scholarly journals Analisa pengaruh sudut sudu terhadap kinerja turbin kinetik poros horisontal dan vertikal

2018 ◽  
Vol 1 (1) ◽  
pp. 51
Author(s):  
Yasinta Sindy Pramesti
Keyword(s):  
Flow Rate ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Fluid Velocity ◽  
Maximum Output Power ◽  
Rate Variation ◽  
Maximum Output ◽  
Direction Angle ◽  
Turbine Performance ◽  
Higher Power

Kinetic turbine is a type of power plant that utilizes the energy stored in the water flow ie potential energy and kinetic energy that will be converted into mechanical energy. One of the factors that affect turbine performance is angle angle. The research methodology in this kinetic turbine utilizes the fluid velocity (water) that moves with. The variation of the flow steering angle with the angle to be studied uses an angle of 5 ° 10 °, 15 ° and flow rate variation 50, 70 and 90 m³ / hr. In addition, this kinetic turbine uses vertical and horizontal axis variations. Based on the result of the research, it can be concluded that the maximum output power produced by turbine at 1.53 Watt occurred at 90 m3 / hr discharge with flowing direction angle of 15⁰. The highest efficiency of 18% occurs at a flow rate of 50 m3 / h with a flow direction angle of 15⁰. Horizontal axle turbines have slightly higher power and efficiency values when compared to a vertical axle turbine.

Effects of Disturbance of Current Field on Power Characteristics of a Floating Type Pitch-Controlled VAMT in a Real Sea

2016 ◽  
Author(s):  
Tomoki Ikoma ◽  
Koichi Masuda ◽  
Hiroaki Eto ◽  
Chang-Kyu Rheem ◽  
Osamu Enomoto
Keyword(s):  
Fluid Velocity ◽  
Vertical Axis ◽  
Ocean Waves ◽  
Floating Body ◽  
Maximum Output ◽  
Power Characteristics ◽  
Turbine Performance ◽  
Velocity Changes ◽  
Floating Type ◽  
Japanese Islands

While a type of marine turbine for tidal current generation can be chosen from several types, a vertical axis marine turbine (VAMT) should be better in Japan because sea areas around Japanese islands where current velocity is sufficient are limited. This study conducted a sea test of a VAMT of a floating type installed with six straight pitch-controllable blades. The cycloidal mechanism was adapted for the pitch control. The purpose of the study is to understand effects of ocean waves and motion of a floating body on turbine performance and behaviours of the VAMT in unideal current conditions. Besides, the data taken should be effective to consider that effects in order to design VAMTs. The setup with the setting angle of −30 degrees suggested highest performance from the sea tests, then 15% in maximum turbine power and maximum output was 40W. Ocean waves strongly affected on the turbine performance because fluid velocity changes due to ocean waves and it was unable to neglect the variation of the velocity in spite of small. The characteristics of the turbine sensitively varied because of ocean waves. The results suggested that during accelerating and decelerating incoming fluid speed, characteristics of the turbine were different in each case.

scholarly journals High-Power Eu-Doped GaN Red LED Based on a Multilayer Structure Grown at Lower Temperatures by Organometallic Vapor Phase Epitaxy

MRS Advances ◽  
2017 ◽  
Vol 2 (3) ◽  
pp. 159-164 ◽  
Author(s):  
W. Zhu ◽  
B. Mitchell ◽  
D. Timmerman ◽  
A. Koizumi ◽  
T. Gregorkiewicz ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Output Power ◽  
Multilayer Structure ◽  
Maximum Output Power ◽  
Device Performance ◽  
Maximum Output ◽  
Organometallic Vapor Phase Epitaxy ◽  
Growth Structure ◽  
Red Led ◽  
Higher Power

ABSTRACTA modification of the growth structure of Eu-doped GaN (GaN:Eu) from a monolayer to a multilayer structure (MLS) consisting of alternating GaN and GaN:Eu, was shown to enhance the emission properties. Similarly, lowering the growth temperature of the GaN:Eu to 960°C nearly doubled the photoluminescence emission intensity, and also enhanced device performance. Hence, to design a higher power GaN:Eu red LED, a multilayer structure consisting of 40 pairs of alternating GaN and GaN:Eu was grown at 960°C. This combination resulted in the fabrication of an LED with a maximum output power of 110 μW, which is 5.8 times more output power per GaN:Eu layer thickness as compared to the best previously reported device. Moreover, it was found that the MLS sample grown at 960°C maintained a high crystal quality with low surface roughness, which enabled an increase in the number of pairs from 40 pairs to 100 pairs. An MLS-LED consisting of 100 pairs of alternating GaN/GaN:Eu layers was successfully fabricated, and had a maximum output power of 375 μW with an external quantum efficiency of 4.6%. These are the highest values reported for this system.

