What is physical significance of NTU?

The Number of Transfer Units (NTU) Method is used to calculate the rate of heat transfer in heat exchangers (especially counter current exchangers) when there is insufficient information to calculate the Log-Mean Temperature Difference (LMTD).

What does NTU mean in heat transfer?

number of transfer units
Two methods are normally used for sizing and rating heat exchangers: effectiveness–number of transfer units (NTU) method and logarithmic mean temperature difference (LMTD) method.

What is the physical significance of Nusselt number and Prandtl number?

Nusselt number is a measure of the ratio between heat transfer by convection (α) and heat transfer by conduction alone (λ/L). Convective heat transfer relationships are usually expressed in terms of Nusselt number as a function of Reynolds Number and Prandtl Number.

What is the physical significance of the Prandtl number does the value of the Prandtl number depend on the type of flow or the flow geometry?

The Prandtl number is a fluid property that does not depend on the type of flow or flow geometry. The values of , cp and k are known to change with temperature so the Prandtl number will change with temperature.

What is the NTU method for heat transfer?

NTU method. (Redirected from NTU Method) Jump to navigation Jump to search. The Number of Transfer Units (NTU) Method is used to calculate the rate of heat transfer in heat exchangers (especially counter current exchangers) when there is insufficient information to calculate the Log-Mean Temperature Difference (LMTD).

What does NTU stand for?

The Number of Transfer Units (NTU) Method is used to calculate the rate of heat transfer in heat exchangers (especially counter current exchangers) when there is insufficient information to calculate the Log-Mean Temperature Difference (LMTD).

What is the effectiveness-NTU method?

Similar to sensible-only heat exchangers, effectiveness-NTU (ɛ-NTU) methods are also convenient for analysis of heat and mass exchangers. They provide a simple way to build the relations between heat and mass transfer performance and the geometric, physical and operating conditions of heat and mass exchangers.

How does the number of transfer units affect the heat exchanger performance?

As in sensible-only heat exchangers, the number of transfer units, NTU, has a great influence on the system performance. There are many ways to modify NTU. When the wheel mass and channel size are fixed, changing the wall thickness will change the channel numbers, and consequently the contact area and NTU.