Novel thermosyphon-assisted setup for determining heat exchanger thermal characteristics

• Published in: Applied thermal engineering 2022-07, Vol.211, p.118315, Article 118315
• Main Authors: de Castro, Felipe R., Cisterna, Luis H.R., Mantelli, Marcia B.H.
• Format: Article
• Language: English
• Subjects: Boilers; Compact heat exchanger; Fanning friction factor; Flow velocity; Fluid flow; Friction factor; Heat conductivity; Heat exchanger thermal-hydraulic characteristics; Heat exchangers; Heat transfer; Nusselt number; Pressure drop; Steady state; Steady-state Kays and London technique; Streams; Temperature; Temperature distribution; Thermal energy; Thermosyphons; Two-phase Thermosyphon; Vapors; Wall temperature; Working fluids
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2022.118315

•A new thermosyphon-assisted setup for heat exchanger thermal test is proposed.•Two phase thermosyphons supply constant wall temperature boundary conditions.•Vapor from thermosyphons is the controlled heat source of tested heat exchangers.•New setup is a simple manageable adaptation of Kays and London classical apparatus.•Data was obtained and used to validate the newly developed experimental setup. To be used in the market, thermal and friction characteristics of newly launched heat exchangers must be acknowledged, usually by experimental methods. Steady-state Kays and London is considered the classical experimental technique. In this setup, one of the heat exchanger streams is usually vapor, to provide controlled known heat transfer and temperature conditions, while the other stream is subjected to different flow rates, for the determination of the equipment thermal and pressure drop behaviors. Large expensive industrial boilers are usually used, resulting in difficulties in stabilizing and controlling vapor temperatures. In the present work, a new experimental setup, based on the above-mentioned technique, is proposed for determining the heat transfer characteristics of compact heat exchangers. The boiler vapor flow is substituted by the working fluid (water in vapor state) of a two-phase thermosyphon. Being smaller and much more flexible, this technology allows for easy control of the vapor temperature, while providing uniform temperature distribution along one of the heat exchanger streams, which is difficult to obtain with the classical procedure. In the proposed apparatus, the “known side” of the heat exchanger takes the role of the condenser of the thermosyphon. Two well-known heat exchanger cores, composed by circular and square cross section channels, were used to validate the proposed arrangement, considering the ranges: 2200