Pulsating heat pipe (PHP)

which is also called oscillating heat pipe (OHP)

is a novel type of highly efficient heat transfer component. It is widely applied in many fields

including aerospace technology

cooling of electronic devices and energy-saving technology

etc. In the present paper

the characteristics and working principles of PHPs are first introduced

and then the current research in the field is described from experimental study

theoretical study and practical application achievements. The experimental investigations are mainly focused on the flow visualization and the applications of nano-fluids and other functional fluids to enhance heat transfer performance of the PHPs. It is also pointed out that the current theoretical analyses of the PHP are restricted by further development of two-phase flow theory

and are concentrated in the non-linear analysis. Numerical simulations will become another research focus

especially the combination of the nano-fluids and functional fluids.