Question

In recuperators, AMTD refers to:

• A. Average Molecular Thermal Drive
• B. Arithmetic Mean Temperature Difference
• C. Analytical Method of Thermal Distribution
• D. Asymmetrical Mean Temperature Dynamics

Hint:

Use AMTD for quick, approximate heat exchanger sizing where temperature differences at both ends are known and linear profiles are assumed.

Answer 1

The Correct Option is B

Step 1: AMTD stands for Arithmetic Mean Temperature Difference. It is used in heat exchanger design, particularly for recuperators, to represent the average temperature driving force for heat transfer. 
Step 2: It is calculated as the simple arithmetic mean of the temperature differences at the two ends of the heat exchanger: \[ \text{AMTD} = \frac{(\Delta T_1 + \Delta T_2)}{2} \] where \( \Delta T_1 \) and \( \Delta T_2 \) are the temperature differences between the hot and cold fluids at each end. 
Step 3: While the logarithmic mean temperature difference (LMTD) is often more accurate for varying temperature profiles, AMTD is a simpler approximation used in linear systems or for preliminary calculations. 

Why the other options are incorrect:

• (A), (C), and (D) are fabricated terms that do not correspond to any recognized thermal or heat exchanger principles.