B. Borgmeyer

TL;DR: By combining nanofluids with thermally excited oscillating motion in an oscillating heat pipe (OHP), Wang et al. as mentioned in this paper developed an ultrahighperformance cooling device, called the nanoffluid oscillating pipe.

TL;DR: In this article, a mathematical model predicting the oscillating motion in an oscillating heat pipe is developed, where the model considers the vapor bubble as the gas spring for oscillating motions including effects of operating temperature, nonlinear vapor bulk modulus, and temperature difference between the evaporator and the condenser.

TL;DR: In this article, a detailed mathematical model predicting fluid flow and heat transfer through the thin film region is developed, considering the effects of inertial force, disjoining pressure, surface tension, and curvature.

Abstract: An experimental study was conducted to evaluate the motion of vapor bubbles and liquid plugs within a flat plate pulsating heat pipe to determine the effects of working fluids (water, ethanol, Flutec PP2, and Flourinert), power input, filling ratio, and angle of orientation on the pulsating fluid flow. Experimental investigations quantify the position and velocity of the liquid-vapor interface for various conditions. Through the use of a Photron high speed camera, precise locations of the liquid-vapor interface were tracked and analyzed. Experimental data show that both the macromovement and oscillating motion of vapor bubbles and liquid plugs exist for a functional pulsating heat pipe. The amplitude of these oscillations was increased as more power was inputted into the pulsating heat pipe. The pulsating heat pipe investigated here would not function when charged with 50% high performance liquid chromatography grade water and positioned horizontally. On the other hand, the experimental results show that when the heat pipe was charged with ethanol, it created the largest amplitudes and velocities. The oscillating motion of vapor bubbles and liquid plugs including the macromovement is very sensitive to the tilted angle, and large increases in amplitude were observed when the angle was increased (bottom heating mode) from horizontal.

TL;DR: In this paper, a flow visualization was conducted on an 8-turn water oscillating heat pipe, a 12-turn nanofluid oscillating pipe, and a 8turn heat pipe with high performance liquid chromatography grade water.