scholarly journals EFFECT OF FLOW STEERING ANGLE TOWARD THE HYDROKINETIC TURBINE PERFORMANCE

2019 ◽  
Vol 3 ◽  
pp. 20-31
Author(s):  
Rudy Soenoko ◽  
Hastono Wijaya
Keyword(s):  
Kinetic Energy ◽  
Water Flow ◽  
Flow Rate ◽  
Turbine Blades ◽  
Water Flow Rate ◽  
Rate Variation ◽  
Steering Angle ◽  
Turbine Performance ◽  
Hydrokinetic Turbine ◽  
Turbine Runner

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°.

scholarly journals Flow Stability in a Miniature Centrifugal Pump under the Periodic Pulse Flow

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8338
Author(s):  
Kunhang Li ◽  
Wenqian Xu ◽  
Hua-Shu Dou
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Flow Behavior ◽  
Mechanical Energy ◽  
Flow Stability ◽  
Rate Variation ◽  
Suction Surface ◽  
Pulse Flow ◽  
Periodic Pulse ◽  
Energy Gradient

The flow behavior inside a miniature centrifugal pump, under a periodic pulse flow rate, was studied by means of numerical simulation. For a given incoming periodic pulse flow with a sine wave, the performance of the centrifugal pump was investigated in the section with increasing flow and the section with decreasing flow, and the special points of the flow rate and the periodic flow were identified. Further, the energy gradient method and the Q-criterion were adopted to analyze the internal vertical structure and flow stability. It was found that the regions with large variations in velocity and total pressure were mainly located at the leading edge of the suction surface and the middle area of the pressure surface of the blades. Irregular pressure fluctuation frequency under the periodic pulse flow was shown; this was mainly concentrated in the low-frequency zones close to the impeller’s rotational frequency. In addition, for the same flow rate in the periodic pulse flow, the pressure frequency fluctuation for the increasing flow rate section was higher than that observed for the decreasing flow rate section. It was found that the most unstable sections appeared in the first half-period of the flow rate variation (large flow rate), according to the distributions of the Q criteria of the vortex and the energy gradient function K. In this section, motions of strong vortices led to large gradients of the mechanical energy.

scholarly journals Fabrication and Evaluation of a MEMS Piezoelectric Bimorph Generator for Vibration Energy Harvesting

2010 ◽  
Vol 26 (4) ◽  
pp. 493-499 ◽  
Author(s):  
B. S. Lee ◽  
S. C. Lin ◽  
W. J. Wu
Keyword(s):  
Mechanical Energy ◽  
Maximum Output Power ◽  
Electrical Energy ◽  
Open Circuit ◽  
Maximum Output ◽  
Resistive Load ◽  
Piezoelectric Bimorph ◽  
Vibration Energy Harvesting ◽  
Parallel Polarization ◽  
Piezoelectric Layers

ABSTRACTWe present the development of a MEMS piezoelectric bimorph generator, a cantilever type bimorph which was formed by laminating two PZT piezoelectric layers. Our bimorph generator can scavenge mechanical energy from ambient vibrations and transform it into useful electrical energy. Two poling configurations of the PZT piezoelectric layers of our bimorph MEMS generator were fabricated and tested. A tip proof mass used for adjusting the resonance frequency was also demonstrated. Experimental results confirm that our device possessed a maximum open-circuit output voltage of 1.91VP-P and a 3.42VP-P for a parallel polarization device and a serial polarization device, respectively with a 2g externally applied vibration. At an optimal resistive load, the maximum output power was 1.548μ–W and 1.778μ–W for a parallel polarization device and a serial polarization device, respectively.

Enhanced Thermoelectric Properties of the Zn1-xCdxSb Prepared by Solid State Microwave Synthesis

2021 ◽  
Vol 1039 ◽  
pp. 255-259
Author(s):  
Arej Kadhim
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Output Power ◽  
Power Factor ◽  
Microwave Synthesis ◽  
Maximum Output Power ◽  
Thermal Conditions ◽  
Maximum Output ◽  
Higher Power

This paper displays the fabrication of a thermoelectric (TE) generation module using n-ZnSb and p-Zn0.25Cd0.75Sb bulk TE materials. TE properties of the Zn1-xCdxSb bulks with x= 0, 0.5 and 0.75, in terms of the electrical conductivity () and Seebeck coefficient (S) were measured in the range of 300-500K. The higher power factor (S2σ) values for n-ZnSb and p-Zn0.25Cd0.75Sb bulks were obtained about 2.410-4mW/mK2 at 303K and 1.1810-5 mW/mK2 at 468K, respectively. By variation of the thermal conditions, the maximum output power (Pmax) with two p-n couples generator module was 1.3810-5 mW at hot side temperature of 355K and temperature difference () of 40K. The internal (Rin = 0.17 m) and contact resistances (Rc = 0.67 m) between legs and electrodes were discussed below.

