scholarly journals Scaling of on-board characteristics of waterjet propulsion based on bench thrust testing data and loop test results

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110490
Author(s):  
Zhongyong Pan ◽  
Yongyan Ni
Keyword(s):  
Measuring Error ◽  
Test Results ◽  
Test Rig ◽  
Thrust Coefficient ◽  
Testing Data ◽  
Thrust Characteristics ◽  
Shaft Power ◽  
Torque Coefficient ◽  
Testing Bench ◽  
Power Curves

The on-board “speed-resistance-power” curves are profiled by a fitted jet thrust deduction factor relation, where the raw data are obtained from both bench thrust testing data and loop test results. Firstly, the thrust characteristics of a waterjet were tested by a thrust testing bench, while the pump performance such as capacity, head and shaft power of the waterjet was measured on a loop test rig. The useful fitted jet thrust deduction factor relation involves three related variables, that is to say, thrust coefficient, torque coefficient, and advance coefficient. Then, the best efficiency propulsion points are indicated by a collapsing technology and the subsequent results that the best efficiency propulsion points are actually existed. Cavitation margins are also noted by the two groups of data obtained by the loop data and the bench data, respectively. The discrepancy of the two margins shows the measuring error of the loop test means. In addition, the non-consistency features of the curves in the cavitation zone indicate the complex cavitation instabilities in the waterjet propulsion. At last, the bench tested thrust results are supplemented and therefore a useful map is completed.

scholarly journals Modelling and Parameters Identification of a Quadrotor Using a Custom Test Rig

2018 ◽  
Vol 9 (2) ◽  
pp. 865
Author(s):  
Mohammad Shafiq Mohammad Ashraf ◽  
Mohamad Shukri Zainal Abidin ◽  
Mohd Saiful Azimi Mahmud ◽  
Muhammad Khairie Idham Abd Rahman ◽  
Zakarya Mohammed Nasser Saleh Motea
Keyword(s):  
Control System ◽  
System Identification ◽  
Feedback Control ◽  
Control Algorithm ◽  
Moment Of Inertia ◽  
Unstable System ◽  
Test Rig ◽  
Thrust Coefficient ◽  
Torque Coefficient ◽  
Rotor Model

<span>Quadrotor by nature is a very unstable system and flying it without any feedback control algorithm is deemed impossible. However, before designing the control system, system identification need to be conducted as the accuracy of the control system depends highly on the accuracy of the model. Therefore, this paper explained the design of the quadrotor model with an “X” configuration using the Euler-Newton model. Two types of test rig were designed to measure the thrust coefficient, torque coefficient and throttle command relation parameter needed in the model. Other parameter such as moment of inertia was also being measured by separating the quad rotor model into several sections: Motors, Electronics Speed Controllers (ESC) and Central Hub. All parameters needed in the designed quad rotor model has been successfully identified by measuring the parameters using the custom-built quad rotor and test rigs. The parameters found in this paper will be used in designing the control system for the quadrotor.</span>

Systematic Experimental Investigation of Dielectric Electroactive Polymers Using a Custom-Built Uniaxial Tensile Test Rig

2015 ◽  
Author(s):  
Micah Hodgins ◽  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Pure Shear ◽  
Tensile Force ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Specimen Preparation ◽  
Testing Device ◽  
Test Results ◽  
Test Rig ◽  
Geometry Test

This work presents the design, fabrication and testing of a comprehensive DEAP test station. The tester is designed to perform tensile tests of planar DEAPs while measuring quantities such as tensile force, stretch, film thickness and voltage/current. The work details the specimen preparation and how the specimen is placed in the clamps. While the assembly process is performed by hand features were built-in to the design of the specimen frame and clamps to enable reliable placement and specimen geometry. Test results of the pure-shear specimen demonstrated good performance of the testing device. Although the electrode surface was rough the thickness stretch was evident during the stretching/actuation of the DEAP actuator.

