Evaluation of solar temperature field under different wind speeds for Shanghai 65 m radio telescope

Qian, Hongliang; Chen, Deshen; Fan, Feng; Liu, Ye; Shen, Shihui

doi:10.1007/s13296-016-6011-3

Cited by 15 publications

(6 citation statements)

References 7 publications

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“…where T a is the temperature of ambient air, ∆T g is a temperature offset and it can be approximately expressed as 10 sin[(t − 8)π/12] here (Qian et al 2016), and t is the local time. In addition, considering the white paint surface layer of the alidade, the solar absorption rate of T i m e ( h )…”

Section: Fe Model and Boundary Conditionsmentioning

confidence: 99%

Effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope

Wei

Kong

Wang

2021

Res. Astron. Astrophys.

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The alidade’s non-uniform temperature field of a large radio telescope is very obvious under solar radiation. Estimating a radio telescope’s pointing errors, caused by the alidade deformation under solar radiation, is significant to improve the telescope’s pointing accuracy. To study the effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope, a temperature experiment is first carried out in a 70-m radio telescope on a sunny day. According to the measured results, the temperature distribution rule of the alidade is summarized initially. In addition, the alidade’s temperature field is calculated by finite element thermal analysis. The simulated results are proved to be in good agreement with the experimental results. Finally, the alidade deformation under solar radiation is computed by finite element thermal-structure coupling analysis. The telescope’s pointing errors caused by alidade deformation are estimated via the alidade’s node displacements. The final results show that the effect of alidade thermal behavior on the telescope’s elevation pointing errors Δ ε 2 + Δ εr is much more than the effect on the telescope’s cross-elevation pointing errors Δ ε 1. The maximum of Δ ε 2 + Δ εr is more than 45″, while the maximum of Δ ε 1 is less than 6″. This study can provide valuable references for improving the pointing accuracy of large radio telescopes.

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Section: Fe Model and Boundary Conditionsmentioning

confidence: 99%

Effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope

Wei

Kong

Wang

2021

Res. Astron. Astrophys.

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“…The construction materials of movable radio telescopes mainly include steel and aluminum, which have good thermal conductivity and large specific heat capacity, so the effects of solar radiation and wind on the temperature fields of telescopes should be considered, and the adverse effects of temperature deformation on reflector surface precision and pointing accuracy must be effectively controlled in order to guarantee good observational performance [79]. Qian studied the temperature field and solar cooker effect of the Shanghai 65 m Radio Telescope under different working conditions through model experiments and numerical simulations for several years [80,81]. The non-uniformity of the Shanghai 65 m Radio Telescope's temperature filed under solar radiation is reflected in the back-up and reflector structure, and the non-uniform structural temperature deformation leads to the geometric shape of the telescope during its service period being different from its designed shape, resulting in possible observation errors [82].…”

Section: Radio Telescopesmentioning

confidence: 99%

Non-Uniform Temperature Fields and Effects of Steel Structures: Review and Outlook

Chen

Qian

2020

Applied Sciences

Self Cite

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Due to the dynamic coupling effects of solar radiation, longwave radiation, convective heat transfer, shadows, and other factors, the temperature field and effect of steel structures are significantly non-uniform, differing from traditional concepts that regard the temperature variation of steel structures as a slow and uniform progress. This difference can hinder the correct understanding of the thermal behavior of steel structures and ignore some potential safety hazards. This paper provides a review of the studies for the non-uniform temperature field and effect of steel structures, and presents some outlooks on future developments on the basis of the current research situation. A summary of research on the temperature field and effect of space structures, bridges and radio telescopes initially establishes the basic cognitive framework for this field. In addition, then, the basic principles of the numerical simulation of temperature fields are introduced through heat transfer mechanism, and the experimental test methods of temperature and its effects are described based on typical test cases. Finally, with a view to the future, some suggestions and opinions are provided in consideration of deficiencies in the current research status. This paper hopes to provide some valuable references for future research in this field through research summary, method introduction and outlook.

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“…Over the past decades, the thermal behaviors of many foreign radio telescopes have been studied overseas via combining finite-element (FE) calculations and relative experiments, including the thermal deformation of the reflector system of the RT-70 radio telescope [9], the thermal design of the quadripod and backup structure of the IRAM 30-m telescope [10], and the thermal analysis of the alidade of the Medicina 32-m telescope and the Sardinia 64-m telescope [11][12][13]. In recent years, the thermal behaviors of several domestic radio telescopes also have been researched in China based on FE analysis and experimental measurements, such as the thermal effects of the alidade of the Nanshan 25-m radio telescope and the Miyun 50-m radio telescope [14,15], the nonuniform temperature and the thermal behavior of the Tianma 65-m radio telescope [16,17], the thermal deformations of the alidade and the reflector system of WRT70 [18,19]. To sum up, extensive studies on the thermal behaviors of radio telescopes have been done, but the research on estimating the total pointing error caused by the thermal behaviors of large radio telescopes is poor.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Pointing Errors of Large Radio Telescopes under Solar Radiation Based on Digital Twin

Wei,

Kong,

Wang

et al. 2024

Preprint

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The pointing accuracy of large radio telescopes is affected by antenna structure errors, installation errors, servo errors, gravity, and varying environmental factors. It is hard to estimate the pointing error of radio telescopes under solar radiation via the traditional multi-parameter static pointing models, due to the time-varying characteristics of the dynamic pointing error. There is still no effective way to estimate the dynamic pointing error of large radio telescopes under solar radiation up to now. To estimate the dynamic pointing error of large radio telescopes under solar radiation, a new way based on digital twin(DT) is tried in this paper. The operational framework of the DT system of large radio telescopes is introduced first. Then, the Wuqing 70-m radio telescope(WRT70) is taken as the research object, the digital models of which are created. Finally, the reliability of the WRT70's DT system is verified and the dynamic pointing error of WRT70(staying at the position of the elevation angle of 90° and the azimuth angle of 180°) on two sunny days in different seasons is estimated by the created DT system. The research results show that the pointing error of large radio telescopes under solar radiation fluctuates greatly and the seasonal differences are very striking. The maximum elevation pointing error of WRT70 under solar radiation around the winter solstice is over 40 arcsec, which should never be ignored. The way is feasible to estimate the dynamic pointing error of large radio telescopes staying at a specific position under solar radiation via constructing a DT system in this paper, but it is not yet able to estimate effectively the dynamic pointing error of large radio telescopes being in action. It is expected to establish a dynamic pointing error model and calibrate the dynamic pointing errors of large radio telescopes being in action by DT technology in the future.

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Evaluation of solar temperature field under different wind speeds for Shanghai 65 m radio telescope

Cited by 15 publications

References 7 publications

Effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope

Effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope

Non-Uniform Temperature Fields and Effects of Steel Structures: Review and Outlook

Estimation of Pointing Errors of Large Radio Telescopes under Solar Radiation Based on Digital Twin

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