Actual Field Test Research Articles

Measurement Uncertainties Encountered During Gas Turbine Driven Compressor Field Testing

Field testing of gas turbine compressor packages requires the accurate determination of efficiency, capacity, head, power and fuel flow in sometimes less than ideal working environments. Nonetheless, field test results have significant implication for the compressor and gas turbine manufacturers and their customers. Economic considerations demand that the performance and efficiency of an installation are verified to assure a project?s return on investment. Thus, for the compressor and gas turbine manufacturers, as well as for the end-user, an accurate determination of the field performance is of vital interest. This paper describes an analytic method to predict the measurement uncertainty and, thus, the accuracy, of field test results for gas turbine driven compressors. Namely, a method is presented which can be employed to verify the validity of field test performance results. The equations governing the compressor and gas turbine performance uncertainties are rigorously derived and results are numerically compared to actual field test data. Typical field test measurement uncertainties are presented for different sets of instrumentation. Test parameters that correlate to the most significant influence on the performance uncertainties are identified and suggestions are provided on how to minimize their measurement errors. The effect of different equations of state on the calculated performance is also discussed. Results show that compressor efficiency uncertainties can be unacceptably high when some basic rules for accurate testing are violated. However, by following some simple measurement rules and maintaining commonality of the gas equations of state, the overall compressor package performance measurement uncertainty can be limited and meaningful results can be achieved.

An Explosive Subsoiler for the Improvement of Meadow Soil, Part 3: Field Experiments

An explosive subsoiler was envisaged for the achievement of greater soil rupture volume and longer sustainability of drainage to improve meadow soil. A prototype explosive subsoiler was designed and built in Japan and sent to China, and actual field tests were conducted in a meadow soil field. This paper details the performance of the explosive subsoiler in the meadow soil.The results showed that when the soil penetration resistance was less than 3·0 MPa, and gas of 10 g/s was injected, a pressure of about 5 kPa was produced at the nozzle port. A base draught of about 20 kN, which was measured when no gas was injected, was reduced to 15 kN. The trace of the subsoiler remained in the soil horizon, and a cavity was formed on the trace of the subsoiler chisel. When the soil penetration resistance was more than 3·0 MPa, the draught reduction could not be obtained even with the pressure produced on the nozzle port. There was a chisel trace in the soil horizon, but there was no cavity formation by the injected gas. The draught of the mouldboard plough body which tilled the Ap horizon was about 10 kN with a working depth of 200 mm. The mean base draught of the subsoiler body, which broke the A and Cg1 horizons, was about 10 kN at 478 mm depth from the soil surface, about 20 kN at 539 mm depth and about 30 kN at the 600 mm depth.

EyeTap technology for wireless electronic news gathering

The results of actual field tests of a new class of Personal Imaging systems, the Electronic News Gathering WearComp (ENGwear), are presented. These incorporate EyeTap Technology to cause the eye itself to function as if it were a camera, and to allow the eye to be wirelessly tapped out of and tapped into, capturing exactly what the user is viewing. This brings the point of view of the camera to the same point as the user's eye, and also allows the user to allow others to wirelessly modify his/her perception of visual reality. Images thus captured are simultaneously sent and received live to and from the internet using IP-over-wireless technology. This novel application of wireless technology empowers reporters: ENGwear systems allow for a great degree of mobility, and are constantly operational and recording to a circular buffer allowing the reporter to never 'miss a shot'.

RFLP markers and predicted testcross performance of maize sister inbreds

Inbreds selfed from the same F2 or backcross population are referred to as sister inbreds. In some situations, maize (Zea mays L.) sister inbreds may not have testcross data available for best linear unbiased prediction (BLUP) of single-cross performance. This study evaluated the usefulness of BLUP and restriction fragment length polymorphism (RFLP)-based coefficients of coancestry ( f ) in predicting the testcross performance of sister inbreds. Parental contributions (p) were estimated from 70 RFLP loci for 15 inbreds that comprised three sister inbreds selfed from each of five F2 populations. Estimates of p were subsequently used to calculate RFLP-based f. Grain yield, moisture, and stalk lodging data were obtained for 2265 single crosses tested by Limagrain Genetics in multilocation trials from 1990 to 1995. Performance of the sister inbreds when crossed to several inbred testers was predicted from the performance of the tested single crosses and RFLP-based f. Correlations between predicted and observed performance, obtained with a delete-one cross-validation procedure, were erratic and mostly low for all three traits. Correspondence was poor between ranks for predicted and observed general combining ability of the sister inbreds. The results suggested that the proportion of the genome derived by a sister inbred from a given parental inbred does not solely determine its testcross performance. The failure of BLUP and RFLP-based f to consistently predict testcross performance indicated that actual field testing will continue to be necessary for preliminary evaluation of sister inbreds.

