ABSTRACT

Waste heat sources in industrial processes, transport sectors and solar energy generally possess fluctuating and intermittent nature, which presents a great challenge to the steady operation of Organic Rankine Cycle (ORC). Thus, a parametric study is conduced to investigate the dynamic behaviors of basic Organic Rankine Cycle under fluctuating heat source. Firstly, the dynamic simulation model of basic ORC was established based on the moving boundary method. Then the effects of thermal capacity (ρc_p ) of evaporator and ratio of cross-section area (A_i/A_o ) of two channels for working fluid and heat source are evaluated on the step response characteristics of basic ORC. Finally, the fluctuating heat sources are assumed as a series of sinusoidal waves, and the effects of period and amplitude of fluctuating heat sources are analyzed on the characteristics of continuous operation of basic ORC. The results indicate that the response speed of evaporating pressure and superheat degree decrease with the increase of the area ratio A_i/A_o and thermal capacity ρc_p , but A_i/A_o is the dominant impactor. As for the results of continuous operation under fluctuating heat sources, it is found that the minimum superheat degree decreases with the increase of the period and amplitude of fluctuating heat sources under a fixed A_i/A_o . When the area ratio A_i/A_o increases from 0.36 to 0.60, the maximum allowable amplitude of fluctuating heat source is improved within small-period range, and it showed a reverse trend within large-period range.

摘要

工业过程，运输部门和太阳能中的废热源通常具有波动性和间歇性，这对有机朗肯循环（ORC）的稳定运行提出了巨大挑战。因此，进行了参数研究以研究基本有机朗肯循环在热源波动下的动力学行为。首先，基于运动边界法建立了基本ORC的动态仿真模型。然后的热容量的影响（ρC _p 蒸发器和横截面面积的比率（的）甲_我/ A _ö 根据基本ORC的阶跃响应特性评估了工作流体和热源两个通道的）。最后，将波动热源假定为一系列正弦波，并分析波动热源的周期和幅度对基本ORC连续运行特性的影响。结果表明，蒸发压力和过热度降低与面积比的增加的响应速度甲_我/ A _ö 和热容量率ρc _p ，但甲_我/ A _ö 是主要的影响者。至于在波动的热源下连续运行的结果，发现最小的过热度随着波动的热源在固定的A _i / A _o 下的周期和幅度的增加而降低。当面积比A _i / A _o 从0.36增加到0.60时，波动热源的最大允许幅度在小时期范围内得到改善，并且在大时期范围内呈现出相反的趋势。