Here is a quick cure for finned tube corrosion and heat dissipation

Murphy finned tubes

The problem of tube oxygen corrosion in finned tube heat exchangers has always been a key problem to be solved in the industry. If we can solve the problem of  corrosion in oxygen-containing medium, it will play a positive role in the development of the existing technology. In the long-term production practice, Murphy also summarized some methods to solve the problem of internal corrosion of the fin tube.

Solution to finned tube corrosion 

When designing the heating system of the finned tube heat exchanger, it is necessary to avoid mutual circulation with oxygen as much as possible and to seal as much as possible. When replenishing water to the fin tube, it should be deoxidized. When the  heat exchanger stops heating, it should be fully maintained with a drying method or deoxygenated water. Also, when testing the pressure of the newly installed heat exchanger, whether it is hydraulic testing or adding solvents, non-toxic rust inhibitors should be used.

During use, if the finned tube heat exchanger is not hot, please check whether the water inlet filter is unblocked, the water inlet pipe is hot, the return pipe is hot, and the exhaust valve always releases warm water. In this case, the water filter should be loosened. If it is clogged, you can use a brush and clean water to clean it to solve the problem.

Besides, check whether the pipeline exhaust system is normal, especially for users who have just installed or just completed the modification, check whether the high point of the pipeline and the exhaust valve set at the end of the pipeline discharge the gas in the system; check whether the system pressure is sufficient Big? Do many users use finned tube heat exchangers? Finned tubes in groups at the ends are usually not hot enough. If the temperature difference between the front and rear groups is large and it is not blocked by air, it must be checked. Does the system pressure meet the standard?

Murphy stainless steel laser welding fin tube energy industry heat exchange 3
Murphy Spiral Copper Finned Tube for Air Cooler Heat Exchange 4

At the same time, the following factors will also affect the heat dissipation of the finned tube

(1) The diameter of the fin tube: Many times we will find that the increase in the diameter of the fin tube will improve the corresponding heat dissipation. However, this method is also disadvantageous, so Murphy’s technical experts recommend a comprehensive consideration.

(2) The spacing and height of the tube are also the main reasons that directly affect the heat dissipation of the  tube. If the tube spacing is small, the heat dissipation will inevitably increase. Too large or too small spacing will have adverse effects. It is important to choose the right spacing. The finned tube also has a height. Once the height of the tube is increased, the heat dissipation area will increase, and then the heat dissipation capacity will increase. Besides, no increase is allowed and must be considered reasonable.

(3) The thermal contact resistance and the number of heat sinks will affect the heat dissipation of the heat sink tube. The contact thermal resistance has a great influence.

Finned tube future development 

With the continuous innovation of technology, the application of finned tube heat exchangers in many industries has been significantly improved. For example: HVAC, Chemical, Food&Drink manufacturing etc. With the continuous improvement of people’s daily life, it is increasingly necessary to use finned tubes to protect the environment. Murphy Thermal has always believed that with the continuous updating of technology, the corrosion problem in the finned tube will also be effectively solved.

If want to know more details about finned tubes and other heat exchanger products, please visit our  contact us page.

Want to step up your finned tube and heat exchanger application? You need to read this first

Murphy aluminum fin and tube Marine heat exchanger5

Finned tubes are widely used in power, chemical and other industries. Many spiral heat transfer surfaces or threaded tubes can be regarded as finned tubes. It has a significant effect on expanding the heat exchange area and promoting turbulence, and it has a great effect on both single-phase-convection heat transfer and phase-change convective heat transfer.

The structure of the finned tube heat exchanger is basically the same as the general shell and tube heat exchanger. Just use finned tubes instead of light tubes as the heat transfer surface. Finned tube heat exchangers are also often used to heat or cool the gas outside the tube, and steam or water is passed through the tube, such as air coolers, boiler economizers, radiators, etc.

