CN102445104A

CN102445104A - Method for improving heat transfer coefficient of heat exchanger by utilizing medium shear force

Info

Publication number: CN102445104A
Application number: CN2011104050345A
Authority: CN
Inventors: 姚光纯; 徐德懿
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-12-08
Filing date: 2011-12-08
Publication date: 2012-05-09

Abstract

The invention discloses a method for improving the heat transfer coefficient of a heat exchanger by utilizing medium shear force, which is characterized in that: a pulsating generator capable of allowing fluids in the whole runner of the heat exchanger to generate pulsating flow is arranged in front of an inlet of the heat exchanger; by adjusting the pulse generator, the pulsating frequencies of two fluids change, and pulsating waveforms of the fluids at the two sides of a heat exchange surface (1) are mutually staggered until peaks (4) and peaks, and troughs (5) and troughs respectively and homogeneously correspond to each other at one point on the heat exchange surface, so that the fluids pulsate to generate shear force; and the heat exchange surface vibrates under the action of the shear force, the vibration of the heat exchange surface damages a fluid stagnant layer and strips a dirt layer, and the heat resistance value of the fluids is reduced, thereby the heat transfer coefficient of a dividing wall type heat exchanger is improved. According to the method for improving the heat transfer coefficient of the heat exchanger, the heat exchange surface can vibrate under the action of the shear force without changing the structure of the heat exchanger by only needing to adjust the pulsating generator appropriately, therefore, the heat transfer coefficient of the heat exchanger is improved, the structure is simple, the applicability is strong, and the operation and maintenance are convenient.

Description

Utilize the medium shearing force to improve the method for heat exchanger heat transfer coefficient

Technical field

The present invention relates to a kind of method of utilizing medium (fluid) shearing force to improve the heat exchanger heat transfer coefficient.

Background technology

Heat exchanger is a kind of energy-saving equipment of realizing that heat transmits between the material, and is general in sector applications such as oil, chemical industry, metallurgy, electric power, light industry, food.Heat exchanger accounts for about 40% of total number of devices in the various devices of oil refining, chemical industry, accounts for the 30%-45% of gross investment.Along with the development of power-saving technology, the application of heat exchanger constantly enlarges in recent years, has brought remarkable economic efficiency thus.At present; Heat exchanger more than 90% is a dividing wall type heat exchanger; It is basic from the essence of conducting heat, improving heat transfer coefficient, so for a long time, people hope that dividing wall type heat exchanger can reach than higher heat transfer coefficient; Thereby obtain a kind of ideal type heat exchanger, for energy savings and environmental protection are made contributions.Up to now, how to improve the heat transfer coefficient of heat exchanger, having of studying from change fluid state aspect is a lot; But great majority all are the flow regimes of improving the heat exchanger inner fluid from this body structure that changes dividing wall type heat exchanger; Like acanthopore diaphragm pipe, spiral flat tube, the varying cross-section duct mentioned in the shell-and-tube heat exchanger progress, CN101566437A processes the composite sleeve double-helix structure with tubulation, and the agitator that adds a spiral among the CN101226041A; Thermograde circulation way when having broken laminar flow; But their structure is more complicated all, also has from the CN2802425Y of the fluid-flow mode that changes shell side, or changes the form of shell side deflection plate.These all more or less raising the heat transfer efficiency of heat exchanger, but all have various problems, high such as material is required, clean difficulty, complex structure.

Summary of the invention

To improving the existing problem of heat exchanger heat transfer coefficient in the above-mentioned prior art; The present invention is from influencing the fluid thermal resistance; Cause lower principal element fluid detention layer of heat exchanger heat transfer system and dirt layer to be set about; Propose to utilize the medium shearing force to make heat-transfer surface produce vibration and destroyed the fluid detention layer, peel off the dirt layer, reduced the fluid thermal resistance, improved the method for heat exchanger heat transfer coefficient.

The technical scheme that the technical problem that the present invention will solve is taked is: before the inlet of heat exchanger, be provided with the flutter generator that can make the whole runner inner fluid of heat exchanger medium produce TRANSFER BY PULSATING FLOW; Through regulating flutter generator; The frequency of two fluid pulsations is changed, and it is a bit all corresponding on heat-transfer surface respectively with crest, trough and trough to its crest that the waveform of heat-transfer surface both sides fluid pulsation is staggered each other, makes fluid pulsation and produce shearing force; Heat-transfer surface receives the shearing force effect and vibrates; Heat-transfer surface flutter failure fluid detention layer with peel off dirt layer, reduce the fluid thermal resistance, thereby improve the heat exchanger heat transfer coefficient.

