Numerical Investigation of Pool Boiling Under Ocean Condition with Lattice Boltzmann Simulation. Part Ⅱ: Rolling Condition

Qifan Zou,Yongyan Hu,Yuxuan Chang,Xiuliang Liu,Pengkun Li

doi:10.3389/fenrg.2021.771781

Qifan Zou, Yongyan Hu + Show 3 more

Open Access

https://doi.org/10.3389/fenrg.2021.771781

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Abstract

Rolling motion caused by ocean condition will induce more complicated inertial forces with their force directions changing all the time, which results more complex bubble behaviors and unique heat transfer characteristics. In this work, pool boiling under rolling condition is numerically simulated using multiple relaxation time phase change lattice Boltzmann method (LBM). Pool boiling patterns, boiling curve of time-averaged heat flux, transient heat flux and rolling effects on different pool boiling regions are investigated. The results show that pool boiling curve of time-averaged heat flux between rolling condition and static condition are not obvious until close to critical heat flux, and 9.3% higher CHF is achieved under rolling condition while worse heat transfer is discovered at film boiling. Moreover, distinct fluctuation of transient heat flux of pool boiling under rolling condition is found for all boiling regimes, and its variation pattern along with the rolling motion and bubble behavior is investigated. Furthermore, tangential inertial force caused by rolling motion has positive influence on heat transfer of pool boiling, while the centrifugal force has negative influence on heat transfer, since it is opposite to the gravity and hence decreases the buoyancy force. Besides, larger rolling amplitude and smaller rolling period will induce larger additional inertial forces, and thus make greater influences on the bubbles’ behavior and pool boiling heat transfer.

Highlights

Exploitation and utilization of ocean resources have been one of most promising directions of clean energy development, and investigations of marine power applications using steam-water power cycle with phase change have received more and more attentions (Yan, 2017; Wang et al, 2019; Tian et al, 2020)
Heat transfer characteristics of pool boiling under rolling condition is analyzed, and the results have been made comparison with that under static condition
The following conclusions can be drawn from this paper: 1) Bubble behaviors under rolling condition is totally different from that under static condition, which goes through the process of nucleation, growth, sliding, coalescence, departure and swinging rising

Summary

INTRODUCTION

Exploitation and utilization of ocean resources have been one of most promising directions of clean energy development, and investigations of marine power applications using steam-water power cycle with phase change (boiling and condensation) have received more and more attentions (Yan, 2017; Wang et al, 2019; Tian et al, 2020). (Ren et al, 2018) presented that the time-averaged HTC of flow boiling was enhanced by 31.33–115.43%, and the enhancement intensity increased with the aggrandizement of rolling angle and the decrease of rolling period Both CHF and HTC have been influenced by the bubble behaviors, such as bubble nucleation, bubble growth, departure, sliding, distribution and movement, which have investigated a lot in flow boiling. Lattice Boltzmann method (LBM) has received extensive attention and has been developed to simulate multiphase flow (Huang et al, 2019; Huang et al, 2021) and phase change heat transfer (boiling, evaporation, condensation, etc.) (Cheng et al, 2014; Li et al, 2016), which could investigated CHF, HTC and bubble behaviors of pool boiling effectively.

RESULTS AND DISCUSSION

CONCLUDING REMARKS

DATA AVAILABILITY STATEMENT