Article
Thermodynamics
Xinxin Liu, Xiaoxiao Xu, Youzhou Jiao, Chao He, Liang Liu, Chaobin Dang
Summary: The study investigates the mixed turbulent convection heat-transfer characteristics of S-CO2 heated in both vertical and horizontal oriented HC-tube, finding that the coupling effects of buoyancy and centrifugal forces mainly affect heat transfer on the inside of a cross-section and the M-type velocity pattern in HC-tube is different from that in straight tube.
APPLIED THERMAL ENGINEERING
(2021)
Review
Thermodynamics
Mei Yang, Guangrong Li, Fan Liao, Jingde Li, Xiang Zhou
Summary: The study investigated the influence of supercritical CO2 on cooling heat transfer and pressure drop in horizontal helically coiled tube with non-circular cross section. It was found that with the increase of polygon edge number, heat transfer and pressure drop increase, but the range of increase gradually decreases; when the polygon edge number reaches a certain extent, pressure drop decreases. Additionally, the increase in pitch P, diameter d, and radius R leads to a decrease in heat transfer, with different effects on pressure drop.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Zhengming Yi, Yong Xu, Xiaolin Chen
Summary: This study investigates the effects of mass flux and heat flux on heat transfer in a vertical serpentine micro-tube, as well as the different influences of buoyancy and centrifugal force in the liquid-like and gas-like regions. The results show that the heat transfer coefficient decreases with increasing heat flux and increases with increasing mass flux. The liquid-like region is more affected by buoyancy, resulting in significant differences between upward and downward flow heat transfer coefficients, while the gas-like region is less affected, with smaller differences between the coefficients. At the turning point of the micro-tube, centrifugal force weakens heat transfer, with a larger effect in the liquid-like region. These findings provide important insights into the effects of buoyancy and centrifugal force on flow and heat transfer in different regions.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Fucheng Chang, He Hu, Yuhao Shang, Yongpeng Hu, Xi Li, Hailin Lei, Huixiong Li
Summary: The study found that under high mass velocity conditions, there is a significant temperature difference between the inner and outer walls of the helical coil, with the difference reaching an extremum near the critical temperature. Increasing the mass velocity reduces wall temperature inhomogeneity, while increasing heat flux density leads to an increase in wall temperature inhomogeneity.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Yong Xu, Zhengming Yi
Summary: The heat transfer of supercritical CO2 in a serpentine micro-tube under different flow directions is numerically studied in this paper, taking into account the combined effect of gravitational buoyancy, centrifugal force and centrifugal buoyancy. The Richardson number is used to reflect the degree of buoyancy under different flow directions.
Article
Thermodynamics
Dongnan Cai, Xiaoxiao Xu, Shijie Zhang, Chao Liu, Chaobin Dang
Summary: The study focuses on the heat transfer deterioration and flow instability of supercritical CO2 in a tube, where experiments show that flow instability occurs in upward flow tubes due to buoyancy effects and changes in heat transfer modes.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Zhiliang Lei, Zewei Bao
Summary: This study experimentally investigated the laminar heat transfer characteristics of RP-3 in the liquid phase and supercritical phase in helical coiled tubes under 5 MPa pressure. The influences of secondary flow and buoyancy on heat transfer were analyzed, and correlations were established.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Xing Zhou, Sixu Yuan, Zhouhang Li
Summary: This study experimentally investigated the effects of buoyancy and centrifugal forces on local heat transfer in a U-bend and its contiguous horizontal straight tubes using supercritical R410A. The results showed that the enhancement effect was the highest at the bend center, with heat transfer coefficients increasing by 88%, 49%, 28%, and 19% on the outside, top, bottom, and inside, respectively. The U-bend also significantly enhanced heat transfer in the straight tubes adjacent to it. The enhancement effect and affected distance increased with heat flux, mass flux, and inlet temperature, but were barely affected by pressure. A new parameter, /r *, was proposed to quantitatively characterize the competition between the buoyancy effect and the decaying centrifugal effect.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Fucheng Chang, Yuhao Shang, Hailin Lei, He Hu, Jiacheng Lou, Yeming Liu, Huixiong Li