Electrical field measurements on an EPRI two-pole, 20-hp Written Pole motor

The recent introduction of the Electric Power Research Institute (EPRI) single-phase Written Pole soft-start motor may open new possibilities and marketing opportunities for rural electric cooperatives. The new single-phase high-efficiency AC motor technology promises soft-start capabilities that allow designs and application of up to 60 hp 240 V motors. This paper summarizes some of the technical aspects of the new single-phase motor technology. An actual field test and application of a Written Pole motor is also be used to compare motor starting currents and line flicker with manufacturer's literature and specifications.

Simulation of a Vehicle Impacting a Modified Thrie-Beam Guardrail

A three-dimensional finite-element simulation study, developed for the purpose of modeling the event of a compact automobile impacting a modified thrie-beam guardrail, is presented. The developed computational model has been used to simulate an actual field test that was previously conducted as part of a full-scale crash test program carried out under the auspices of FHWA. Results of the actual crash test are also used to "tune" the simulation model.

2-D frost action modeling using the segregation potential of soils

The segregation potential, SP, has been used to solve two-dimensional frost heave problems. SP-based approach to predict frost heave has been extended to 2-D problems such as freezing around chilled pipelines buried in unfrozen ground. It requires, however, the input of non-linear stress-strain-strain rate-temperature relations for characterizing the behavior of the frozen soil and an incrementally deforming mesh. Simulations of actual field tests using burial chilled pipelines were successfully performed with the newly developed 2D-SP frost action model and provide distributions of ice content, stresses and displacements. Assuming a bi-linear stress-strain relationship for the frozen soil, parametric studies have shown that frost heave was more sensitive to post-yield characteristics of the frozen soil than to the magnitude of its yield stress.

Real-time simulation of photovoltaic modules

A photovoltaic (PV) array simulator, consisting of a computer controlled d.c. power supply producing up to 100 W and associated control software, was designed and developed to generate real-time current-voltage ( I-V) output characteristic curves of photovoltaic cells under simulated conditions. The system is also capable of modelling radiation damage due to high energy particles. The system comprises a pre-regulator, a switch-mode regulator, a computer interface, and modelling and control software. The control software uses feedback of the output voltage and current to iteratively converge to the actual operating point for the connected load. Simulation results match the expected theoretical calculations well. The main advantage of the simulator is its ability to simulate different types and sizes of arrays under varying illumination and temperature using actual loads. The system can be used to study the short-term and long-term performances of PV modules and to predict end-of-life efficiency. The simulator is a far more cost effective and reliable replacement for actual field testing.

Insights on the SASW nondestructive testing method

Spectral analysis of surface waves (SASW) is a nondestructive and in-situ method used for determining the thickness and elastic properties of pavement and soil sites using the dispersion characteristics of surface waves. In this paper, computer simulations of actual surface wave field tests are used to clarify errors that may arise in experimental dispersion curves of pavement sites when the usual test and data analysis procedures of the SASW method are followed. Two aspects of these procedures are considered: (i) relative phase angle unwrapping and (ii) source-to-near-receiver distance. The results of these simulations reveal that the currently used procedures may lead to erroneous results for some sites; the simulations offer valuable insights on the underlying causes. An overview of the theoretical aspects and field procedures of the surface wave method is briefly presented. Key words: surface waves, nondestructive testing, pavements, soils, elastic modulus.

A minimal realization approach to reduced-order modelling and modal analysis for power system response signals

The authors report on a numerical scheme for compressing in parametric form small signal electromechanical responses of multimachine power systems, originating from transient stability programs (TSPs) or actual field testing. The result is achieved by using a multi-input multi-output (MIMO) minimal realization algorithm based on singular value decomposition (SVD), which can explicitly take into account the critical impact of the input interactions. The resulting parametric model is a reduced order representation of the underlying complex system, yet it is optimal (in the least-squares sense). Besides compact storage of damping information, the balanced state-space realization as such retains the principal components of the response signals, and could thus be useful for the tuning of static volt-ampere reactive (VAr) systems (SVSs) and power system stabilizers (PSSs). When it is transformed in the modal space, the model also provides insight into modal interaction mechanisms. Several examples are included for illustration purposes and other applications and improvements are also discussed. >

