Irreversibility in Throttling — Effect of Pressure Drop Magnitude Consider a throttling (adiabatic, no-shaft-work) process of a real fluid through a restriction. Is the following statement correct? “The greater the pressure difference across the throttle, the lesser is the irreversibility.”

Introduction:
Throttling is a widely used expansion in valves and capillary tubes. It is inherently irreversible because pressure drops at essentially constant enthalpy with significant entropy generation. The claim suggests irreversibility decreases as pressure drop increases, which contradicts thermodynamic reasoning.

Given Data / Assumptions:

• Steady-flow throttling: adiabatic, no shaft work, negligible changes in kinetic and potential energies (usually).
• Real fluid behavior; Joule–Thomson effects may change temperature but not enthalpy.
• Irreversibility measured by entropy generation s_gen > 0.

Concept / Approach:
For throttling, the second law indicates s_out - s_in = s_gen (adiabatic, no heat transfer). Larger pressure drops at similar inlet states commonly increase viscous dissipation and mixing, raising s_gen. Hence, greater pressure difference generally means more irreversibility, not less.

Step-by-Step Solution:
Model as an adiabatic, steady-flow control volume with one inlet and one outlet.Apply first law: h_out ≈ h_in (enthalpy approximately constant).Apply second law: s_out - s_in = s_gen ≥ 0; stronger throttling raises s_gen due to larger dissipative losses.Therefore, the statement is false.

Verification / Alternative check:
Refrigeration expansion valves show increased entropy and lost work potential as the pressure ratio increases, matching the qualitative conclusion.

Why Other Options Are Wrong:
Answering “Yes” would invert the entropy-generation trend for throttling and misrepresent second-law behavior.

Common Pitfalls:
Confusing throttling with isentropic expansion through a turbine (which would produce work and lower entropy ideally); assuming larger pressure drop always yields more cooling without acknowledging irreversibility.

Final Answer:
No