Yuezhao Zhu

Risk assessment of agricultural irrigation water under interval functions

In recent years, water shortages and unreliable water supplies have been considered as major barriers to agricultural irrigation water management in China, which are threatening human health, impairing prospects for agriculture and jeopardizing survival of ecosystems. Therefore, effective and efficient risk assessment of agricultural irrigation water management is desired. In this study, an inexact full-infinite two-stage stochastic programming (IFTSP) method is developed. It incorporates the concepts of interval-parameter programming and full-infinite programming within a two-stage stochastic programming framework. IFTSP can explicitly address uncertainties presented as crisp intervals, probability distributions and functional intervals. The developed model is then applied to Zhangweinan river basin for demonstrating its applicability. Results from the case study indicate that compromise solutions have been obtained. They provide the desired agricultural irrigation water-supply schemes, which are related to a variety of tradeoffs between conflicting economic benefits and associated penalties attributed to the violation of predefined policies. The solutions can be used for generating decision alternatives and thus help decision makers to identify desired agricultural irrigation targets with maximized system benefit and minimized system-failure risk. Decision makers can adjust the existing agricultural irrigation patterns, and coordinate the conflict interactions among economic benefit, system efficiency, and agricultural irrigation under uncertainty.

Thermal Performance of a Single-Pass All-Glass Parabolic Trough Receiver

AbstractA novel single-pass all-glass parabolic trough receiver (SPAG-PTR) was developed and the parabolic trough solar collector with concentration ratio of 7.5 was built to investigate the thermal performance of the SPAG-PTR. The indoor heat loss tests were settled as well as the outdoor experiments in quasi-steady-state and transient-state test conditions. The heat loss per unit absorber area of the SPAG-PTR in the average absorber temperature from 100 to 287°C was within the range of 85–674  W/m2, which represents a better heat loss performance (−15%) upon the Sanle-3 receiver (Nanjing Sanle Electronic Information Industry Group, Nanjing, China). The experimental efficiency in transient state was within the range of 0.53–0.73 with the experimental relative error of approximately 3.6–6.5%. In addition, the experimental efficiency curve in quasi-steady-state was obtained. In quasi-steady-state, the experimental efficiency was approximately 0.65–0.71 when the inlet heat transfer fluid temperature was in ...

An initial investigation of the thermal-fluid characterization of a visualized loop thermosyphon

A initial investigation on the thermal-fluid performance of the visualized glass-water loop thermosyphon (LTS) with an U-turn compensation tube is reported in this article. The U-turn compensation tube may contribute to the unidirectional flow of the working fluid in the LTS. The results show that the favorable working fluid filling ratio is within the range of 43% to 70%. Fast startup of 10~40 s and thermal resistance of 0.625~0.7 °C/W of the LTS at the favorable filling ratio is achieved. The bulk boiling position in the evaporator moves away from the inlet of the evaporator with the increase of the filling ratio. When the value of charge ratio is up to 83%, the oscillation of the working fluid occurs in the loop cycle. The inclination angle within the range of 0~50° has a slight impact on the thermal performance of the LTS.

Operation Characteristics of a High Temperature Special Shaped Heat Pipe Used in Solar Thermochemical Reactors

ABSTRACT Solar energy can be transformed to storable chemical fuels through high temperature thermochemical processes driven by concentrated solar radiation. Solar thermochemical reactors (STRs) are the key equipment to these processes. An STR integrated with heat pipe technology is proposed. The core part of this reactor is a high temperature special shaped heat pipe (HTSSHP), which is composed of a flat disk-shape evaporator and multiple cylindrical condensers. A second generation HTSSHP with sodium as the working fluid was fabricated and tested in this work. The evaporating behaviors of sodium and isothermal characteristics were investigated at various operation conditions. A temperature pulsation phenomenon on heating surface was observed lasting for a short period during its startup when the heat flux beyond 47.2 kW/m2, implying the generation of film boiling. Further, the operation characteristic of HTSSHP was experimentally proven steady under various heat fluxes and inclination angles, and it showed a good ability to spread temperature at the cooling side where the thermochemical processes take place. This work will facilitate the preliminary understanding of the operation characteristics in HTSSHP.