The finned tube has a wide range of materials, including stainless steel, carbon steel, titanium-copper alloy, etc. The corrosion resistance of the industry has greatly increased.
Laser welding spiral fin tube is a new, wear-resistant and efficient heat exchange material in the fin tube welding industry. It is a high-efficiency energy-saving heat exchange element with high heat exchange efficiency, large heat dissipation area, long service life, and adaptability.

The temperature range is wide, the pressure is high, and it conforms to the national energy-saving and environmental protection emission standards. It is widely used in waste heat recovery, petrochemical industry, power station boilers, economizers, passenger cars, industrial and civil building heating, refrigeration systems and other industries.

Murphy Thermal Energy Technology (Suzhou) Co., Ltd. has been committed to the development and research of integral laser welded finned tubes and single-layer double-layer spiral coils. Now it has been used in boilers, chemicals, wall-hung boilers, ships, waste heat power generation, home improvement, etc. Used in various fields. The surface is most used as a heating surface in the boiler industry. It is environmentally friendly and energy-saving. Laser welding finned tube is currently the most technologically advanced product, which has irreplaceable advantages. The advantages of heat exchange waste heat in boilers and chemical industries have been fully utilized.

The laser welding fin tube is a spiral fin tube laser welding machine that integrates laser technology, hardware molds, and numerical control automatic control into one, simple operation, flexible and convenient production. Overcoming a series of problems such as fracture, slow speed, poor forming and wrinkling of finned tubes during the welding process, and now has successfully mastered all the parameters and parameters in the welding of spiral finned tubes, heat exchangers and other finned tubes. Production and coordination of automatic fixtures.

The spiral finned tube laser welding machine is composed of a high-power automatic laser welding machine, automatic CNC control fixture, automatic feeder and other auxiliary equipment.
Let’s talk about the five characteristics of laser welding of spiral fin tubes:

1: The thickness of the base tube can be 0.8-1.5 mm, and the thickness of the fin can be 0.3-1 mm, which greatly saves material costs compared to other processes.
2: High penetration rate, can prevent crevice corrosion, prolong service life and reduce heat transfer resistance.
3: Break through the material limit and use different materials for processing.
4: Easy secondary processing, can be directly coiled and bent.
5: The welding heat-affected zone is small and the metallographic change is small, making it possible to process small-diameter finned tubes.

 

Murphy aluminum fin and tube Marine heat exchanger4
Murphy aluminum fin and tube Marine heat exchanger3

 

In terms of quality control:
1. The CCD monitoring system is used in the production process to monitor the welding area throughout the process.
2, The first article is approved, and the metallographic analysis system is used to obtain the welding status to ensure that the product quality is qualified before continuous production.
3. Choose high-quality, high-standard materials and start from the source to ensure that the product quality is qualified.
4: Break through the material limit and use different materials for processing.
5: Easy secondary processing, can be directly coiled and bent.
6: The welding heat-affected zone is small, and the metallographic change is small, making it possible to process small diameter fin tubes.
7: The thickness of the base tube can be 0.8-1.5 mm, and the thickness of the fin can be 0.3-1 mm, which greatly saves material costs compared to other processes.

Finned tube heat exchanger working principle

The heat exchanger is the key equipment of the thermodynamic system. The fin tube heat exchanger is a heat exchanger structure with high technical content and complex production process. The cold and hot fluid walls are cross-flow heat exchange. The tube carries refrigerant and the outside of the tube is air.

The main body of the tube is phase change heat transfer. The tube is generally arranged in a serpentine shape with multiple tubes, and the fins are divided into single, double or multi-row structures. This kind of heat exchanger is widely used in petrochemical, aviation, vehicles, power machinery, control points, deep and low temperature, atomic energy, aerospace and other industrial fields.