Transient overvoltages and overcurrents on 12.47 kV distribution lines: computer modeling results

Field tests were undertaken to study transient overvoltages and overcurrents on 12.47 kV distribution line. The computer modeling and simulation of the field tests are examined. The adaptation and refinement of the transformer, load, and line models are described. Computer simulation of the field tests using the Electromagnetic Transient Program (EMTP) gave results that are very close to the actual field tests. Also reported are results from a parametric study that were utilized to develop a simplified computer model.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An Implicit Numerical Model for the Closed-Chamber Test

Summary An implicit Lagrangean model is presented for the closed-chamber test (CCT). Pressure drops from 5, 000 to 50 psi are not uncommon during a CCT. High fluid velocities near the wellbore under high pressure gradients may lead to non-Darcy flow in the reservoir. The wellbore and the reservoir are modeled by the scalar-conservation laws of momentum and continuity that describe the physical processes—variable celerity, physical dissipation, and momentum. Rate and pressure are obtained simultaneously for the entire reservoir/wellbore system. The Lagrangean formulation permits use of the appropriate equation of state (EOS) in a given wellbore cell. Solution is by a versatile implicit numerical scheme that allows control of numerical dissipation. The automatic regridding is based on the physics of the problem. The reservoir model shows excellent agreement with the finite radial-source solution in porous media. Attributes of the model include the effects of an initial fluid column, sand failure, and a time-dependent skin. The results are in good agreement with two actual field tests from offshore Gulf of Mexico, and the deduction of transmissibility is straightforward.

逸水対策技術におけるエキスパートシステムの開発

Lost circulation (LC) is the phenomenon where circulating drilling fluid is lost to fracture or porous in the rock formation rather than returning to the surface. For drilling geothermal well, LC can be serious problem that contributes greatly to the cost of the average geothermal well and completion of the well. We studied ''The research and development of lost circulation techniques in geothermal wells'' to permit systematical lost circulation treatment undertaking committed by the New Energy and Industrial Technology Development Organization (NEDO) from 1986 to 1990, whose program consists of detection of LC analysis techniques, plugging materials, and treatment techniques. In this project, the expert system for lost circulation problems, so-called LC expert, was developed to support determination of LC treatment method for drilling engineers. The LC expert suggests drilling engineers to design the optimum LC treatment. We believe these suggestions would reduce uncertainty and mistake in decision process of field personnel. Developed LC expert designs the optimal solutions for LC treatment according to the information obtained from the LC detection tool and its data processing, knowledge base including experiences of drilling experts, properties of each plugging materials, knowledge obtained from simulation test, and knowledge from field test. It was evaluated by drilling experts and actual field tests that the LC expert inferred the LC treatment method quite adequately.

Special Issue "Fuzzy/Neural Network Applications to Dynamics and Control of Mechanical Systems". Application of Fuzzy Control to Anti-Sway-System of Container Crane.

Fuzzy control was applied to container crane to reduce the residual sway and to improve the positioning of a container. Fuzzy rules were modelled on the know-how of skillful operators, which were obtained by observing the actual loading and unloading operation of containers. The results of computer simulation test show that the remaining sway of a container was within ±50 mm and the positioning error was less than 30 mm, with which the actual field test agreed very well. Thus we achieved the anti-sway-system of the container crane with human skill by fuzzy control.

Performance verification of solidified radioactive waste using lysimeters

Accurate data on the long-term performance of the radioactive wastes in disposal systems is becoming a necessity in part because of restrictive federal and state regulations which are being promulgated. A method which provides data on the performance of buried radioactive waste forms is comprised of lysimeters. They are ideal instruments for obtaining actual field test data because when properly designed and operated they can be used to isolate and then study soil/waste systems under actual environmental conditions. The complexity of interactions under such conditions can never be completely duplicated by standard laboratory testing. This paper provides data from two instrumented, operational lysimeter arrays containing waste forms fabricated with highly loaded exchange resin materials. The lysimeters have been in operation for three years and provide both meteorological data and radionuclide content of percolating water. This paper provides data obtained from the lysimeters and discusses how these data can be used as a database for input into codes used to verify performance of buried radioactive waste forms.

