http://home.iitk.ac.in/~samkhan/Bio_data/publications/Khandekar_4.pdf

Closed loop pulsating heat pipes Part B: visualization and semi-empirical modeling

http://home.iitk.ac.in/~joshi/International%20Journal%20of%20Thermal%20Sciences.pdf

Thermal performance of closed two-phase thermosyphon using nanofluids

The use of the two-phase closed thermosyphons (TPCTs) is increasing for many heat transfer applications. This paper reviews the most recent published experimental and theoretical studies on the TPCT. After a description of the TPCT operating principle and the performance characteristics, the heat transfer analysis in condenser and evaporator sections that depends on the complex two-phase process are described. The influence of the affecting parameters on the performance of TPCTs such as the geometry (diameter, shape and length), the inclination angle, the filling ratio (FR), the working fluid, the operating temperature and pressure analyzed by various researchers is discussed. The various operating limits occurring in a thermosyphon includes viscous, sonic, dryout, boiling and flooding are also analyzed. Considering the application of TPCTs, the paper presents a review of experimental tests and applications. This paper can be used as the starting point for the researcher interested in the TPCTs and their renewable energy applications.

Two-phase closed thermosyphons: A review of studies and solar applications

A comprehensive film condensation heat transfer correlation, established on the basis of analytical and empirical results from the literature, is in excellent agreement with all existing data. It incorporates the effects of interfacial shear stress, interfacial waviness, and turbulent transport in the condensate film. The usefulness of this correlation is demonstrated for annular-film condensation inside tubes. This correlation can easily be incorporated into condensing models once the interfacial shear stress is known. Two cases, cocurrent annular-film condensation inside vertical and horizontal tubes and countercurrent annular-film reflux condensation such as occurs inside the two-phase closed thermosyphon, are used to demonstrate this procedure.

General film condensation correlations

Critical heat flux

The present work explores the physical basis for the entrainment limit in heat pipes and attempts to develop adequate quantitative criteria for the limit. Analogy is emphasized here between the entrainment phenomenon in heat pipes and the flooding phenomenon in countercurrent vapor-liquid flow systems. The maximum operating heat-transfer rates for various heat pipes due to entrainment limitation are established semiempirically by way of modifying existing flooding correlations. While the present results are successful in correlating the limited experimental data available, further experimental studies are needed in assessing the validity of the established criteria.

K. S. Chung

Papers

Entrainment Limits in Heat Pipes

Entrainment limits in heat pipes