For example, superheaters, economizers, air preheaters, condensers, deaerators, feedwater heaters, cooling towers, etc. in boiler thermal systems; hot blast stoves, air or gas preheaters in metal smelting systems, Waste heat boilers, etc.; evaporators, condensers, regenerators in refrigeration and low-temperature systems; heating and cooling equipment widely used in the petrochemical industry, sugar evaporators and pulp evaporators in the sugar industry and paper industry, These are numerous examples of heat exchanger applications.

Due to the limited reserves of coal, oil, and natural gas resources in the world, the world is facing an energy shortage situation. All countries are committed to the development of new energy, and actively carry out preheating recovery and energy saving work, so the application of heat exchangers and energy development It is closely related to saving.

In this work, the heat exchanger also plays an important role, and its performance directly affects the efficiency of energy utilization. As an effective device for energy utilization and energy conservation, heat exchangers also play an important role in waste heat utilization, nuclear energy utilization, solar energy utilization, and geothermal energy utilization.

For more information about finned tube get in touch with us.

High-frequency welding finned tube

extruded finned tubes Murphy

How does high-frequency welding finned tube work?

The high-frequency welding finned tube use the skin effect and proximity effect of the high-frequency current to heat the outer surface of the steel strip and the steel tube while the steel strip is wound around the steel pipe, until the plastic state or melting, a certain pressure on the wound steel strip Complete welding next.

This high-frequency welding is actually solid-phase welding. Compared with inlaying, brazing (or integral hot-dip galvanizing) and other methods, it is excellent in terms of product quality (high welding rate of fins, up to 95%), productivity, and degree of automation.

High-frequency welding uses solid resistance heat as an energy source. The resistance heat generated by the high-frequency current in the workpiece during welding heats the surface of the welding zone of the workpiece to a molten or near plastic state, and then applies (or does not apply) upsetting force to achieve metal bonding.

Therefore, it is a solid phase resistance welding method. High-frequency welding can be divided into contact high-frequency welding and induction high-frequency welding according to the way that high-frequency current generates heat in the workpiece.

When contacting high-frequency welding, high-frequency current is introduced into the workpiece through mechanical contact with the workpiece. During induction high-frequency welding, the high-frequency current generates an induction current in the workpiece through the coupling effect of the induction coil outside the workpiece.

High-frequency welding is a highly specialized welding method, and special equipment should be equipped according to the product. High productivity, welding speed up to 30m / min. Mainly used for welding longitudinal or spiral seams when making pipes.

The contents of the two major effects of high-frequency current in high-frequency welding are:

Skin effect: When a conductor is fed with alternating current, the current distribution on the conductor cross-section is uneven, the current density gradually increases from the center of the conductor to the surface, and most of the current only flows along the surface of the conductor.

The lower the resistivity of the conductor, the greater the magnetic permeability, and the higher the frequency of the current, the more significant the skin effect.

Proximity effect: When high-frequency currents flow in opposite directions in two conductors or in a reciprocating conductor, the current will concentrate on a special physical phenomenon that flows on the adjacent side of the conductor.

High-frequency welding usually uses a current frequency range of 300 to 450kHz, and sometimes a frequency as low as 10kHz

 

Murphy high frequency finned tube scaled

 

High-frequency welding fin characteristics

  1. Due to the fast welding speed and the strong self-cooling effect of the weldment, not only is the heat-affected zone small, but it is also not easy to oxidize, so the structure and performance of the weld is very good.
  2. Anti-corrosion performance, wear resistance, low contact thermal resistance, high stability, anti-ashing ability.
  3. Large heat exchange area.

High-frequency welding type

There are two types of high-frequency welding: high-frequency resistance welding and high-frequency induction welding.

High-frequency resistance welding: use rollers or contactors as electrodes to introduce high-frequency current into the workpiece, suitable for continuous longitudinal seam butt welding and spiral lap seam welding of tubes, welding of boiler finned tubes and spiral fins of heat exchangers.The outer diameter of the weldable pipe is 1200 mm, the wall thickness is 16 mm, and the thickness of the ventral pole of the I-beam can be welded 9.5 mm. The productivity is very high.