Prediction of Rotor Burst Using Strain-Based Fracture Criteria to Comply With the Engine Airworthiness Regulation

2020 ◽  
Author(s):  
Huihui Li ◽  
Kaiming Wang ◽  
Chuncheng Zhang ◽  
Weiguo Wang ◽  
Guoguang Chen
Keyword(s):  
Test Data ◽  
Aircraft Engine ◽  
True Stress ◽  
Average Stress ◽  
Civil Aviation ◽  
Test Results ◽  
Fracture Criteria ◽  
Testing Data ◽  
Physical Essence ◽  
Dimensional Growth

Abstract Relative to the rotor overspeed compliance governed by civil aviation airworthiness regulation, nowadays Area-Average Stress method is commonly used approach. However, in order to effectively apply the Area-Average Stress method in analyzing burst speed, large amount of testing data is needed to define an important element of this method: a correction factor. This prerequisite hinders the use of this method for many companies which have limited test data. Meanwhile, analysis of rotor burst speed based on Strain-based Fracture Criteria using true stress-strain curves and burst tests has been done on the LPT rotor, and a work procedure obtaining the most critical burst speed for certification is proposed. The analysis results, which had a good correlation with test results, showed that Strain-based Fracture Criteria can accurately predict the burst speed considering the most adverse combination of dimensional tolerances, temperature, and material properties, and rotor dimensional growth under the overspeed condition. Both are required by the aircraft engine airworthiness overspeed regulation. Compared to the Area-Average Stress method, Strain-based Fracture Criteria reflects the physical essence of the rotor burst more realistically and can be simply verified without requiring too much test data, therefore it has a good application prospect in the aircraft engine airworthiness.

scholarly journals Thermal Comfort Evaluation of Rooms Installed with STPV Windows

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 808 ◽  
Author(s):  
Hao Tian ◽  
Wei Zhang ◽  
Lingzhi Xie ◽  
Zhichun Ni ◽  
Qingzhu Wei ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Indoor Environment ◽  
Thermal Sensation ◽  
Test Results ◽  
Test Unit ◽  
Maximum Difference ◽  
Test Rig ◽  
Comfort Evaluation ◽  
The Difference ◽  
Better Than

Thermal comfort is an important aspect to take into consideration for the indoor environment of a building integrated with a semi-transparent Photovoltaics (STPV) system. The thermal comfort of units with photovoltaic windows and that of conventional windows, which is an ordinary without PV, were evaluated via on-site tests and questionnaires. Using the thermal comfort investigation of the test rig, the maximum difference in air temperature was found to be around 5 °C between test unit and comparison unit. The predicted mean vote (PMV)–predicted percentage dissatisfied (PPD) value of the test unit was better than that of the comparison unit. It was observed that on sunny days, the PMV value ranged from 0.2 (nature) to 1.3 (slightly warm) in the test unit, and that of the comparison unit was 0.7 (slightly warm) to 2.0 (warm), thereby providing better thermal comfort, especially during mornings. The maximum difference in PPD values was found to reach 27% between the two units at noon. On cloudy days, the difference was negligible, and the thermal sensation between the foot and the head were almost the same. Fifty respondents were asked to complete a carefully designed questionnaire. The thermal sensation of the test unit was better than that of comparison unit, which corresponded with the test results. Thermal, lighting, acoustic, and other environment comfort scores were combined, and the acceptance of the test unit with the STPV windows was found to be 73.8%. The thermal sensation difference between men and women was around 5%. Thus, during summer, STPV windows can improve the thermal comfort and potentially reduce the air-conditioning load.

