RanqueHilsch

The Ranque-Hilsch vortex tube is a device that separates compressed gas into hot and cold streams without moving parts. It was developed by Georges J. Ranque in the 1920s and later independently studied by Rudolf Hilsch in the 1940s. In operation, compressed gas is introduced tangentially into a hollow tube, creating a high-speed swirl. A portion of the gas is directed toward a cold outlet at the tube’s rear end, forming a cold stream, while the remaining gas forms a hot outer stream that exits from the opposite end. The exact mechanism is the subject of ongoing discussion, but practical designs rely on flow separation and internal baffling to establish two coaxial streams with different temperatures.

Construction and basic design typically involve a cylindrical metal tube with a cold-end plug or baffle, a restricted cold outlet, and a hot outlet at the opposite end. A gas inlet pressure regulator and an adjustable valve control the amount of gas directed to the cold channel, thereby setting the cold fraction and temperature drop achievable.

Performance and use: The device provides cooling by producing a sub-ambient cold stream and a hot stream whose temperature rises above ambient. The degree of cooling depends on inlet pressure, gas properties, and the fraction diverted to the cold outlet. Vortex tubes have no moving parts, are robust, and are used for spot cooling in electronics, plastics processing, laboratory equipment, and other applications where compressed gas is readily available and electricity for traditional refrigeration is impractical. They are generally less energy-efficient than conventional refrigeration but offer simplicity and reliability in niche cooling tasks.

Variants exist, including multi-tube or staged designs, which aim to improve cooling capacity or control the cold fraction.