Allowing a gas vapor to expand through an extremely tiny opening is referred to as__________________?
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Answer: E. throttling
Explanation
Throttling involves expanding a gas or vapor through a tiny orifice without external work transfer. This process is isenthalpic, meaning the enthalpy remains constant before and after the restriction. Passing fluid through a porous plug or valve is the classic definition of throttling. Throttling devices include expansion valves, porous plugs, and partially opened control valves. During throttling, fluid pressure drops significantly while kinetic energy changes are often negligible. Joule-Thomson effects describe the temperature change experienced by gases during throttling.
Refrigeration systems utilize expansion valves to throttle high-pressure liquid refrigerant into low pressure. Power plants use throttling valves to regulate steam flow rates entering turbine stages. Understanding throttling helps engineers control fluid pressures safely in industrial piping networks. Option A refers to free expansion into an evacuated chamber, which differs from steady throttling. Option B describes polytropic expansion following a hyperbolic pressure-volume path. Option C involves reversible adiabatic expansion producing external work, unlike throttling.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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