is 9.5mm, housing wall thickness 1mm;

The arbitrary shape of cross section of helical form heat-transfer pipe is the circle of equal radii, and helical form heat-transfer pipe inside diameter D is 1.4mm, and wall thickness d is 0.2mm; Helical form heat-transfer pipe central axis is cylindrical helix, in cartesian coordinate system, satisfies following condition:

x＝a×cosθ，

y＝a×sinθ，

z＝S×θ/2π，

Wherein, x, y, z are respectively the coordinate of each point x, y, z axle central axis in cartesian coordinate system on the cylindrical helix, and z is 100mm, and variable θ is an angle, and radius of spin a is 0.25mm, and pitch S is 4mm.

Embodiment three, and version is identical with embodiment one, and 480 heat-transfer pipes are fixed through left and right tube sheet and by left and right tube sheet, and the housing internal diameter is 4180mm, housing wall thickness 100mm;

The arbitrary shape of cross section of helical form heat-transfer pipe is the circle of equal radii, and helical form heat-transfer pipe inside diameter D is 140mm, and wall thickness d is 20mm; Helical form heat-transfer pipe central axis is cylindrical helix, in cartesian coordinate system, satisfies following condition:

x＝a×cosθ，

y＝a×sinθ，

z＝S×θ/2π，

Wherein, x, y, z are respectively the coordinate of each point x, y, z axle central axis in cartesian coordinate system on the cylindrical helix, and z is 20000mm, and variable θ is an angle, and radius of spin a is 25mm, and pitch S is 400mm.

Fig. 5～Figure 10 carries out The results of numerical simulation for the whole heat exchanger to embodiment one; Fluid in the numerical simulation adopts water; The reynolds number Re scope is 6000～18000, the data of black side's point expression deflection rod heat exchanger among the figure, and the black round dot is represented the data of embodiment one.Boundary condition is: given even inlet velocity and inlet temperature 300K; Tube wall temperature is 330K, and the shell wall side surface is adiabatic.

Reynolds number Re defines as follows:

Re＝u×d/υ，

U is a fluid velocity in the formula, and d is the heat-transfer pipe internal diameter, and υ is the fluid motion viscosity.

Heat convection amount Q between heat-transfer pipe wall and fluid defines as follows:

$Q=\frac{c_p\mathrm{\ρu\π}{d}^2(T_{\mathrm{out}}-T_{\mathrm{in}})}{4},$

C in the formula _pBe the fluid ratio thermal capacitance, ρ is a fluid density, and u is a fluid velocity, T _OutBe fluid outlet temperature, T _InBe the fluid intake temperature.

Convection transfer rate h defines as follows:

$h=\frac{Q}{\mathrm{\πdL}(T_w-T_f)},$

L is a heat-transfer pipe length in the formula, T _wBe heat-transfer pipe outside wall temperature, T _fBe the fluid mean temperature.

Efficiency evaluation coefficient EEC defines as follows:

$\mathrm{EEC}=\frac{Q/{\mathrm{<figure-callout\; id="0"\; label="Q"\; filenames="HDA0000131346160000032.png,HDA0000131346160000041.png"\; state="\{\{state\}\}">Q</figure-callout>}}_0}{\mathrm{\&Delta;P}/\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="HDA0000131346160000032.png,HDA0000131346160000041.png"\; state="\{\{state\}\}">P</figure-callout>}}_0},$

Q is the heat of embodiment one in the formula, Q ₀Be the heat of deflection rod heat exchanger, Δ P is the import and export pressure drop of embodiment one, Δ P ₀Import and export pressure drop for deflection rod heat exchanger.