High-frequency induction welding: the induction coil is used to heat the workpiece, which can weld small-diameter tubes with an outer diameter of 9 mm and thin-wall tubes with a wall thickness of 1 mm. Commonly used for longitudinal seam welding of small and medium diameter steel pipes and brass tubes, but also for girth welding, but the power loss is greater than high-frequency resistance welding.

The main parameters that affect the quality of high-frequency welding are the frequency, power, forming an angle of the workpiece, extrusion force, the distance between the electrode (or induction coil), and the extrusion roller, and the welding speed.

The main equipment includes high-frequency power supply, workpiece forming equipment, and extrusion machinery. High-frequency welding has stable quality, high productivity, and low cost. It is suitable for high-efficiency automatic production lines and is an advanced method for producing seamed pipes.

Need more information? Get in touch with us!

What should you know for laser welding finned tube

tubes finnedtubes murphy

Laser welding finned tube manufacturing

Laser welding finned tube is processed by laser welding machine. Laser welding is a welding method that irradiates a high-intensity laser beam onto the metal surface. Through the interaction of the laser and the metal, the metal absorbs the laser light and converts it into heat, melting the metal to form a cooling crystal. 

Laser welding machine is the most advanced laser welding equipment for finned tubes. Because the welding process is fully automatic and mechanical, the scientific and technological content and quality of laser welding finned tubes are superior to traditional cooling tubes.

The laser welding finned tube has a fully automatic welding process, saving manpower costs; secondly, the laser welding fin is firm, strong, and the test with high tensile strength is qualified. Laser welding is more efficient.

Advantages of laser welding finned tube

1. The laser welding finned tube (finned tube) fin machine has a high degree of automation, and the welding of the fin to the tube and the winding of the tube are synchronized

2. 100% welding rate, laser welding finned tube and fins are strong, the welding strength exceeds 600MPa.

3. The precision of laser welding tube finishing machine is up to 0.05mm

4. 0 contact resistance, achieve high efficiency of heat transfer of spiral finned tube by laser welding.

5. Save production costs. The laser welding finned tube (finned tube) has a smaller fin spacing, less than 2.5mm. Compared with the high frequency welded spiral (spiral) finned tube, the heat transfer area is increased by about 50%, which makes the material cost Reduced, volume reduced heat exchanger.

6. The advantages over conventional MAG / HF welding are of decisive importance. The complete connection between the fin and the base tube brings excellent heat transfer, and the thermal performance of the fin tube is increased by 2.5 times. Continuous welding prevents the notch effect, thereby avoiding the formation of v-corrosion and cracks under the condition that the finned tube may swing. 

The heating of base metals during welding is low and the travel speed is up to 20m / min. Minimize the heat affected zone in the base tube. Therefore, it does not include the complete melting of the tube and the related metallurgical transformation of the parent metal.

Specifically:

· Thin and continuous ideal seams

· Small heat affected area

· Slightly discolored welding parts

· The tubes and fins have only slight microstructure changes

· High heat forms seams

· Since the high welding integrity between the tube and the fins is avoided, the crevice corrosion is avoided, thereby improving safety

· Laser welding is carried out in a protective atmosphere, so the weld is free of impurities.

 
Murphy laser welded finned tube

Application

 Power Plants

· Cooling towers or cooling water recooling plants with dry, dry / wet or wet operation

·  Flue gas cooling and heating in flue gas desulfurisation scrubbers (FGD) and nitrogen removing plants (DENOX)

 Chemical Industry

· Heat exchangers of all kinds for cooling and heating of liquids and gases

· Heat exchangers tor nitric acid (HNO3) plants, e.g. for the fertilizer industry

 Heat Recovery Plants

·  Flue gas coolers

 Heating Industry

·  Primary heat exchangers in gas heating boilers

·  Secondary heat exchangers for domestic water heating in condensing boilers

 General Engineering

·  Heat exchangers for gas cooling of industrial furnaces

·  Heat exchangers for tank heating

·  Oil coolers for vacuum plants, ship plants, pumps etc.

