![Sample our Economics, Finance,Business & Industry journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5931/TOC-Subject-Sample-2021-Economics-Finance-Business-Industry.jpg"})
ABSTRACT
The turbine is a crucial component in harnessing ocean thermal energy (OTE), and the impact of the nozzle on turbine performance is significant. TC-profile nozzles have been proven to operate efficiently in air turbines under high-temperature and high-pressure conditions. However, their performance in ocean thermal energy conversion (OTEC) turbines using organic working fluids (low-temperature and low-pressure) still requires further research. Therefore, we focused on a practical 100 kW OTEC turbine equipped with different types of TC-profile nozzles. Three-dimensional numerical models were established, and the simulation results demonstrated that the turbine efficiency using TC-3A was generally higher than other turbines, reaching an optimal efficiency of 89.4%. The turbine can operate efficiently at deviations from the design point of + 10.27% or −31.39% in mass flow rate, ±3°C in inlet temperature, and + 20% or −11.43% in rotor speed during off-design conditions. The results revealed the adaptability of TC-3A nozzles to the OTEC environment and their excellent off-design performance. The study could provide valuable guidance and references for the application of TC-type nozzles in the field of OTEC turbines.
Nomenclature
| AR | = | Area ratio |
| b4 | = | Rotor outlet blade width, mm |
| C | = | absolute speed, m/s |
| h | = | Enthalpy, J/kg |
| P | = | Power, kW |
| q | = | Mass flow rate, kg/s |
| U | = | Tangential velocity, m/s |
| W | = | Relative velocity, m/s |
| n | = | Rotational speed, rpm |
| Re | = | Reynolds number |
| Z | = | The vane number of the nozzle |
| L | = | Length, mm |
| Subscripts | = | |
| tur | = | Turbine |
| con | = | Condenser |
| eva | = | Evaporator |
| in | = | Inlet |
| out | = | Outlet |
| ww | = | Warm water |
| cw | = | Cool water |
| r | = | Rotor |
| n | = | Nozzle |
| Greek letter | = | |
| α | = | Absolute airflow angle |
| β | = | Relative airflow angle |
| χ | = | Characteristic ratio |
| ρ | = | Airflow density |
| θ | = | Divergence angle |
| η | = | Efficiency |
| Ω | = | Reaction degree |
| Δ | = | Different |
| ξ | = | Loss |
| τ | = | Clogging coefficient |
| φ | = | Nozzle velocity coefficient |
| Acronyms | = | |
| CC | = | Closed Cycle |
| ORC | = | Organic Rankine Cycle |
| OTEC | = | Ocean Thermal Energy Conversion |
| CFD | = | Computational fluid dynamics |
| ORC | = | Oganic Rankine Cycle |
| 1-D | = | One-dimensional |
| 3-D | = | Three-dimensional |
| PR | = | Peng-Robinson |
Acknowledgements
The financial supports by the Hainan Provincial Natural Science Foundation of China (422CXTD509), the Hainan Province Science and Technology Special Fund (ZDYF2021GXJS021) and the National Natural Science Foundations of China (51769006) are gratefully acknowledged.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Additional information
Funding
Notes on contributors
Qingfen Ma
Qingfen Ma is a professor at Hainan University. Her research interest is the research and application of ocean renewable energy and seawater desalination technology.
Jie Huang
Jie Huang is a postgraduate in Hainan University. His research interest is Ocean Thermal Energy Conversion power generation equipment.
Hui Lu
Hui Lu is an professor in the Institute of Environment and Plant Protection, the Chinese Academy of Tropical Agricultural Sciences. His research interest is the research of green technology.
Hongfeng Luo
Hongfeng Luo is a professor at Hainan University. His research interest is environmental materials and green manufacturing.
Jingru Li
Jingru Li is an associate professor at Hainan University. Her research interest is the structural optimization and vibration control.
Zhongye Wu
Zhongye Wu is a lecturer at Hainan University. His research interest is thermal energy engineering and new energy technology.
Xin Feng
Xin Feng is a postgraduate in Hainan University. His research interest is the comprehensive utilization of Ocean Thermal Energy Conversion.