Finite element formulation for transport equations in a mixed co‐ordinate system: An application to determine temperature effects on the single‐well chemical tracer test

AbstractHeterogeneous equation systems in a pair of coupled co‐ordinate systems are solved by a finite element method. The specific physical application studied is the effect of temperature on single‐well chemical tracer (SWCT) tests to measure residual oil saturation (volume fraction of immobile oil phase) remaining after waterflooding of an oil reservoir. Since temperature effects are caused by injecting cooler surface fluid down a well into a warm reservoir, the vertical temperature profile in the wellbore as well as the temperature distribution in the porous oil‐bearing layer must be considered.The entire system is modelled to account for the different transport mechanisms. However, it is expedient to divide the connected geometrical region into two model domains. The equations for each submodel are expressed in an appropriate set of co‐ordinates. The variational formulation of each model is then discussed.A significant temperature effect on the estimation of residual oil saturation occurs when the radial temperature and concentration wave propagation speeds in the porous formation are about the same. In this case the temperature gradient is located across the chemical tracer bank, causing the chemical reaction rate to vary radially. The temperature effects are demonstrated for two actual field tests in complex reservoirs.

Correlation between a laboratory impact-abrasion test and an in-situ marked-ball test

In ball milling, materials consumption by wear represents a very high production cost, and must be minimized by the proper selection of materials, especially those for balls. A simple laboratory impact-abrasion test was compared with the abrasion caused by ball mill grinding to develop a method of evaluating ferrous alloys for grinding applications. A marked balls test has been used for direct assessment of wear. For different chromium white cast irons, a good correlation was found between the relative abrasion resistance determined in the laboratory tests and in actual field tests. The laboratory test method is described in the present paper, as well as the results obtained with these experimental grade of high chromium cast irons.

EMTP-a powerful tool for analyzing power system transients

The development of the Electromagnetic Transients Program (EMTP), a general-purpose computer program for simulating high-speed transient effects in electric power systems, is briefly described. To illustrate the EMTP's capabilities, three examples of its use are presented. As part of the planning activities of the Athabasca Electric System in northern Saskatchewan, Canada, EMTP studies were done to provide recommendations on equipment characteristics and operating procedures for power line and transformer energization. These two studies were performed using the DCG/EPRI EMTP Version 1.0. The third application is to the 2000 MW high voltage direct current (HVDC) link between France and Great Britain. As part of a simulation exercise to check the protection settings and calculate the transient disturbances due to the switching-in of equipment or fault clearing near the station, the converter transformers were modeled using the EMTP saturated transformer model. Comparisons between the simulations and actual field tests are shown for the line energization and transformer switching transients studies. The accuracy of replication of the results is good.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Modeling and simulation in support of Navy operational test and evaluation

OPTEVFOR is chartered by CNO as the Navy's independent test organiza tion to conduct actual field test of new procurement systems. Prior to DOT&amp;E's issuance of new policy guidance, any test issue which OPTEVFOR could not address during OT&amp;E was left unresolved or limited comment was made based on extracts of precise technical information from pristine and less complex developmental tests. DOT&amp;E has now recognized the contribution that logically applied modeling and simulation can make toward the evaluation of new warfare systems at each decision point in the procurement and implementation cycle. This use of M&amp;S to supplement rather than replace operational testing is interpreted by DOT&amp;E as being within the spirit and intent of the law. This brings about a significant change in the way OPTEVFOR does business. To in corporate a modeling and simulation capability at OPTEVFOR, a new organization has been established: the Modeling and Simulation Branch. The M&amp;S Branch representative works with the OTD and advises him on the integration of M&amp;S into OT&amp;E, primarily to support those areas where actual testing is inadequate to provide answers to effectiveness or suitability issues, but also, to aid in OT&amp;E test design and devise new system tactics. Major systems in development now using M&amp;S to aid in early program as sessments include SSN-21, using the NUSC SIM II model, and Standard Missile (SM-2) Block IV with its series of flyout and endgame portrayal models developed through the coordination of Raytheon.

Report on bus transfer. III. Full scale testing and evaluation

For pt.II see ibid., vol.5, no.3, p.470-6 (1990). Results from selected full-scale bus transfer tests are presented. The discussion of each test includes a comparison of the actual test results with computer simulations. Actual field tests are conducted in a manner designed to mimic normal operating conditions as closely as possible. High-speed chart recorders are utilized to gather test data. Typically, the tests are performed during a major outage or just prior to the initial start-up of a new unit. After testing, the auxiliary system computer models are modified to represent as closely as possible actual operating conditions at the time of the test. >