What cycle process has constant enthalpy?

What cycle process has constant enthalpy?

• A. Isenthalpic Process
• B. Isobaric Process
• C. Isoenthalpic Process
• D. Isothermal Process

Answer: (A)

Constant enthalpy means the flow energy content of the fluid does not change as it passes through that part of the cycle. Enthalpy, H, combines internal energy and flow work (H = U + pV). In a throttling-type step, there is no heat transfer or shaft work, so the energy balance simplifies to h1 = h2, making the process isenthalpic. This is the defining name for a cycle segment where enthalpy stays the same. Thus, the process described is isenthalpic. By contrast, constant pressure describes isobaric processes, constant temperature describes isothermal processes, and isoenthalpic is simply an alternate spelling of isenthalpic, with the standard term most commonly used being isenthalpic.

Constant enthalpy means the flow energy content of the fluid does not change as it passes through that part of the cycle. Enthalpy, H, combines internal energy and flow work (H = U + pV). In a throttling-type step, there is no heat transfer or shaft work, so the energy balance simplifies to h1 = h2, making the process isenthalpic. This is the defining name for a cycle segment where enthalpy stays the same.

Thus, the process described is isenthalpic. By contrast, constant pressure describes isobaric processes, constant temperature describes isothermal processes, and isoenthalpic is simply an alternate spelling of isenthalpic, with the standard term most commonly used being isenthalpic.