Summary: The analysis of flow and heat transfer characteristics of supercritical water (SCW) is complex due to the significant changes in physical properties near the pseudo-critical line and the secondary flow in helically coiled tubes (HCTs). To understand the heat transfer deterioration (HTD) in SCW, numerical simulation was performed to investigate the distribution of wall temperatures and heat transfer coefficients in a vertical HCT. The results showed that wall temperature was highest on the inner side, while the heat transfer coefficients were lowest. The concept of circumferential wall temperature inhomogeneity (CWTI) was used to quantify the differences in local wall temperature, and it was found that CWTI increased with increasing heat flux. Increasing pressure and mass velocity had different effects on HTD, with pressure suppressing HTD while mass velocity weakening the heat transfer.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Xiao-jing Zhu, Rui-zeng Zhang, Xin Du, Xiao Yu, Qing-gang Qiu
Summary: An experimental investigation on heat transfer in vertical upward supercritical CO2 flow was conducted, and correlations and buoyancy parameters were evaluated based on the experimental data. A segmented correlation considering buoyancy was proposed to predict the heat transfer behavior.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Nuclear Science & Technology
Huaishuang Shao, Chao Li, Min Liao, Yibo Wang, Zhiyuan Liang, Qinxin Zhao
Summary: The flow and heat transfer characteristics of supercritical CO2 in a horizontal tube under ocean rolling condition were investigated. It was observed that the rolling motion could mitigate the heat transfer deterioration at the top of the tube. However, the heat transfer deterioration occurred periodically with the rolling motion, leading to temperature and thermal stress fluctuations in the tube wall, which could affect the service life. The impact of rolling motion on heat transfer performance increased at relatively small mass flow rates or large heat fluxes due to the significant density difference and buoyancy. With the increase of inlet temperature and the decrease of buoyancy effect, the influence of rocking motion on heat transfer gradually decreased. The influence of rolling motion on heat transfer should be considered in the design of floating nuclear power plants.
ANNALS OF NUCLEAR ENERGY
(2023)
Article
Thermodynamics
Yong Cao, Xiaoxiao Xu, Dan Li, Chao Liu, Chaobin Dang
Summary: This study investigates the heat transfer characteristics of supercritical CO2 (S-CO2) in a smooth tube and a smooth tube with Helmholtz oscillators. The results show that the heat transfer deterioration of S-CO2 can be significantly inhibited by the Helmholtz oscillator. The pulsating flow generated by the oscillator enhances the disturbance between near-wall fluid and core fluid, resulting in more uniform thermophysical properties of S-CO2 and weaker buoyancy effect.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Alper Gungor, Ataollah Khanlari, Adnan Sozen, Halil Ibrahim Variyenli
Summary: In this study, a conventional shell and helically coiled heat exchanger was modified by integrating discs and rings, aiming to improve its thermal performance. Numerical simulations and experimental tests were conducted, and the modified heat exchanger showed higher heat transfer rate and coefficient compared to the conventional one.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Joo Hyan Park, Jae Eun Cha, Si Woo Lee
Summary: This study focuses on the design and performance evaluation of a 150-kW-class supercritical CO2 centrifugal compressor for a 500-kW power generation system. Experimental tests showed that the compressor achieved a high efficiency of 80% during four repeated tests, confirming its practicality for the supercritical CO2 power generation system. The reliability of the compressor performance was examined and the effects of control valve opening rate and impeller rotational speed on load changing were analyzed.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Jian Chen, Hua Chen, Rui Zhao, Jia-Liang Song, Yong-Le Nian, Wen-Long Cheng
Summary: This study conducted experimental studies in a high p/C spiral tube and compared it with a straight tube. The results showed that the spiral tube can improve heat transfer efficiency and has less impact from buoyancy effect compared to the straight tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Sihui Hong, Chaobin Dang, Eiji Hihara
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2020)
Article
Green & Sustainable Science & Technology
Hao Li, Xiufeng Gong, Wenjie Xu, Minxia Li, Chaobin Dang
Article
Construction & Building Technology
Wei Sheng, Xueli Li, Ruirui Wang, Chaobin Dang, Mengjie Song
ENERGY AND BUILDINGS
(2020)
Article
Thermodynamics
