铅铋合金/硅酸锆颗粒双介质相变储热性能及演化规律数值研究

Numerical study on the heat storage performance and evolution law of lead-bismuth alloy/zirconium silicate particles dual-media phase change

随着我国新能源电力装机容量大幅提升,大型燃煤机组迫切需要提高灵活运行和深度调峰能力,而利用高温蒸汽热量进行适时存储/释放是提高机组调峰能力的有效方法。为了提高高温储/放热过程速率及性能,本文提出了基于液态金属/硅酸锆颗粒的新型双介质储热体系,建立了铅铋合金/硅酸锆双介质储热过程数理模型,数值研究了铅铋合金与硅酸锆颗粒储热性能及其储热过程瞬态演化规律,比较了纯液态金属和不同硅酸锆颗粒填充比时相变储热过程特征。结果表明相同体积下,纯铅铋合金、29%、34%、38%、42%、50%六种填充比模型的熔化时间分别为202、167、164、161、158、151 s,储热量分别为18547、20474、20670、20845、21001、21254 J。双介质体系与纯铅铋合金相比熔化时间最大缩短25.2%,蓄热量最大提高14.6%。与纯液态金属储热相比,双介质储热体系具有吸热速度快、储热量大,成本低等优点,具有较好的经济效益和应用价值。

With the significant increase in the installed capacity of new energy power in China,there is an urgent need for large coal-fired units to improve their flexible operation and deep peaking capability,and the use of high-temperature steam heat for storage/release at the right time is an effective method to improve the peaking capability of the units.In order to improve the rate and performance of high-temperature heat storage/release process,this paper proposes a new dual-media heat storage system based on liquid metal/zirconium silicate particles,establishes a mathematical model of lead-bismuth alloy/zirconium silicate dual-media heat storage process,numerically researches the heat storage performance of the leadbismuth alloy and the zirconium silicate particles as well as their transient evolution of heat storage process,and compares the characteristics of the phase-change heat storage process between the pure liquid metal and the zirconium silicate particles with different filling ratios.The results show that under the same volume,the melting time of the six filling ratio models of pure lead-bismuth alloy(0%),29%,34%,38%,42%and 50%was 202,167,164,161,158,151 s,and the heat storage was 18547,20474,20670,20845,21001 and 21254 J,respectively.The melting time of the dual-media system is shortened by 25.2%and the heat storage capacity is increased by 14.6%compared with that of the pure lead-bismuth alloy.Compared with pure liquid metal heat storage,the dual-media heat storage system has the advantages of fast heat absorption,large heat storage capacity and low cost,which has better economic benefits and application value.