The present invention is through regulating flutter generator; The frequency of heat-transfer surface both sides fluid pulsation is changed; It is a bit all corresponding on heat-transfer surface respectively with crest, trough and trough to crest that the waveform of heat-transfer surface both sides fluid pulsation is staggered each other, makes fluid pulsation and produce shearing force, and heat-transfer surface receives the fluid pulsation shearing force and vibrates; Because the heat-transfer surface vibration destroys with the dirt layer fluid detention layer and peels off; Reduce the fluid thermal resistance, thereby can improve the heat exchanger heat transfer condition significantly, improve the heat exchanger heat transfer coefficient.The method that the present invention improves the heat exchanger heat transfer coefficient need not change this body structure of heat exchanger; Only need suitably to regulate flutter generator; Just can make heat-transfer surface receive the shearing force effect that fluid media (medium) produces and vibrate, the present invention not only can improve the heat exchanger heat transfer coefficient, and simple in structure; Applicability is strong, convenient operating maintenance.

Description of drawings

Fig. 1 is the fluid pulsation oscillogram through heat exchanger both sides behind the flutter generator,

Fig. 2 is a heat exchanger both sides fluid pulsation oscillogram behind the adjusting flutter generator,

Fig. 3 is the heat exchanger both sides fluid pulsation oscillogram of regulating when crest and trough just in time all stagger behind the flutter generator,

Fig. 4 is the force diagram that heat-transfer surface receives the shearing force effect.

Heat-transfer surface 2, A point vertical plane 3, B point vertical plane 4, crest 5, trough in the drawings, 1.

The specific embodiment

In Fig. 1, Fig. 2, Fig. 3 and Fig. 4; Be provided with flutter generator before heat exchanger (dividing wall type) inlet, as shown in Figure 1, flutter generator makes fluid (medium) generation of heat-transfer surface 1 both sides in the whole runner of heat exchanger pulse in the opposite direction but crest 4 and the corresponding TRANSFER BY PULSATING FLOW of trough 5 same point on heat-transfer surface; The fluid media (medium) of heat-transfer surface upside is pulsed to the right; The fluid media (medium) of heat-transfer surface downside is pulsed left, and the trough 5 of heat-transfer surface upside fluid pulsation is corresponding on the point of the A on heat-transfer surface vertical plane 2 with the crest 4 of downside fluid pulsation, and the crest 4 of heat-transfer surface upside fluid pulsation is corresponding on the point of the B on heat-transfer surface vertical plane 3 with the trough 5 of downside fluid pulsation; In two fluid pulsation processes; Because amplitude is identical, it is zero that the shearing force that receive on heat-transfer surface any point this moment is made a concerted effort, and it is planar that heat-transfer surface is level.As shown in Figure 2; Regulate flutter generator, the frequency of two fluid pulsations is changed, make the waveform of the fluid pulsation of the heat-transfer surface both sides angle that staggers each other; The crest 4 of the trough 5 of side liquid and following side liquid is not corresponding on the point of the A on heat-transfer surface vertical plane 2 on the heat-transfer surface; The crest 4 of heat-transfer surface upside fluid pulsation and the trough 5 of downside fluid pulsation are not corresponding on the point of the B on heat-transfer surface vertical plane 3, and produced shearing force at two fluids this moment in the pulsation process, and the shearing force that receives on heat-transfer surface any point is non-vanishing with joint efforts; Each point can receive the shearing force effect on the heat-transfer surface, thereby makes heat-transfer surface produce vibration.As shown in Figure 3; When regulating flutter generator; When making the waveform of the fluid pulsation of heat-transfer surface both sides just in time become 90 degree phase angles to stagger each other; The trough 5 of heat-transfer surface upside fluid pulsation is just in time corresponding on the point of the A on heat-transfer surface vertical plane 2 with the trough 5 of downside fluid pulsation; The crest 4 of heat-transfer surface upside fluid pulsation is just in time corresponding on the point of the B on heat-transfer surface vertical plane 3 with the crest 4 of downside fluid pulsation, and promptly just in time same point is corresponding on heat-transfer surface for the crest (trough) of the ripple honeybee (trough) of heat-transfer surface upside and downside.As shown in Figure 4, it is maximum that this moment, crest belonged to the shearing force that receives on the heat-transfer surface of corresponding points, and the heat-transfer surface vibration frequency is maximum, because the heat-transfer surface vibration has destroyed the fluid detention layer and peeled off the dirt layer, reduced the fluid thermal resistance, thereby can improve the heat exchanger heat transfer coefficient.

Claims

1. utilize the medium shearing force to improve the method for heat exchanger heat transfer coefficient; It is characterized in that: before the inlet of heat exchanger, be provided with the flutter generator that can make the whole runner inner fluid of heat exchanger medium produce TRANSFER BY PULSATING FLOW; Through regulating flutter generator; The frequency of two fluid pulsations is changed, and it is a bit all corresponding on heat-transfer surface respectively with crest, trough (5) and trough to its crest (4) that the waveform of heat-transfer surface (1) both sides fluid pulsation is staggered each other, makes fluid pulsation and produce shearing force; Heat-transfer surface receives the shearing force effect and vibrates; Heat-transfer surface flutter failure fluid detention layer with peel off dirt layer, reduce the fluid thermal resistance, thereby improve the heat exchanger heat transfer coefficient.