Effect of Flow Steering Angle Toward the Hydrokinetic Turbine Performance

The kinetic turbine is one of the solutions for use in low-speed river flows ranging from 0.01–2.8 m/s. This kinetic turbine is used as a conversion equipment to convert the water kinetic energy into an electrical energy. The working principle of a kinetic turbine is utilizing and relies on the water kinetic energy. Water flowing into the turbine area will produce a momentum on the turbine blades. This momentum change would then push the turbine blades and finally spin the turbine runner. The aim of research is thedetermination of the effect of water flow steering angle (a) and water flow rate variation in the kinetic turbine performance. This research uses vertical axis kinetic turbines with eight curve blade attached to the turbine runner. The variables used are two values of water flow steering angle, namely 25°and 35°. The water flow rate variation of 30 m3/h, 35 m3/h, 40 m3/h and 45 m3/h. The method used in this study uses a real experimental method. These two variations would then compare with the result of a hydrokinetic turbine performance done on the previous research.The results show that the water flow steering angle a affected the kinetic turbine performance (power, efficiency and torque). From these several water flow steering angle and water flow rate variations, the turbine performance with a 35° water flow steering angle get the highest performance compared with the use of 25° and 14° water flow steering angle. The greater the flow angle and the greater the water flow rate, the greater the torque, power and efficiency. The highest turbine power produced, P=17.5 W, occurs on the 35° water steering angle, and on a Q=45 m3/h water flow rate and on a 80 rpm turbine rotation. While the highest turbine efficiency, h=27 %, occurred on the Q=30 m3/h water flow rate, on a 60 rpm turbine rotation and on a water flow steering angle a=35°. The highest turbine torque, 3.1 Nm, occurs at Q=45 m3/h water flow rate at a maximum turbine braking and on a water steering angle a=35°

Predicting Ground Water Flow

In this activity students learn how to draw ground water contours and understand how ground water flow may be predicted. As they complete this activity students will be able to draw a ground water contour map, have a basic understanding of how to predict the direction of ground water flow and understand the interrelated nature of ground water and surface water flow. They will also learn the difference between a gaining stream and a losing stream and why it is important to know the difference. Educational levels: High school, Middle school

The Effects of Different Water Flow Rates on the Survival Rate of Blue Crab (Portunus Pelagicus) Zoea IV - Megalopa Stages

Blue crab (Portunus pelagicus) is a potential marine crustacean's commodity. The increase demand both local and International market of the blue crab result in the culture development of this species. The larval stage of blue crab, especially at zoea IV to megalopa, plays an important rule on the successful of the production of marketable size under culture condition.Low survival rate of zoea IV to megalopa stage mostly due to their photo taxis behavior, thus, they are trapped at the water surface. Management of water flow rate on the zoea IV holding tank may be able to reduce their mortality rate and can reach megalopa stage successfully. The water flow rate management would keep the zoea in the suspension as well as improving the water quality, i.e. increases the dissolved oxygen in the water.This investigation was done to find out the effects of different water flow rates on the survival rate of blue crab (Portunus pelagicus) zoea IV stage. The tested animal was blue crab at zoea IV stage which undergoes an investigation up to megalopa stage. An experimental method with a Completely Randomized Design was applied. The 5 (five) treatments of different water flow rates were used, i.e.: A (0,25 l/minute), B (0,5 l/minute), C (0,75 l/minute), D (1,0 l/minute), E (0,0 l/minute). Each treatment was replicated three times.The results shows that different water flow rates gave a highly significant difference (P<0,01) on the survival rate of blue crab zoea IV - megaloga stage. The highest survival rate at the end of the experiment (at megalopa stage) was at treatment C (0,75 l/minute): 30,44

Medical Image Segmentation by Water Flow

We present a new image segmentation technique based on the paradigm of water flow and apply it to medical images. The force field analogy is used to implement the major water flow attributes like water pressure, surface tension and adhesion so that the model achieves topological adaptability and geometrical flexibility. A new snake-like force functional combining edge- and region-based forces is introduced to produce capability for both range and accuracy. The method has been assessed qualitatively and quantitatively, and shows decent detection performance as well as ability to handle noise

Modification of light utilization for skeletal growth by water flow in the scleractinian coral Galaxea fascicularis

In this study, we tested the hypothesis that the importance of water flow for skeletal growth (rate) becomes higher with increasing irradiance levels (i.e. a synergistic effect) and that such effect is mediated by a water flow modulated effect on net photosynthesis. Four series of nine nubbins of G. fascicularis were grown at either high (600 µE m-2 s-1) or intermediate (300 µE m-2 s-1) irradiance in combination with either high (15–25 cm s-1) or low (5–10 cm s-1) flow. Growth was measured as buoyant weight and surface area. Photosynthetic rates were measured at each coral’s specific experimental irradiance and flow speed. Additionally, the instantaneous effect of water flow on net photosynthetic rate was determined in short-term incubations in a respirometric flowcell. A significant interaction was found between irradiance and water flow for the increase in buoyant weight, the increase in surface area, and specific skeletal growth rate, indicating that flow velocity becomes more important for coral growth with increasing irradiance levels. Enhancement of coral growth with increasing water flow can be explained by increased net photosynthetic rates. Additionally, the need for costly photo-protective mechanisms at low flow regimes could explain the differences in growth with flow

Image and Volume Segmentation by Water Flow

A general framework for image segmentation is presented in this paper, based on the paradigm of water flow. The major water flow attributes like water pressure, surface tension and capillary force are defined in the context of force field generation and make the model adaptable to topological and geometrical changes. A flow-stopping image functional combining edge- and region-based forces is introduced to produce capability for both range and accuracy. The method is assessed qualitatively and quantitatively on synthetic and natural images. It is shown that the new approach can segment objects with complex shapes or weak-contrasted boundaries, and has good immunity to noise. The operator is also extended to 3-D, and is successfully applied to medical volume segmentation

An investigation of air and water dual adjustment decoupling control of surface heat exchanger

The terminal equipment of central cooling system accounts for a significant proportion of the total system's energy consumption. Therefore, it is important to reduce the terminal equipment energy consumption in central air conditioning system. In this study, the difference of the effect of the chilled water flow rate and air supply rate on the surface cooler during the heat transfer process is taken into full account. Matlab/Simulink simulation software is used to model and simulate the heat transfer of surface cooler of the main terminal equipment of air conditioning system. Simulation tests and experimental validations are conducted by using variable chilled water flow rate and variable air supply rate control mode separately. The experiment results show that the simulation model can effectively predict the heat transfer performance of heat exchanger. Further, the study introduced a dual feedback control mode, which synchronously regulates the chilled water flow rate and air supply rate. Also, under certain conditions, the complex heat transfer process of the surface cooler can be decoupled, and single variable control pattern is used to separately regulate the chilled water flow rate and air supply rate. This can effectively shorten the system regulation time, reduce overshoot and improve control performance