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A Non-Mixing Heat Transfer Apparatus

IP.com Disclosure Number: IPCOM000082911D
Publication Date: 2005-Feb-28
Document File: 4 page(s) / 85K

Publishing Venue

The IP.com Prior Art Database

Abstract

The following article describes the design for a non-mixing type heat transfer apparatus, which can be used for heating or cooling viscous liquids under laminar flow conditions.

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A Non- Mixing Heat Transfer Apparatus

Summary

The following article describes the design for a non-mixing type heat transfer apparatus, which can be used for heating or cooling viscous liquids under laminar flow conditions.

Design Description

The heat transfer apparatus consists of a single large channel, filled with a multitude of circular hollow tubes with or without baffles. The single channel is preferably rectangular but other shapes would work equally well (for high pressure applications a round channel may be considered). The outer and inner surface of the tubes can have fins attached to them for enhancing convective heat transfer. The cooling or heating medium (water, steam or a heat transfer fluid like dowtherm) flows through the tubes and the process fluid (which needs to be heated or cooled) flows through the large channel.

The cooling tubes are arranged in alternate rows of horizontally and vertically oriented tubes, which means that a row of horizontal tubes is followed by a row of vertical tubes and so on along the length of the heat exchanger. The gap between neighboring tubes in a row is preferably the same as the outer diameter of the tubes. The front view of the heat exchanger is shown in Figure 1 below:


Figure 1

Figure 2 below depicts a three dimensional view of the first 4 rows of tubes in the Heat Exchanger, which shows that the 2nd row of vertically oriented tubes (which is the 3rd row of tubes) is staggered from the 1st row of vertically oriented tubes. The tubes in the 3rd row are arranged in such a way that they are in line with the gap between the tubes in the 1st row. Similar arrangement is done for the horizontally oriented tubes in Rows 2 and 4. The pattern of tubes seen in these 1st four rows is repeated in the rest of the heat exchanger. For the design of this heat exchanger, it is immaterial whether the 1st row of tubes is horizontal or vertical.

Figure 2


The arrangement of tubes described above is also clear from the top view of the Heat Exchanger shown below in Figure 3.

Figure 3

The walls of the rectangular outer channel would preferably be manufactured as tube sheets in a conventional heat exchanger. The ends of the cooling tubes would pass through these walls (or tube sheets), where the heating or cooling fluid would be circulated through them using headers. A schematic of a heat exchanger incorporating the ideas listed above is shown below in Figure 4.


Figure 4

The Non-Mixing Heat Exchanger divides the incoming process stream (which is to be heated or cooled) into smaller sub-streams, which do not mix. The Reynolds number of the flow is very low (highly laminar flow regime, Nre ~0.1 to 100), which prevents separation of flow around the surface of the heating/cooling tubes. However, efficient heat transfer is achieved by alternating the orien...