Experimental evaluation of a TF30-P-3 turbofan engine in an altitude facility: Effect of steady-state temperature distortion

The effects of circumferential distortion of the total temperature entering 25, 50, and 75 percent of the inlet circumferential annulus of a turbofan engine were determined. Complete compressor stall resulted from distortions of from 14 to 20 percent of the face averaged temperature. Increasing the temperature level in one sector resulted in that sector moving toward stall by decreasing the equivalent rotor speeds while the pressure ratio remained approximately constant. Stall originated as a rotating zone in the low-pressure compressor which resulted as a terminal stall in the high-pressure compressor. Decreasing the Reynolds number index to 0.25 from 0.5 reduced the required distortion for stall by 50 percent for the conditions investigated

Performance and stall limits of a YTF30-P-1 turbofan engine with uniform inlet flow

Performance and stall limits of YTF30-P-1 turbofan engine with uniform compressor inlet flo

An engineering feasibility study of an orbiting scanning radiometer

Engineering feasibility study of lunar orbiting optical scanning radiometer

Combined pressure and temperature distortion effects on internal flow of a turbofan engine

An additional data base for improving and verifying a computer simulation developed by an engine manufacturer was obtained. The multisegment parallel compressor simulation was designed to predict the effects of steady-state circumferential inlet total-pressure and total-temperature distortions on the flows into and through a turbofan compression system. It also predicts the degree of distortion that will result in surge of the compressor. The effect of combined 180 deg square-wave distortion patterns of total pressure and total temperature in various relative positions is reported. The observed effects of the combined distortion on a unitary bypass ratio turbofan engine are presented in terms of total and static pressure profiles and total temperature profiles at stations ahead of the inlet guide vanes as well as through the fan-compressor system. These observed profiles are compared with those predicted by the complex multisegment model. The effects of relative position of the two components comprising the combined distortion on the degree resulting in surge are discussed. Certain relative positions required less combined distortion than either a temperature or pressure distortion by itself

Uniform engine testing program. Phase 1: NASA Lewis Research Center participation

Two jet engines were tested under identical conditions in a variety of altitude and ground level facilities as a means to correlating these facilities. Two J57-19W turbojet engines were tested in an altitude test facility. The test results are summarized

Delivering authentic online practical science teaching – geoscience perspectives from the OpenScience Laboratory

Teaching practical science at a distance is challenging – how do you give students studying online a meaningful practical experience? In July 2013, the Open University (OU) launched the Wolfson OpenScience Laboratory (OSL) to deliver a wide a range of authentic practical science activities for their distance learning undergraduates. Prompted by the recognition that modern science is increasingly conducted via a computer screen (e.g. remote sensing, Martian fieldwork), the OSL presents a variety of opportunities for students to observe, investigate, gather and analyse data. The rationale is to foster problem-based, active learning, which has been proven effective by numerous studies. Simulation is kept to a minimum; most activities either generate or use real data, with authentic anomalies and ‘noise’ included – an aspect valued by the students. Geoscience is rooted in raw data collected during practical investigations, notably fieldwork. A key skill is observation, so the OSL includes digital collections of minerals, rocks and fossils, as zoomable, high resolution images and 360° videos for the 3D perspective. The Virtual Microscope enables petrographic examination of thin sections using high-quality zoomable images, in both plane- and cross polarised light, with rotation of the sample for certain points of interest. There is a virtual field trip based in a multi-user virtual environment (MUVE), as well as an exercise on maps and landforms. Developed primarily for OU undergraduates, many of the assets in the OSL are being made more openly accessible, with free registration. We are developing partnerships with other universities and schools, both as users and contributors to further assets (e.g. thin section collections). We have also gathered feedback from several surveys of OU undergraduates, as well as external users. Feedback on the pedagogical aspects of the OSL is broadly positive, with some assets (e.g. the virtual microscope) garnering particular praise; respondents value the potential for interaction with experts but also desire an explicit connection to the materials’ original field context. However, technological issues at times present a barrier to learning – perhaps reflecting the high diversity of OU cohorts, especially in terms of their individual hardware, software and IT skills. Some students resent the time investment required to master specialised scientific software, though it could be argued that acquiring such IT skills is an essential part of practising modern science

Summary of recent investigations of inlet flow distortion effect on engine stability

A review is presented of recent experimental results, analytical procedures and test techniques employed to evaluate the effects of inlet flow distortion on the stability characteristics of representative afterburning turbofan and turbojet compression systems. Circumferential distortions of pressure and temperature, separately and in combination are considered. Resulting engine sensitivity measurements are compared with predictions based on simplified parallel compressor models and with several distortion descriptor parameters

Infrared system studies for the earth resource program Final report

Obtaining terrain surface temperatures from radiances measured in orbi

Surface-based constraints on target selection and distractor rejection: Evidence from preview search

In preview search when an observer ignores an early appearing set of distractors, there can subsequently be impeded detection of new targets that share the colour of this preview. This “negative carry-over effect” has been attributed to an active inhibitory process targeted against the old items and inadvertently their features. Here we extend negative carry-over effects to the case of stereoscopically defined surfaces of coplanar elements without common features. In Experiment 1 observers previewed distractors in one surface (1000 ms), before being presented with the target and new distractors divided over the old and a new surface either above or below the old one. Participants were slower and less efficient to detect targets in the old surface. In Experiment 2 in both the first and second display the items were divided over two planes in the proportion 66/33% such that no new planes appeared following the preview, and there was no majority of items in any one plane in the final combined display. The results showed that participants were slower to detect the target when it occurred in the old majority surface. Experiment 3 held constant the 2D properties of the stimuli while varying the presence of binocular depth cues. The carry-over effect only occurred in the presence of binocular depth cues, ruling out any account of the results in terms of 2-D cues. The results suggest well formed surfaces in addition to simple features may be targets for inhibition in search