中文摘要：

直接蒸汽发电（direct steam generation，DSG）槽式太阳能热发电系统的集热器长度一般很长，且具有明显的分布参数特征。因此，建立DSG槽式太阳能集热器的非线性分布参数模型，以DSG集热器入口工质温度、质量流量和出口压力为边界条件，采用迎风格式的有限差分法对模型进行离散求解。仿真研究了DSG集热器主要参数在太阳辐射强度、给水温度和给水流量变化等扰动工况下的响应特性，结果与文献实验结果基本一致，验证了模型的正确性。结果表明：太阳辐射强度降低时，出口工质温度下降得很快：给水流量或给水温度小幅下降时，出口工质温度和流量都会滞后响应且变化显著；DSG集热器出口工质流量在某些情况下会发生脉动，实际应用中应避免脉动状态的发生或降低其影响。

英文摘要：

Direct steam generation （DSG） in parabolic trough solar power system has long solar collector and obvious distributed parameter characteristics. Therefore, a nonlinear distributed parameter model for parabolic trough DSG solar collectors was built in this paper. As a boundary condition, fluid temperature and mass flow had to be provided at the inlet as well as the pressure at the outlet, and the finite differential approach with an upwind scheme was adopted to discrete and solve the model. Compared with experimental results from the literature, the correctness of the model was validated by simulation results during the main conditions such as solar radiation intensity, inlet fluid temperature and inlet mass flow change. Simulation results show that fluid temperature at the outlet decreases quickly when solar radiation intensity is declined; Furthermore, the responses of fluid temperature and mass flow at the outlet delay largely and stabilize slowly when mass flow or temperature at the inlet declined slightly; Most significantly, a pulsation phenomenon of outlet mass flow may happen in some conditions, which should be avoided or declined in practical application.