In adiabatic flow, what is assumed about heat transfer?

• A. No heat transfer occurs
• B. Heat transfer is maximal
• C. Heat transfer is independent of process
• D. Heat transfer depends on friction

Answer: (A)

In adiabatic flow, the system is perfectly insulated from its surroundings, so no heat crosses the boundaries. That means the heat transfer term is zero, and any changes in the fluid’s energy come from work done on or by the fluid rather than from heat exchange with the environment. As a result, the temperature can still rise or fall due to compression or expansion, but there is no heat added or removed across the boundaries. In many idealized analyses, this is paired with neglecting viscous dissipation, so the energy change is captured purely by work terms.