An Investigation of the Flow Characteristics and of Losses in Radial Nozzle Cascades

1984 ◽  
Vol 106 (2) ◽  
pp. 502-509 ◽  
Author(s):  
S. G. R. Hashemi ◽  
R. J. Lemak ◽  
J. A. Owczarek
Keyword(s):  
Flow Characteristics ◽  
Leading Edge ◽  
Injection Technique ◽  
Test Results ◽  
Test Rig ◽  
Water Test ◽  
Edge Vortex ◽  
Loss Coefficients ◽  
Radial Nozzle ◽  
Nozzle Blade

A study was made of the flow in radial nozzle cascades using an air test rig and a water test rig. In the air test rig, three cobra probes were used in circumferential and spanwise traverses to determine the total pressure variations in the flow field at three radii downstream of the nozzles at which static pressure was also measured. The tests were made on two sets of nozzle blades having heights of 0.148 in. (0.376 cm) and 0.200 in. (0.508 cm), at trailing edge angles (measured from circumferential direction) of 15, 20, and 25 deg, and at two flow Mach numbers of approximately 0.2 and 0.35. The test results presented in this paper, in the form of loss coefficients and flow angles, were flow-weighted and averaged. Flow visualization in the air test rig was made on the walls bounding the nozzle blades using the graphite power-oil mixture technique. Additional tests were made on the water test rig using dye injection technique. Photographs were obtained showing clearly formation of secondary flow around each nozzle blade in the form of the leading edge vortex. The test results confirm the existence of the leading edge vortices reported peviously, and extend their study to the radial nozzle cascades.

CFD Assessment of Rotordynamic Coefficients in Labyrinth Seals

2014 ◽  
Author(s):  
Sai S. Sreedharan ◽  
Giuseppe Vannini ◽  
Hiteshkumar Mistry
Keyword(s):  
High Speed ◽  
Test Results ◽  
Active Magnetic Bearings ◽  
Test Rig ◽  
Labyrinth Seals ◽  
Cfd Simulations ◽  
Flow Solver ◽  
Rotordynamic Coefficients ◽  
Pressure Test ◽  
Dynamic Seal

Seals used in high speed centrifugal compressors are prone to generate rotordynamic (RD) instabilities. To further understand their influence, a CFD based approach is developed. The objective of the current study is to numerically investigate and characterize the RD coefficients, representative of the dynamic seal forces. Experiments were carried out at high pressure test rig (up to 200 bar seal inlet pressure) which runs at 10000 RPM and has a high pre-swirl (about 0.9) along the same direction of rotor rotation. The rotor shaft in the experiment was instrumented with active magnetic bearings (AMBs) to linearly excite the rotor at three different frequencies: 28 Hz, 70 Hz and 126 Hz. Each frequency is characterized by amplitude of vibration and a phase. CFD simulations were carried out using commercial flow solver, using similar boundary conditions as that of experiments. The paper describes details of CFD model and its comparison against experiments. Numerical results show reasonable agreement of RD coefficients with test results. This job has to be considered as a first approach to CFD methodology applied to annular seals for the authors.

Experimental Evaluation of Evaporative Cooler Using Agro Materials

2015 ◽  
Vol 23 (04) ◽  
pp. 1550028 ◽  
Author(s):  
R. Ramkumar ◽  
M. Kesavan ◽  
A. Ragupathy
Keyword(s):  
Ambient Condition ◽  
Experimental Results ◽  
Test Results ◽  
Test Rig ◽  
Air Velocity ◽  
Different Types ◽  
Saturation Efficiency ◽  
Evaporative Cooler ◽  
Luffa Sponge ◽  
Efficiency Improve

The purpose of the study is to investigate the direct evaporate cooler in hot and humid regions with two different types of agro-based materials. In our experimental study, the locally available agro materials luffa (Sponge Gourd), zizanioides (Vetiver) were used with various thickness and the experimental results were compared with mathematical values. The operating parameters of pad thickness, air velocity, were changed and the performance of the cooler was analyzed. A test rig was designed and fabricated to collect experimental data. The performance of the evaporative cooler was evaluated based on the ambient condition. The analysis of the data indicated that cooling saturation efficiency improve with decrease of air velocity and higher pad thickness. It was shown that zizanioides-based pad with 160[Formula: see text]mm thickness has the higher performance (88%) at 4.5[Formula: see text]m/s air velocity in comparison with luffa pad materials. The experimental results of outlet air temperature and number of transfer units (NTU) were compared with mathematical model. The test results were within the limit of 15% and 10% to mathematical values.

