Effective heat transfer area

The area added by the fin is not as efficient for heat transfer as bare tube surface owing to resistance to conduction through the fin. The effective heat-transfer area is... 

Plates are pressed from stainless steel, titanium, HasteT loy or any material ductile enough to be formed into a pressing. The specious design of the trough pattern strengthens the plates, increases the effective heat transfer area and produces turbulence in the liquid flow between plates. Plates are pressed in materials between 0.5 and... 

Plates are available with effective heat transfer area from 0.03 to 3.5 m and up to 700 can be contained within the frame of the largest plate-type heat exchanger, providing over 2400 m of surface area. Flow ports and associated pipework are sized in proportion to the plate area and control the maximum liquid throughput. 

The fluid in streams C, E and F bypasses the tubes, which reduces the effective heat-transfer area. 

The ethane is much lighter than the methyl chloride, so it accumulates in the condenser and acts essentially like an inert substance that blankets the condenser. The effect of the inert substance can be considered to reduce either (1) the bubblepoint temperature, thus reducing the differential temperature driving force and reducing heat transfer, or (2) the effective heat transfer area. Either effect is a reduction in heat transfer. So if the ethane is not vented off during the batch, the pressure cannot be controlled even with the chilled water valve wide open. 

A) Tubes provide the effective heat transfer area between the fluids, with one fluid flowing inside the tubes and the other fluid flowing across the tubes on the outside. The tubes may be plain or bare, i.e., having a smooth surface, or they may be finned, having from 400 to 1600 fins/m. These fins are radial, like a pipe thread,... 

For example, scaling up from 30 to 100m3 reduces the S/V from 1.5 to 1. The effective heat-transfer area depends on the shape factor H/D, which in turn is determined by the technology of the mixing device. As rule of thumb, a reactor of 100 m3 has an external heat-transfer surface of about 100 m2 [1]. 

The batch scale rotative reactor was developed and used as a tool to validate the new heat transfer model [4, 6]. The batch reactor consists of a well insulated tank which contains molten salt and is equipped with heating elements in order to be able to heat the salt to the set point temperature. A second well insulated tank can be placed in the salt bath. The feedstock enters the reactor through the feedpipe. The same agitation blades as those found in the industrial reactor are used. The stirring mechanism transports and agitates the feedstock in a circular manner. The center of the reservoir is kept free of feedstock by a scraping mechanism. The diameter of the feedstock tank is 107 cm and the effective heat transfer area is 0.82 m [6]. 

Jackets, internal helical pipe coils, tube baffles, and plate coil baffles are used to provide heat-transfer surface area. The only surface area effective for heat transfer is that portion that is wetted by both service and process fluids. The effective heat-transfer area for some items may be determined as follows ... 

Selection Double-pipe crystallizer, nominal 8 in. diameter. To consist of 4 sections each 20 ft long each section shall be jacketed for 18 ft of its length. Effective heat-transfer area will be 153 ft total volume 24.9 ft process material retention time 3.33 hr. 

Situation a For products loaded in a two-high configuration on 12" high piers, the effective heat transfer area of the top load(s) would be their full projected top surface area. Because of the thinner gas cloud or blanket adjacent to the lower row of load pieces, their effective heat transfer area would be less. (See fig. 4.7.)... 

Positioning the loads to raise their effective heat transfer area not only improves heat transfer rates but also reduces the lag time (time it takes for the core or lowest %exposed area side to reach the temperature of the hottest surfaces). This benefit reduces thermal stresses in the product, resulting in shorter cycles (less fuel and higher productivity) plus higher quality products. 

Q10. How do enhanced heating burners increase the effective heat transfer area of the product when there is space between the product pieces ... 

AlO. When the spaces between the load pieces are perpendicular to the furnace gas flow, the gases between the loads are practically stationary, so their temperature will stay very near that of the loads. With essentially no temperature difference between these gases and the loads, little if any heat transfer takes place. If energy can be supplied to the stagnant area between the loads by small high-velocity burners (enhanced heating), the effective heat transfer area between the loads and the hearth will increase by more than 25%. 

Heat transfer area. The flooding of the silo with molten salt increases the effective surface area of heat transfer from the reactor vessel to the silo wall. If the silo is full of molten salt, the entire silo wall, not a small section of the wall, rejects heat to the environment. The placement of the reactor core at the very bottom of the reactor vessel allows foil utilization of the complete silo area. Because molten salt heat fluid is used for heat transfer, heat rejection rates can be further increased by (1) increasing silo depth or (2) designing the top of the silo with its shorter pathway for heat rejection to the environment. The effective heat transfer area is thus doubled. 

Outer diameter (mm) Thickness (mm) No. per module Effective heat transfer area per evaporator module (m )... 

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