Dongnan Cai, Xiaoxiao Xu, Shijie Zhang, Chao Liu, Chaobin Dang
Summary: The study focuses on the heat transfer deterioration and flow instability of supercritical CO2 in a tube, where experiments show that flow instability occurs in upward flow tubes due to buoyancy effects and changes in heat transfer modes.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Zhihua Zhang, Makoto Ito, Chaobin Dang, Yu Chen, Eiji Hihara
Summary: This study aimed to explore the possibility of commercializing split air conditioners using HFO-1123, requiring the development of technology to suppress its disproportionation reaction. The threshold pressure and flame temperature of the disproportionation reaction were experimentally determined, and the effectiveness of using different inhibitors to suppress the disproportionation reaction was evaluated.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2021)
Article
Thermodynamics
Xinxin Liu, Xiaoxiao Xu, Youzhou Jiao, Chao He, Liang Liu, Chaobin Dang
Summary: The study investigates the mixed turbulent convection heat-transfer characteristics of S-CO2 heated in both vertical and horizontal oriented HC-tube, finding that the coupling effects of buoyancy and centrifugal forces mainly affect heat transfer on the inside of a cross-section and the M-type velocity pattern in HC-tube is different from that in straight tube.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Jiacheng He, Ryusuke Hirata, Eiji Hihara, Chaobin Dang
Summary: The membrane-based desorber offers a promising alternative for miniaturizing the present generator in absorption refrigeration systems by virtue of its large specific interfacial area; the heat and mass transfer characteristics of a desorber consisting of a porous polytetrafluoroethylene hollow fiber membrane were evaluated through experiment and simulation; the results showed an increase in solution flowrates leading to a higher water vapor desorption rate.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Shizuo Saitoh, Tomohiro Higashi, Makoto Ito, Chaobin Dang, Eiji Hihara, Yuji Shitara
Summary: By conducting experiments on the combustion of refrigeration oil, refrigerant, and air mixtures, it was found that the concentration of reaction inhibitors in the refrigeration oil has an effect on combustion suppression. The combustion range became narrower and the maximum pressure decreased as the concentration of the additive increased.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2023)
Article
Thermodynamics
Zhihua Zhang, Makoto Ito, Chaobin Dang, Yu Chen, Eiji Hihara
Summary: HFO-1123 is a promising refrigerant with low global warming potential. The addition of other refrigerants was investigated to suppress the disproportionation reaction of HFO-1123. Experimental results showed that a narrow slit in the center can cool and extinguish the flame ignited at the bottom of the vessel under high-temperature conditions.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2023)
Article
Thermodynamics
Yong Cao, Xiaoxiao Xu, Dan Li, Chao Liu, Chaobin Dang
Summary: This study investigates the heat transfer characteristics of supercritical CO2 (S-CO2) in a smooth tube and a smooth tube with Helmholtz oscillators. The results show that the heat transfer deterioration of S-CO2 can be significantly inhibited by the Helmholtz oscillator. The pulsating flow generated by the oscillator enhances the disturbance between near-wall fluid and core fluid, resulting in more uniform thermophysical properties of S-CO2 and weaker buoyancy effect.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Yingling Li, Minxia Li, Chaobin Dang
Summary: Utilizing the frosting-defrosting process is a simple and novel method for dust removal in heat exchangers. The effect of surface wettability on dust removal characteristics during the frosting cleaning process was studied through experiments on four types of copper surfaces. Results showed that hydrophilic, bare, and sliding surfaces effectively removed dust particles, while super-hydrophobic surfaces wrapped dust particles into the curling frosting layer. The super-hydrophobic surface had the highest dust removal rate and the shortest defrosting time.
APPLIED THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Jiangchuan Yu, Sihui Hong, Sasaki Koudai, Chaobin Dang, Shuangfeng Wang
Summary: This paper introduces a flat plate pulsating heat pipe (ASCPHP) with adaptive structured channels to enhance the thermal performance of PHP systems. Compared to traditional PHP systems, the ASCPHP design achieves a lower evaporation temperature and a more uniform temperature distribution, reducing thermal resistances by up to 37.5%. Experimental results show that the ASCPHP exhibits the quickest start-up response and the lowest start-up temperature, with minimal dependence on gravity.
