CT: The general function of a heat exchanger is to transfer heat from one fluid to another. The basic component of a heat exchanger can be viewed as a tube with one fluid running through it and another fluid flowing by on the outside. There are thus three heat transfer operations that need to be described:
- Convective heat transfer from fluid to the inner wall of the tube,
- Conductive heat transfer through the tube wall, and
- Convective heat transfer from the outer tube wall to the outside fluid.
Heat exchangers are typically classified according to flow arrangement and type of construction. The simplest heat exchanger is one for which the hot and cold fluids move in the same or opposite directions in a concentric tube (or double-pipe) construction. In the parallel-flow arrangement of Figure 18.8(a), the hot and cold fluids enter at the same end, flow in the same direction, and leave at the same end. In the counterflow arrangement of Figure 18.8(b), the fluids enter at opposite ends, flow in opposite directions, and leave at opposite ends.
S: http://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node131.html (last access: 23 December 2014)
N: 1. heat (n): Old English hætu, hæto “heat, warmth; fervor ardor,” from Proto-Germanic haita- “heat”, from PIE kaid-, from root kai- “heat.” The same root is the source of Old English hat “hot” and hæða “hot weather”.
exchanger (n): O. Fr. eschangier (Fr. échanger)—Low L. excambiāre—L. ex, out, cambīre, to barter.
From exchange (n.), late 14c., “act of reciprocal giving and receiving,” from Anglo-French eschaunge, Old French eschange (Modern French échange), from Late Latin excambium, from excambiare, from Latin ex- “out” + cambire “barter”).
2. Device used to transfer heat from one material to another, usually between two separate fluids.
3. In the heat exchanger of an emulsion-treating unit, heat from the outgoing clean oil is transferred to the incoming well fluid, thus cooling the clean oil and heating the incoming well fluid.
4. Heat exchangers must be able to withstand corrosion and avoid the contamination that can occur in a functioning PEM fuel cell.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=heat+exchanger&searchmode=none; http://www.etymonline.com/index.php?term=exchange (last access: 23 December 2014); http://www.finedictionary.com/exchanger.html (Chambers’s Twentieth Century Dictionary) (last access: 23 December 2014). 2, 3 & 4. TERMIUMPLUS.
SYN: exchanger, thermal exchanger.