A General Model for Two-Point Contact Dry-Friction Whip and Whirl: Further Advancements and Experimental Test Results

2015 ◽  
Author(s):  
Jason C. Wilkes ◽  
Tim Allison
Keyword(s):  
Experimental Test ◽  
General Model ◽  
Dry Friction ◽  
Point Contact ◽  
Current Work ◽  
Test Results ◽  
Air Bearings ◽  
Test Rig ◽  
Single Location ◽  
Arbitrary Phase

Numerous papers have investigated the behavior of dry-friction whip and whirl; most of them consider contact between a rotor and stator at a single location. For rotors running on multiple magnetic bearings, air bearings, or bushings, equipment failure may result in rub at more than one location. For these cases, it is important to have an analytical model that characterizes possible regions of two-point contact dry-friction whip and whirl. The current work presents a general model to predict possible whirl regions for multi-contact dry-friction whip and whirl, allowing for an arbitrary phase between contact locations. In theory this method can be applied to more than two contact locations; however, a two-point contact example case is developed and compared to results from an experimental test rig developed to demonstrate multi-contact dry-friction whip and whirl in the current work.

Introduction and Commissioning of the New Darmstadt Transonic Compressor Test Facility

2019 ◽  
Author(s):  
Christian Kunkel ◽  
Jan Werner ◽  
Daniel Franke ◽  
Heinz-Peter Schiffer ◽  
Fabian Wartzek ◽  
...  
Keyword(s):  
Control Systems ◽  
Gas Turbines ◽  
State Of The Art ◽  
Test Facility ◽  
Test Results ◽  
Test Rig ◽  
Vast Number ◽  
Transonic Compressor ◽  
Profound Knowledge ◽  
And Control

Abstract With the well-known Transonic Compressor Darmstadt (TCD) in operation since 1994, profound knowledge in designing and operating a sophisticated test-rig is available at the Institute of Gas Turbines and Aerospace Propulsion of TU Darmstadt. During this period, TCD has been subject to a vast number of redesigns within different measurement campaigns (see [1], [2], [3], [4], [5], [6], [7], [8]). To expand the capabilities and ensure a sustainable process of compressor research, a new test facility was designed and built by the institute. The new test rig Transonic Compressor Darmstadt 2 (TCD2) features increased power for higher pressure ratios and higher mass-flow, a state of the art control system, increased flexibility towards different compressor geometries and modern data acquisition hardware and software. Following the successful commissioning of the test-rig in March 2018, a first measurement campaign has been conducted. Early test results regarding aerodynamic performance and aeroelastic effects of the test compressor are presented together with a detailed overview of test-rig infrastructure and control systems as well as the test compressor and the measurement hardware.

Design and Numeric Simulation of a Thermoacoustic Bi-Directional Turbine Test Rig

2019 ◽  
Author(s):  
Dongdong Liu ◽  
Yanyan Chen ◽  
Wei Dai ◽  
Ercang Luo
Keyword(s):  
Acoustic Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Typical Result ◽  
Test Rig ◽  
Impulse Turbine ◽  
Power Generators ◽  
Numeric Simulation ◽  
Shaft Power ◽  
New Type

Abstract As a new type of acoustic-electric conversion method, bi-directional impulse turbine provides great potential for developing large scale and economic thermoacoustic power generators. A test rig for turbine tests in acoustic fields, which are provided through two reciprocating pistons, has been introduced. A three-dimensional numerical model has been used to simulate the whole system. The fundamental characteristics of the turbine in oscillating flow are analyzed. Impact of acoustic field features on the turbine performance has been studied. The results show that the performance is sensitive to the acoustic field. For the test rig, a typical result is that with a shaft power of 187 W, the turbine can reach an efficiency around 32%.

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