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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 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 ...
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.
If you bought a non-current asset for $10,000 and have written off $3,000 for depreciation, the current valuation of that non-current asset is $7,000. Examples of Non-Current Assets in Major Companies
Three-dimensional plot showing the values of the logarithmic mean. In mathematics, the logarithmic mean is a function of two non-negative numbers which is equal to their difference divided by the logarithm of their quotient. This calculation is applicable in engineering problems involving heat and mass transfer.
Two fluids, of different starting temperatures, flow through the heat exchanger. One flows through all the tubes in parallel and the other flows outside the tubes, but inside the shell, typically in counterflow. Heat is transferred from one fluid to the other through the tube walls, either from tube side to shell side or vice versa.
The total rate of heat transfer between the hot and cold fluids passing through a plate heat exchanger may be expressed as: Q = UA∆Tm where U is the Overall heat transfer coefficient, A is the total plate area, and ∆Tm is the Log mean temperature difference. U is dependent upon the heat transfer coefficients in the hot and cold streams. [2]
The agency also says to wash fruits and vegetables thoroughly before consuming them, and to cook oysters and other shellfish to an internal temperature of at least 145°F, which is the temperature ...