·  Heat exchangers for oil preheating

Dimensions

· Tube outside diameter 8.0–50.0 mm

·  Fin outside diameter 17.0 –80.0 mm

·  Fin pitch 5 –13 fin/inch

·  Fin height 5.0 –17 mm

·  Fin thickness 0.4 – 1.0 mm

·  Maximum tube lengths 12.0 m

Murphy manufactures various types of heat exchanger elments like finned tubes, fin tube coils, stainless pipes, 

heat exchangers, customized according to your need.

For more details about laser welding finned tube and other finned tube please contact us.

 

How to choose low finned tube?

Innenberippte Rohre image murphy

Low finned tube description

Low finned tubes are generally formed by machining on the outer surface of the light tube with a certain height, a certain distance, and a certain thickness of ribs. Finned tubes are mostly used for heat exchange elements of condensers and evaporators of air conditioners, and low-finned tubes are often used in condensers.

It consists of a light pipe and fins “attached” to it. The structural parameters are mainly the inner diameter and outer diameter of the finned tube, the wall thickness of the finned tube, the fin pitch, the fin thickness and the fin height.

The low finned tube mainly relies on the outer rib of the tube (the ribging coefficient is 2 ~ 3) to expand the heat transfer area. Compared with the smooth tube, it has a larger surface area under the same metal material consumption. It is the first heat transfer enhancement from a straight view, but it is actually an increase in the heat transfer area and an increase in the heat transfer coefficient. The fins can make the heat transfer surface peel off the flow layer, and the heat transfer surface disturbance increases and improves The heat transfer effect strengthens the heat transfer twice.

The main factors affecting the enhanced heat transfer of the ribbed surface are the fin height, fin thickness, fin spacing, and thermal conductivity of the fin material. In addition, since one side of the heat transfer wall surface is expanded into a fin surface, the convective heat transfer on the smooth side and the heat conduction of the base wall all have a certain effect on the total heat transfer. The fin pitch size of the low-fin tube needs to be determined according to the surface tension of the liquid and the shear force on the liquid film generated by the flow.

Low finned tube application

The actual application proves that the low finned tube also has excellent anti-fouling performance, because the dirt is often formed along the edge of the wave crest, and the tube will expand and contract with the temperature change during operation. This “accordion” type The effect of expansion and contraction will prevent the formation of dirt. On the light pipe, the dirt will form a layer of cylinder on the wall of the pipe, without any natural mechanism to prevent the generation of dirt. 

Due to the lower fins, the cleaning method and difficulty of the low-fin tubes are exactly the same as for light tubes. In addition, the low-fin tube is made of the ordinary smooth tube as the blank and is processed by simple rolling. Its mechanical strength and corrosion resistance are no less than the original smooth tube blank, which can fully guarantee the long-term reliable operation of the heat exchanger.

Low finned tube performance parameters

There are two important parameters for low-fin tubes to describe their performance, namely the fining ratio β and the fin efficiency η. The fining ratio is expressed by “β”, and its definition can be derived from the formula: β = total external surface area of the finned tube / external surface area of the original smooth tube; the larger the value of β, the more the heat transfer area of the finned tube expands. 

The thermal performance is also enhanced. In the heat exchange process of the finned tube, assuming that the temperature of the fluid in the tube is higher than the temperature of the fluid outside the tube, the heat is transferred from the root of the fin through the tube wall along with the height of the fin through the heat conduction, and the fin also communicates with the surrounding fluid Convective heat transfer occurs, and eventually, the fin temperature gradually decreases along with the fin height.

 

Murphy low finned tube
Murphy low finned tubes

 

Manufacturing process of low finned tube

The low-fin tube is produced by the rolling method (three-roll oblique rolling). Its working principle is: the smooth tube is lined with a mandrel, the tube material is driven by the roller blade to make a spiral linear movement, and is rolled by the roller The hole pattern composed of the groove and the core rod is gradually processed with fins on its outer surface. In order to facilitate the formation of fins. 

