Effect of Operational Parameters on the Thermal Performance of Flat Plate Oscillating Heat Pipe

Abstract

Flat plate oscillating heat pipe (FP-OHP) is a unique heat transfer device and considered as a promising candidate for effective heat transfer device in electronics industries. A number of theoretical studies and experimental investigations have been carried out on FP-OHP in the past decades after its invention. However, due to the operational characteristics of FP-OHP, the effect of various parameters on the thermal performance of FP-OHP has not been completely revealed so far. This paper attempts to discuss the effect of operational parameters on the thermal performance of FP-OHP. In this study, the FP-OHP was investigated with different charge ratios, orientations, working fluids, and heat loads from 10 W to 150 W. In order to investigate the effect, 18 parallel square channels of 2 × 2 mm2 are machined onto pure copper plate (93 × 70 × 8 mm3) to form FP-OHP. DI water, ethanol, methanol, acetone, and FC-72 are investigated. The measured thermal resistance was strongly dependent on operational parameters. The optimum performance was observed with acetone with a charge ratio of 70% in the vertical orientation. The lowest thermal resistance of 0.39 °C/W is achieved using acetone as a working fluid at 100 W. A Kutateladze number (Ku) was used to compare the experimental data and found to be suitable for prediction of the thermal performance of FP-OHP with standard deviation of 15%.

Influence of the channel profile on the thermal resistance of closed-loop flat-plate oscillating heat pipe

“…The dimensions and details of the test section are shown in Figs. 3 [28,47] and 4. The hydraulic radius of the CL-FPOHP channel must be small enough so that the surface tension force overcomes the gravity force to develop two-phase flow within the CL-FPOHP.…”

“…The CL-FPOHP experimental setup is shown in Fig. 5 [47]. The experimental setup consists of a CL-FPOHP test section, heat load input system, water supply, temperature scanner, USB 485 coveter, laptop and stand.…”

“…In addition to the experimental investigations, many theoretical studies have also been suggested to know heat transfer mechanism in CL-FPOHP [44][45][46]. However, the thermal performance of CL-FPOHP is affected by many parameters, which can be divided into two groups: (1) geometrical side parameters; channel shape, size of channels, (2) operational side parameters; charge ratio, orientation, working fluid and heat load [47]. In existing literature, quite a good number of experimental investigations on operational parameters and flow visualization studies of CL-FPOHP are reported [48][49][50][51].…”

“…Experimental, numerical and theoretical works are done by many researchers; however, complete knowledge on its function, thermal performance and operation is yet to be achieved. Experimental investigations are mainly focused on the effects of operational side parameters on certain model of CL-FPOHP [47]. Such investigations are performed to understand the quantitative effects of thermodynamic, physical and operating condition on the thermal performance of CL-FPOHP.…”

Device‐Scale Nanochannel Evaporator for High Heat Flux Dissipation

“…Although water offers high surface tension and high latent heat relative to its viscosity, the choice of a low-viscosity working fluid is desirable for electronics applications and can even perform better than water. [20] Among these fluids, 3M Fluorinert electronic liquid FC72 with its dielectric properties, has been found to be a suitable working fluid in oscillating heat pipes [31,32] and has demonstrated superior heat transfer performance over water using gas-assisted thin film evaporation. [33] At lower film thickness, the volatility benefit of FC72 over water plays a critical role in attaining a relatively higher heat flux even with its low thermal conductivity.…”