scholarly journals Estimating the Evaporation from Irrigation Canals in Northwestern China Using the Double-Deck Surface Air Layer Model

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Suhua Liu ◽  
Weizhen Wang ◽  
Makito Mori ◽  
Tetsuo Kobayashi
Keyword(s):  
Heat Balance ◽  
Field Experiments ◽  
Surface Wind ◽  
Balance Method ◽  
Northwestern China ◽  
Heihe River ◽  
Irrigation Canals ◽  
Layer Model ◽  
The Heat Balance ◽  
Surface Air Layer

The evaporation from irrigation canals was estimated by the aerodynamic method based on the double-deck surface air layer model (called “DSAL model” for short hereafter). The DSAL model describes the surface air layer over a canal as a composite air layer with two sublayers, the lower sublayer and the upper sublayer. The lower sublayer is a few tens of centimeters thick and formed by the flowing water, in which there is no advection; the upper sublayer is over the lower sublayer and formed by the surface wind. The results were compared to those obtained by the heat balance method; field experiments were conducted in the middle reaches of the Heihe River in northwestern China. Results showed that cumulative evaporation instances estimated by the DSAL model were equal in order of magnitude to those by the heat balance method on observed days during the daytime (0700~1900 BST). We infer from these experimental results that the evaporation loss in transport in this region is of the order of one percent at most.

Thermodynamic Evaluation of Gas Turbine Cogeneration Cycles: Part II—Complex Cycle Analysis

1987 ◽  
Vol 109 (1) ◽  
pp. 8-15 ◽  
Author(s):  
I. G. Rice
Keyword(s):  
Gas Turbine ◽  
Heat Balance ◽  
Steam Injection ◽  
Balance Method ◽  
Visual Perspective ◽  
Thermodynamic Evaluation ◽  
The Future ◽  
Steam Cooling ◽  
The Heat Balance ◽  
Regenerative Cycle

Complex open gas turbine cycles are analyzed by applying the heat balance method presented in Part I of this paper. Reheating, intercooling, regeneration, steam injection, and steam cooling are evaluated graphically to give a visual perspective of what takes place in terms of the overall heat balance when such complexities are introduced to the cycle. An example of a viable, new, intercooled regenerative cycle is given. A second example of a prototype reheat gas turbine is also included. The overall approach using the heat balance method can be applied to various cogeneration configurations when considering the more complex cycles of the future.

scholarly journals Estimating Evaporation from Irrigation Canals in the Midstream Areas of the Heihe River Basin by a Double-Deck Surface Air Layer (DSAL) Model

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1788
Author(s):  
Weizhen Wang ◽  
Feinan Xu ◽  
Suhua Liu ◽  
Long Wei ◽  
Jiaojiao Feng ◽  
...  
Keyword(s):  
River Basin ◽  
Irrigation Water ◽  
Heihe River Basin ◽  
Heihe River ◽  
Irrigation Canals ◽  
Running Water ◽  
Evaporation Loss ◽  
Surface Air Layer ◽  
The Heihe River Basin

Accurate quantification of evaporation loss from irrigation canals at an irrigation district scale is very useful for developing efficient irrigation strategies, particularly in water-deficient regions. The double-deck surface air layer (DSAL) model, a new aerodynamic method proposed by Kobayashi et al. (2013), is used for estimating the evaporation loss from a running water surface in irrigation canals. In this study, based on the long-term meteorological measurements made at automatic weather stations in 2013 and the field experiment conducted at - midstream areas of the Heihe River Basin (HRB), northwestern China, the DSAL model was applied to estimate the long-term evaporation loss from irrigation canals, which was the remarkable highlight of the study. The results showed that the rate of evaporation from irrigation canals exhibited a concave-up trend for the period from June to September, with higher values in June and September (20 to 50 mm day−1) and lower values in July and August (around 10 mm day−1). During the four months, for the Yingke and Daman irrigation districts in the Zhangye Oasis, the total water losses from irrigation canals due to evaporation were approximately 23.9 × 105 m3 and 36.6 × 105 m3, or 3.2% and 4.8% of the total amount of irrigation water, respectively. Results of the study are not only important for improving the irrigation water use efficiency, but also are beneficial to develop sustainable water resource management in the midstream areas of the HRB.

Sap flow by the heat balance method applied to small size Salix trees in a short-rotation forest

1995 ◽  
Vol 8 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Anders Lindroth ◽  
Jan Cermak ◽  
Jiri Kucera ◽  
Emil Cienciala ◽  
Henrik Eckersten
Keyword(s):  
Heat Balance ◽  
Sap Flow ◽  
Balance Method ◽  
Rotation Forest ◽  
Short Rotation ◽  
Short Rotation Forest ◽  
The Heat Balance
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