Fig. 5 and Fig. 6 are respectively under different Reynolds number Re, fluid flow through embodiment one and the heat Q of deflection rod heat exchanger and the variation of pressure drop Δ P.As can be seen from the figure, the heat Q of two kinds of structure heat exchanger shell pass is identical with pressure drop Δ P variation tendency, all increases along with the increase of reynolds number Re.The heat of embodiment one is less than rod baffle, and the heat of embodiment one was 67.9% of a deflection rod heat exchanger heat when both differed maximum.But the pressure drop of embodiment one is all the time much smaller than rod baffle, and along with the increase of reynolds number Re, the pressure drop difference of the two is increasing, and the pressure drop of embodiment one was 13.8% of deflection rod heat exchanger pressure drop when both differed maximum.

Fig. 7 is under different Reynolds number Re, the variation of embodiment one and the deflection rod heat exchanger coefficient of heat transfer and pressure drop ratio h/ Δ P.As can be seen from the figure, under identical reynolds number Re, the ratio h/ Δ P of embodiment one is all the time greater than deflection rod heat exchanger far away, and the ratio of embodiment one was 3.8 times of deflection rod heat exchanger when both differed maximum.

The efficiency evaluation coefficient EEC value that Fig. 8 obtains for embodiment one and deflection rod heat exchanger compare is with the Changing Pattern of reynolds number Re; As can be seen from the figure; Between reynolds number Re=6000～18000, the heat exchanger comprehensive effectiveness EEC value of embodiment one is all greater than 4, this explanation; Embodiment one compares with deflection rod heat exchanger, and combination property has improved 4 times under identical reynolds number Re.

Fig. 9 is under different power consumption U Δ P, and the flow through heat Q of embodiment one and deflection rod heat exchanger of fluid changes.The heat of two kinds of structure heat exchanger shell pass all increases along with the increase of power consumption U Δ P.The heat beginning of embodiment one, wherein, U was the shell side flow velocity all the time greater than deflection rod heat exchanger.

The efficiency evaluation coefficient EEC value that Figure 10 obtains for embodiment one and deflection rod heat exchanger compare is with the change curve of power consumption U Δ P; As can be seen from the figure; Between reynolds number Re=6000～18000, the heat exchanger combination property EEC value of embodiment one is between 1.12～1.24, and this illustrative embodiment one is compared with deflection rod heat exchanger under same power consumption; Heat exchange property is the highest can to improve 24%, and energy-saving effect is remarkable.

Claims (2)

1. the shell-and-tube heat exchanger that vertically flows comprises housing, left tube sheet, right tube sheet, left end socket and right end socket, and housing sidewall has shell side import and shell side outlet; Be respectively equipped with left tube sheet and right tube sheet in the housing; Many heat-transfer pipes are fixed through left and right tube sheet and by left and right tube sheet, and the housing two ends by left end socket and the sealing of right end socket, have the outlet of tube side import and tube side respectively respectively on the left and right end socket; Tube side import and export and the reverse setting of shell side import and export is characterized in that:

Said heat-transfer pipe is the helical form heat-transfer pipe; On perpendicular to the shell-side fluid flow direction; The contact point of helical form heat-transfer pipe through adjacent helical form heat-transfer pipe of contact inner walls and the support of inner walls contact point, other helical form heat-transfer pipes all contact point through adjacent helical form heat-transfer pipe support each other and fix;

Said helical form heat-transfer pipe, its arbitrary shape of cross section is the circle of equal radii, and helical form heat-transfer pipe inside diameter D is 1.4～140mm, and wall thickness d is 0.2～20mm; Helical form heat-transfer pipe central axis is cylindrical helix, in cartesian coordinate system, satisfies following condition:

x＝a×cosθ，

y＝a×sinθ，

z＝S×θ/2π，

Wherein, x, y, z are respectively the coordinate of each point x, y, z axle central axis in cartesian coordinate system on the cylindrical helix, and z is 100～20000mm, and variable θ is an angle, and radius of spin a is 0.25～25mm, and pitch S is 4～400mm.

2. a kind of shell-and-tube heat exchanger that vertically flows as claimed in claim 1 is characterized in that:

Said thickness of shell is 1～100mm.

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