Are All Adiabatic Processes Isentropic?

Isentropic process: entropy is a constant, Ds=0. A reversible, adiabatic process is always isentropic since no entropy generation due to irreversibilities (sgen=0) and no change of entropy due to heat transfer (ds=? Q/T=0).

Why adiabatic process is not isentropic?

So generally an adiabatic process is not necessarily isentropic -- only if the process is reversible and adiabatic we can call it isentropic. For example a real compressor can be assumed adiabatic but is operating with losses. Due to the losses the compression is irreversible. Thus the compression is not isentropic.

Are all adiabatic process Isenthalpic?

An adiabatic process is one where there is no non-work interactions at the boundary (i.e. heat interactions). ... As long as the process maintains the same enthalpy with or without boundary interactions, it is considered isenthalpic.