Hydraulic Performance of Small Bending Radius Helical Coil-Pipe

TLDR

Helical steam generators and heat exchangers are widely used in high‑temperature gas cooling reactors, fast breeder reactors, pressurized water reactors, ship propulsion, and the electro‑power, chemical, and petroleum industries. This study investigates the hydraulic performance of small‑bending‑radius helical coil pipes in the HTR‑10 reactor. Experiments were performed on the HTR‑10 steam generator experimental facility to evaluate flow behavior in these coils. Results show that the critical Reynolds number for helical pipes is much higher than for straight pipes and depends on the diameter ratio, and the authors derived formulas for transition Reynolds number, friction coefficient, and two‑phase friction factor, which are recommended for design. Keywords: hydraulic performance, small‑bending‑radius helical pipe, single‑phase flow, two‑phase flow, friction, fluid flow, helical pipe design.

Abstract

Abstract Helical steam generator or helical heat exchanger is extensively used in high-temperature gas cooling reactor, fast breeder reactor, pressurized water reactor using in ship propulsion and areas of electro-power, chemical industry and petroleum industry. The purpose of this paper is to research the hydraulic performance of small bending radius helical coil-pipe used in HTR-10. Research for hydraulic performance of small bending radius helical pipe was carried out on the HTR-10 steam generator experimental facility. Based on the experimental results, it was confirmed that for helical pipe the critical Reynolds number (Re) is much greater than in a straight pipe and is a function of De. Formulas for Re of single-phase flow structure transition, friction coefficient of single-phase flow, and two-phase flow friction factor are obtained. Experience formulas of small bending radius helical pipe are recommended for design and research. KEYWORDS: hydraulic performancesmall bending radius helical pipesingle-phase flowtwo-phase flowfrictionfluid flowhelical pipedesign