The rolling parts adopt three stages of biting, rolling, and shaping during the deformation process, so that the processed fins are complete, smooth, and regular. The finned tube produced by this method is based on the base tube and The outer fin is an organic whole, so there is no problem of contact thermal resistance loss and electrical corrosion. It has good heat transfer efficiency and strong resistance to deformation.

Influencing factors of low finned tube performance

The structural parameters are mainly the inner diameter and outer diameter of the finned tube, the wall thickness of the finned tube, the fin pitch, the fin thickness, and the fin height, etc.

It is generally used in applications where the heat supply coefficient inside the tube is more than double the heat supply coefficient outside the tube. The most typical application is an oil heat exchanger. For condensation and boiling outside the tube, due to the effect of surface tension, it also has a good effect on strengthening heat transfer. Its processing has been industrialized and has been verified by many refineries.

(1) As far as the heat transfer effect is concerned, the primary and secondary relationship between the structural parameters of the low-fin tube is wing pitch → wing height → wing thickness, and the fin pitch is within 1 ~ 2 mm. The thermal performance increases with the increase of the wing pitch. When the wing pitch exceeds 2mm, the heat transfer performance decreases with the increase; the heat transfer performance decreases with the increase of the wing thickness and increases with the increase of the wing height.

(2) The pressure drop outside the finned tube is significantly affected by the height of the wing. The pressure drop increases geometrically with the increase of the wing height. The influence of the wing distance on the pressure drop is also obvious. The pressure drop increases with the wing distance. As it becomes larger, the pressure drop is hardly affected by the thickness of the wings.

(3) When the fluid flow rate inside and outside the tube increases, the heat transfer volume and pressure drop of the finned tube also increase. When the fluid flow rate outside the tube increases, the increase in pressure drop is significantly greater than the increase in heat transfer volume. When the flow rate increases, the pressure drop outside the tube remains unchanged, and the pressure drop inside the tube increases less

For more information about low finned tube get in touch with us.

Brass tube basic instruction

Innenberippte Rohre image murphy

Brass is an alloy of copper and zinc. If it is only composed of copper and zinc, it is called ordinary brass. Brass is often used to make valves, water pipes, connecting pipes of air conditioners and radiators.

Brass tubes are generally used to make heating coil tubes for condensers and coolers and tubes for general purposes. Brass 68 and 70 for condensers and 62 for general purpose cold drawn tubes from 3 to 100 cm OD. Its length is 1-6 meters.

Tubes for condensing cooler and other heat exchange equipment shall be subject to water pressure test with pressure up to 50 kg / cm2, and the test time shall not be less than 10 seconds.

Compared with the shell and tube heat exchanger, the brass tube has the following advantages:

1. High heat transfer coefficient, which is due to high velocity, turbulence and complete countercurrent;

2. The weight of equipment required for unit heat transfer is small;

3. The compensation of temperature deformation is good.

 

brass tubes murphy 1

 

What are the characteristics and uses of brass tubes:

Brass tubes has many advantages in one body. It has high strength of general metal, and it is easy to bend, twist, crack and break compared with general metal. It also has certain frost resistance and impact resistance. Therefore, once installed, the copper tubes in the water supply system in the building can be used safely and reliably, even without maintenance.

Brass tubes also have the characteristics of hard texture, corrosion resistance, high-temperature resistance and high-pressure resistance, which can be used in various environments. Compared with this, the disadvantages of many other pipes are obvious. For example, in the past, the galvanized steel pipes used in residential buildings were easy to rust.

