Search results
Results from the WOW.Com Content Network
The number of transfer units (NTU) method is used to calculate the rate of heat transfer in heat exchangers (especially parallel flow, counter current, and cross-flow exchangers) when there is insufficient information to calculate the log mean temperature difference (LMTD). Alternatively, this method is useful for determining the expected heat ...
In thermal engineering, the logarithmic mean temperature difference (LMTD) is used to determine the temperature driving force for heat transfer in flow systems, most notably in heat exchangers. The LMTD is a logarithmic average of the temperature difference between the hot and cold feeds at each end of the double pipe exchanger.
The driving temperature across the heat transfer surface varies with position, but an appropriate mean temperature can be defined. In most simple systems this is the "log mean temperature difference" (LMTD). Sometimes direct knowledge of the LMTD is not available and the NTU method is used.
While both co and counter configurations are possible, the countercurrent method is more common. The preference is to pass the hot fluid through the inner tube to reduce heat losses, while the annulus is reserved for the high viscosity stream to limit the pressure drop. Beyond double stream heat exchangers, designs involving triple (or more ...
A shell-and-tube heat exchanger is a class of heat exchanger designs. [1] [2] It is the most common type of heat exchanger in oil refineries and other large chemical processes, and is suited for higher-pressure applications. As its name implies, this type of heat exchanger consists of a shell (a large pressure vessel) with a bundle of tubes ...
The Drake Passage, between the southern tip of South America and Antarctic, is infamous as one of the most dangerous journeys on the planet. But why is it so rough – and how can you cross safely?
A popular member of the Texas Longhorns’ contingent won’t be able to attend the Southeastern Conference championship game on Saturday in Atlanta.
It's probably clearer to express the LMTD in terms of temperatures for 'left' and 'right' ends of the HE. This way the same formula applies to both co- and counter-current systems, and also the cross-flow case. Need to explain that the LMTD follows from a simple 1-D analysis (Incropera & DeWitt 4th Ed, sec 11.3.1).