Article
Thermodynamics
Qifan Wang, Xuetao Liu, Minxia Li, Dandan Su, Chaobin Dang
Summary: This study investigates the replacement of high-GWP refrigerants with non-azeotropic refrigerants and the reduction in refrigerant charge. A numerical simulation of falling-film evaporation of a non-azeotropic refrigerant outside a horizontal tube was conducted, considering various influencing factors on the heat transfer coefficient. The results indicate that spray height, tube diameter, inlet temperature, Reynolds number, and the mass fraction of R32 in the liquid-phase mixture have significant effects on the heat transfer coefficient.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Linlin Wang, Chaobin Dang, Eiji Hihara, Baomin Dai
Summary: The use of minichannel heat exchangers in refrigeration and other industries has been increasing due to their high heat transfer efficiency, lightweight, and low carbon emissions. R1234yf/R32, a zeotropic mixture with low GWP, shows promise as a substitute for R410A in commercial refrigeration. This study investigates the condensation heat and mass transfer characteristics of R1234yf/R32 in minichannel test tubes with an inner diameter of 2 mm. The influencing factors on mass transfer and heat transfer coefficient are discussed, and the effects on heat transfer and mass transfer during condensation are analyzed based on the flow pattern and thermophysical properties.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Sihui Hong, Chengzhi Li, Chaobin Dang, Mengjie Song, Hitoshi Sakamoto
Summary: This study investigates the cooling performance of two heat sinks connected in series or in parallel by adjusting the heat load. The results show that when the heat sinks are connected in parallel, the inlet flowrate is evenly distributed and their heat transfer performance is identical. A sudden change in the heat load of one heat sink does not induce flow instability or heat deterioration in the other heat sink.
APPLIED THERMAL ENGINEERING
(2024)
Review
Thermodynamics
Shuling Guo, Ankuo Zhang
Summary: Low-temperature biopreservation is commonly used for medication storage to prolong their shelf life. However, cryo-injury can occur during cryopreservation, making it crucial to find a way to achieve long-term biopreservation without causing harm. The optimal storage temperature for different biomaterials should be investigated to improve storage efficiency. This review discusses the mechanisms of cryo-injury and biopreservation, as well as the reasons for storing biological tissues at various temperature zones. It provides valuable insights for the development of biostorage technology.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
M. Mohsin Tanveer, Craig R. Bradshaw, Joe Orosz, Greg Kemp
Summary: This study investigates the optimal geometric parameters for a spool compressor using simulation models, and the results indicate that a eccentricity ratio of 0.75 and L/D ratios between 1-1.5 can maximize the volumetric and isentropic efficiencies.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Kongkuai Ying, Zhenhua Jiang, Wenting Wu, Jinjian Chu, Shaoshuai Liu, Yinong Wu
Summary: The Stirling/pulse tube cryocooler (SPC) is a highly efficient and long-lasting cryocooler for space applications. It has the ability to adjust the inter-stage refrigeration capacity dynamically by controlling the Stirling displacer in the first stage. This paper proposes an SPC with a second-stage active phase shifter (APS) that can control the phase difference at the second-stage hot end in real time. The experimental results show that the SPC with the APS can provide refrigeration capacity at different temperatures, with a minimum temperature of 13.5K.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Ligeng Li, Hua Tian, Kai Liu, Yibo Wu, Xuan Wang, Xingyu Liang, Gequn Shu
Summary: This study focuses on improving the performance of carbon dioxide refrigeration systems by introducing a multi-ejector design with three controllable ejectors. Experimental analysis shows that the system's performance can be significantly improved by adopting an optimum pressure control strategy under different operating conditions.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Joseph Al Khoury, Rabih Al Haddad, Ghiwa Shakrina, Christelle Bou Malham, Haytham Sayah, Chakib Bouallou, Maroun Nemer
Summary: This study investigates two implementation methods for calculating refrigerant thermodynamic properties and compares their performance. The results show that the implicit fitting method significantly speeds up simulation time and offers greater flexibility for modeling complex energy systems.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Mariella Mateo-Villanueva, Rodolfo Echarri
Summary: This article details three models of different complexity levels for predicting the cold production of a solar cooling device and compares their advantages and disadvantages. The results show that the transient model underestimates the cold generation, while the equilibrium model and universal model overestimate it. The transient model is a useful tool for analyzing the impact of different variables in a solar adsorption refrigeration system, while the simpler models can be used for preliminary design and feasibility studies.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Amin M. Elsafi, Majid Bahrami
Summary: The novel spherical micro-absorbers offer high sorption capacity and surface-to-volume ratios, solving issues such as solution carryover and corrosion associated with conventional absorbers.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
