Sürdürülebilir Kalkınma Amaçları
Yayınlar
- Derleme MakaleYalnız künye2023Scopus SJRQ1A review of advances in mechanical behaviors of the underground energy transmission pipeline network under loads
Zheng, Qiang; Xu, Qian; Shu, Zekai; Yang, Di; Chen, Weiwang; Akkurt, Nevzat; Zhang, Hui; Lin, Lin; Zhang, Xinxin; Ding, Yulong
The safety of underground energy transmission pipeline network is threatened by traffic, earthquakes, explosions, and other stresses. To solve the problem of damage to the underground energy transmission pipeline networks by external loads, this study analyzed the mechanical properties of the Pipe-Soil Coupling System (PSCS) under external loads from a mechanical perspective. The pipeline constitutive model, the soil constitutive model, the internal effect of the PSCS, the influence of external stresses on the PSCS, and the dynamic response of the PSCS under various research methodologies were all studied. First, different mechanical features of the pipes and soil were employed to investigate the pipe and soil constitutive models. Second, based on the different force directions within the PSCS, the earth pressure and axial friction of the PSCS were investigated to clarify the interaction between the pipe and soil. For the purpose of to better understand the degradation of the underground pipeline state, the impacts of man-made and natural stresses on the PSCS failure were explored. Finally, the results of the investigation of the dynamic response of the PSCS were examined for their applicability using three research methods: theoretical analysis, numerical simulation, and experimental analysis. It is found that the existing constitutive models of pipeline and soil are lack of basis, which increases the difficulty of the selection of constitutive models in the process of research. In the analysis of load effect, earth pressure plays a dominant role in affecting the local stability of pipeline, but the calculation accuracy of soil pressure needs to be improved. Due to the lack of experimental guidance for complex damage phenomena under external loads, it is impossible to accurately determine the limit state parameters of pipelines under complex damage modes. It is critical to create and refine the theory underpinned by numerous experimental data in order to address the issue of pipeline dynamic response under multi-field coupling, including explosion and earthquake. This work is critical for analyzing existing research findings, identifying future research problems, and enhancing buried pipeline safety management.
AtıfScopus15WoS13OpenAlex14
İncele - MakaleYalnız künye2022Scopus SJRQ1Numerical evaluation of convective heat transfer properties of two-dimensional rotating PCM melt in the unilaterally heated rectangular container
Liu, Dinghai; Xie, Kai; Zhang, Hui; Qiang, Yujie; Yang, Di; Wang, Zhaoxiao; Zhu, Lidong; Akkurt, Nevzat; Du, Yanping; Shen, Meng
This paper carried out numerical investigations on the flow and heat transfer characteristics of a phase change with two-dimensional rotation of the three-dimensional paraffin (RT -27)-filled rectangular encapsulated container (PCM-REC) in space. A three-dimensional transient numerical heat transfer model was established and the enthalpy method was used to simulate the solid-liquid phase transition process and the flow evolution at the PCM interface. In this paper, the solid-liquid interface distribution, temperature distribution and melting time of PCM in PCM-REC heated at a constant temperature on one side were compared when rotated at different angles (0°, arctan (0.4), 2arctan (0.4) and 90°) along the heating direction and vertical heating direction. Results demonstrated that the peak value of maximum natural convection velocity increased from 0.0072 m/s to 0.0184 m/s with increasing radial height when PCM-REC was rotated in vertical heating direction. When PCM-REC was rotated in two dimensions by the same angle, the melting time was fastest when γ was an obtuse angle, and with the increase of the obtuse angle, the melting time shortened from 17 min to 6 min; when γ was an acute angle, the melting time was slowest, and with the decrease of the acute angle, the melting time lengthened from 49 min to 288 min.
AtıfScopus35OpenAlex40İncele - MakaleAçık Erişim2022Scopus SJRQ1Experimental study on heat transfer properties of gravity heat pipes in single/hybrid nanofluids and inclination angles
Wang, Zhaoxiao; Zhang, Hui; Yin, Lei; Yang, Di; Yang, Gang; Akkurt, Nevzat; Liu, Dinghai; Zhu, Lidong; Qiang, Yujie; Yu, Fan
In order to meet the working requirements of heat pipes under complex working conditions and high heat flux density, and propose corresponding thermal management solutions. In this paper, the single and hybrid nanofluids (TiO2-H2O, Al2O3-H2O, Al2O3+TiO2-H2O) with mass fraction of 5% under the gradient of gravity heat pipe at 50°, 60°, 70°, 80°, 90° are studied. The changes in thermal resistance, thermal efficiency and equivalent heat transfer coefficient of water were compared with deionized water. The results are as follows: The overall efficiency of gravity heat pipe ranges from 70% to 85%. Compared with deionized water, the nanofluid can effectively improve the heat transfer. At different inclination angles, the hybrid nanofluid with the same mass fraction shows the reverse trend compared with the single nanofluid by decreasing the thermal resistance of the heat pipe and increasing the heat transfer efficiency. At an inclination angle of 70°, the heat transfer efficiency of the nanofluid Al2O3+TiO2-H2O is 6.8% weaker compared to TiO2-H2O and 4.5% weaker compared to Al2O3-H2O. At a tilt angle of 60°, the heat transfer capacity of Al2O3+TiO2-H2O nanofluid increases by 7.3% compared to TiO2-H2O and by 5.6% compared to Al2O3-H2O.
AtıfScopus47OpenAlex45İncele - MakaleAçık Erişim2022Scopus SJRQ1Experimental study on synergistic enhancement of thermal performance of a closed two-phase thermosyphon by a TiO2nanofluid doped with Al2O3
Xu, Qian; Yang, Gang; Jia, Shuhui; Wang, Zhaoxiao; Akkurt, Nevzat; Zhang, Hui; Zhou, Qiang; Shen, Meng; Yang, Di; Zhu, Lidong
The heat transfer performance of two-phase closed thermosyphon solar collectors (TPCTs) can be improved by adding nanoparticles to the conventional working fluid, but it is necessary to ensure good rheological properties while improving the heat transfer performance. Therefore, spherical (TiO2) nanoparticles with good rheological properties and rod-shaped (Al2O3) nanoparticles with high thermal conductivity were mixed and applied to the TPCT. First, the effects of individual factors such as the concentration of nanoparticles and the operating parameters on the thermal performance of the TPCT were investigated and a regression analysis was performed. Then, the joint effect of inclination angle and filling ratio on the thermal performance of TPCT was further investigated by orthogonal experiment. The results show that doping TiO2 with Al2O3 can further improve the thermal performance of TPCT. For the volume concentration of 0.6% of nanoparticles, filling ratio of 50% and inclination angle of 80°, the best heat transfer performance of TPCT was achieved. Compared with the deionized water (DW), the thermal resistance of the single (TiO2-H2O) and hybrid (Al2O3+TiO2-H2O) nanofluid TPCT is reduced by 10.7% and 13.4%, the thermal efficiency is increased by 11.0% and 13.7%, and the equivalent heat transfer coefficient is increased by 16.2% and 18.7%, respectively.
AtıfScopus38OpenAlex41İncele