###### Abstract  
Although uncertainties such as solar radiation and material properties are generally involved in the solar receiver design process, current studies in the solar receiver field are based on deterministic models and do not incorporate these uncertainties into the design process. In this paper, based on a coupled deterministic thermal-structural model and an uncertainty analysis model, an analysis of temperature and thermal stress was conducted for a solar power tower (SPT) molten salt receiver under multi-source uncertainties to investigate the dispersions of responses. The results demonstrated that the maximum temperature inside the tube wall under multi-source uncertainties ranged from 847 K to 895 K, with an expectation of 871 K and a standard deviation of 8 K, and the maximum thermal stress ranged from 173 MPa to 245 MPa, with an expectation of 204 MPa and a standard deviation of 12 MPa, both of which had severer probabilities than the deterministic results (871 K and 204 MPa) and may cause failure in the receiver. Furthermore, the results of the global sensitivity analysis indicated that the peak incident solar flux was the most sensitive, and the specific heat of the tube material was the least sensitive to the maximum temperature and thermal stress of the tube wall. These results are beneficial to provide additional reliability and confidence in the temperature and thermal stress evaluation process of solar receiver tubes. solar power tower receiver; coupled thermal-structural analysis; uncertainty propagation; probability distribution; global sensitivity analysis +
Footnote †: journal: Applied Sciences
by theoretical equations may not be accurate enough when the axial and circumferential temperature gradients cannot be neglected, compared with the radial temperature gradient. To solve this problem, some researchers recently employed the finite element method (FEM) to obtain the thermal stress distribution of the receiver tube wall [15; 16; 17; 18; 19]. [PERSON] et al. [15] performed a coupled fluid-thermal-structural analysis to acquire the thermal stress distribution of the SPT receiver. The heat transfer process is numerically simulated with FVM, which is used to calculate the thermal stress. [PERSON] et al. [16] also obtained the radial, circumferential, and axial stresses throughout the tube by using the ANSYS Structural software based on the temperature distribution solution using ANSYS Fluent. The studies mentioned above were based on deterministic models with unchanged input parameters. However, uncertainties such as solar radiation and material properties widely exist in the operation process of the receiver, and input parameters should be assigned with probability distributions. For instance, the peak solar flux on the receiver tube wall is a typical uncertain parameter and is generally decided by the level of direct normal irradiance, which is assigned as a normal probability distribution with a square deviation of 5.4% [20; 21]. Another important uncertain parameter is the property of the receiver tube wall material, such as absorptance, which is affected by measurement error and performance degradation during long-term use [22]. The receiver tube wall absorptance is assigned as a uniform probability distribution with a range between 0.91 and 0.95 [22; 23]. In addition, other input parameters, such as the thermophysical properties of the heat transfer fluid inside the tube, usually deviate from the nominal values [24]. Furthermore, the uncertainties of the input parameters may lead to the dispersions of the temperature and thermal stress inside the receiver tube wall, which may be more severe than the deterministic results. [PERSON] [8] pointed out that molten nitrate salts become corrosive at higher temperatures of the receiver tube wall and receiver fatigue failure occurs with higher thermal stress in the tube wall.