scholarly journals Pengaruh Sudut Pengarah Aliran Pada Turbin Air Crossflow Tingkat Dua Terhadap Putaran dan Daya

2018 ◽  
Vol 3 (1) ◽  
pp. 35 ◽  
Author(s):  
Satria Candra Laksmana ◽  
A'rasy Fahruddin ◽  
Ali Akbar
Keyword(s):  
Water Flow ◽  
Large Scale ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Water Discharge ◽  
Turbine Blades ◽  
Cross Flow ◽  
Small Scale ◽  
Direction Angle ◽  
Study Planning

The potential of hydro energy is very large both for large scale and for small scale. Until now, the need for energy continues to increase, so that energy is a very important element in the development of a country or a region. Cross-flow turbines are one type of turbine that is often used for PLTMH. In this study planning a cross-flow water turbine applied to the height and amount of water per second in the irrigation channel water flow, this water flow will rotate the turbine shaft to produce mechanical energy. With variations in the direction of the turbine flow direction, namely 30o, 35o, and 40o, and the same variation of water discharge 10,5 L / s, 21 L / s and 31,5 L / s to determine the effect on the rotation and the power produced. In this study with 12 turbine blades, 30o blade angle, 40o flow direction angle, and 31.5 L / s water discharge obtained the highest first stage turbine rotation value is 478 rpm. Whereas at the flow direction angle of 30o with the same water discharge which is 31.5 L / s so that the first stage of the turbine is obtained is 296 rpm.

scholarly journals Prediction of Flow and Temperature Distributions in a High Flux Research Reactor Using the Porous Media Approach

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Shanfang Huang ◽  
Daxin Gong ◽  
Chao Li ◽  
Xiaoyu Guo ◽  
Guanbo Wang ◽  
...  
Keyword(s):  
Porous Media ◽  
Flow Rate ◽  
Research Reactor ◽  
Flow Direction ◽  
Coolant Temperature ◽  
Rate Variation ◽  
High Flux ◽  
Fuel Temperature ◽  
The Core ◽  
Porous Media Model

High thermal neutron fluxes are needed in some research reactors and for irradiation tests of materials. A High Flux Research Reactor (HFRR) with an inverse flux trap-converter target structure is being developed by the Reactor Engineering Analysis Lab (REAL) at Tsinghua University. This paper studies the safety of the HFRR core by full core flow and temperature calculations using the porous media approach. The thermal nonequilibrium model is used in the porous media energy equation to calculate coolant and fuel assembly temperatures separately. The calculation results show that the coolant temperature keeps increasing along the flow direction, while the fuel temperature increases first and decreases afterwards. As long as the inlet coolant mass flow rate is greater than 450 kg/s, the peak cladding temperatures in the fuel assemblies are lower than the local saturation temperatures and no boiling exists. The flow distribution in the core is homogeneous with a small flow rate variation less than 5% for different assemblies. A large recirculation zone is observed in the outlet region. Moreover, the porous media model is compared with the exact model and found to be much more efficient than a detailed simulation of all the core components.

Characterization of microwave-sintered ceramic composites

1993 ◽  
Vol 51 ◽  
pp. 1136-1137
Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek
Keyword(s):  
Matrix Material ◽  
Maximum Output Power ◽  
Ceramic Matrix Composite ◽  
Ceramic Composites ◽  
Processing Technique ◽  
Structure Characterization ◽  
Alumina Powder ◽  
Maximum Output ◽  
Sintered Ceramic

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.

scholarly journals Performance Characteristics in Runner of an Impulse Water Turbine with Splitter Blade

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 303
Author(s):  
Lingdi Tang ◽  
Shouqi Yuan ◽  
Yue Tang ◽  
Zhijun Gao
Keyword(s):  
Energy Conversion ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Experimental Tests ◽  
High Energy ◽  
Negative Energy ◽  
Water Turbine ◽  
Conversion Performance ◽  
Water Turbines ◽  
Current Energy

The impulse water turbine is a promising energy conversion device that can be used as mechanical power or a micro hydro generator, and its application can effectively ease the current energy crisis. This paper aims to clarify the mechanism of liquid acting on runner blades, the hydraulic performance, and energy conversion characteristics in the runner domain of an impulse water turbine with a splitter blade by using experimental tests and numerical simulations. The runner was divided into seven areas along the flow direction, and the power variation in the runner domain was analyzed to reflect its energy conversion characteristics. The obtained results indicate that the critical area of the runner for doing the work is in the front half of the blades, while the rear area of the blades does relatively little work and even consumes the mechanical energy of the runner to produce negative work. The high energy area is concentrated in the flow passage facing the nozzle. The energy is gradually evenly distributed from the runner inlet to the runner outlet, and the negative energy caused by flow separation with high probability is gradually reduced. The clarification of the energy conversion performance is of great significance to improve the design of impulse water turbines.

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