If they were used for a short time, the tap water would turn yellow and the water flow would become smaller. The strength of some other materials will decrease rapidly under high temperatures, which will cause unsafe risks when used in hot water pipes. The melting point of copper is as high as 1083 ℃, and the temperature of the hot water system is negligible for copper pipes. Now it is generally used as a copper pipe for electrical appliances, refrigeration, high-pressure, corrosion-resistant, connection, water channel, electric heating, and industrial purposes.

In addition, because Murphy Thermal brass tubes have the characteristics of firmness and corrosion resistance, it has become the first choice of modern contractors in the installation of water pipes, heating, and cooling pipes in all residential commercial houses. At the same time, it has the characteristics of lightweight, good thermal conductivity, and high low-temperature strength.

It is often used to manufacture heat exchange equipment (such as condenser) and also used to assemble low-temperature pipeline in oxygen production equipment. Small diameter copper pipe is often used to transport pressure liquid (such as lubrication system, oil pressure system, etc.) and pressure pipe used as an instrument.

Get in touch with us for more information about brass tubes.

How does finned tube enhance heat transfer?

high fin tube MURPHY

As flat fin heat exchanger is simple and convenient in structure and manufacture, durable in use and good in applicability, so far, the heat exchanger widely used in Refrigeration Engineering (such as evaporator of ammonia cooling fan, surface air cooler, etc.) still widely uses rectangular flat fin as expansion surface. 

Heat transfer characteristics of fins

Rectangular flat fin has the advantages of simple and compact structure, convenient defrosting, easy manufacturing and so on. At the same time, because it only depends on increasing the heat transfer area to enhance the heat transfer, the effect is poor, especially in the heat exchanger with phase change heat transfer of fluid in the tube and forced flow heat transfer of air outside the tube, the heat resistance of the air side is still the main heat resistance in the whole process despite the addition of fins.

Corrugated fins are widely used in air conditioning and refrigeration because they can increase the length of air passage and mix the air flow sufficiently. Corrugated fins can change the direction of air flow, greatly increase the area of air heat transfer and enhance the fluid disturbance. 

Because of the formation and separation of vortices, the continuous development of the heat boundary layer is reduced or damaged, the characteristics are effectively strengthened, and at the same time, a large loss of resistance is brought, but the increase of heat transfer is greater than the increase of resistance. 

Under the wet condition, the resistance of the slotted fins increases more, and the air volume of the system decreases. At this time, the corrugated fin heat exchanger can be considered, and the fin spacing should not be too small.

 

Murphy finned tubes heat exchanger

 

Heat transfer enhancement solutions

In the research of heat transfer enhancement on the surface of stainless steel fin tube by laser welding, Murphy experts put forward various methods of enhancement, mainly including the following: first, to enhance the turbulence intensity on the air side, the purpose of heat transfer enhancement can be achieved by constantly changing the flow direction of the air flow, mainly by stamping the fins into corrugations, resulting in the type of corrugation fins. 

The second is to use the discontinuous fin surface to gradually disconnect the fin surface along the air flow direction, so as to prevent the development of the air laminar boundary layer on the fin surface, make the boundary layer continuously damaged on each surface, and form a new boundary layer on the next punching strip, and constantly use the leading edge effect of the punching strip to achieve the purpose of strengthening heat exchange. 

There are slat fins, louver fins, etc. belonging to this kind of finsCorrugated fins are widely used in air conditioning and refrigeration because they can increase the length of air passage and mix the air flow sufficiently. Corrugated fins can change the direction of air flow, greatly increase the area of air heat transfer and enhance the fluid disturbance. 

Because of the formation and separation of vortices, the continuous development of the heat boundary layer is reduced or damaged, the heat transfer characteristics are effectively strengthened, and at the same time, a large loss of resistance is brought, but the increase of heat transfer is greater than the increase of resistance. Under the wet condition, the resistance of the slotted fins increases more, and the air volume of the system decreases. At this time, the corrugated fin heat exchanger can be considered, and the fin spacing should not be too small.

For more details about heat transfer please contact us. We can provide customized products according to your individual needs.