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A research and laboratory kit of Thermindex temperature indicating paints has been introduced by Synthetic and Industrial Finishes. The paints are temperature‐sensitive compounds…
Abstract
A research and laboratory kit of Thermindex temperature indicating paints has been introduced by Synthetic and Industrial Finishes. The paints are temperature‐sensitive compounds which indicate by a sharp, clear‐cut change of colour when the temperature of a surface has reached or exceeded a pre‐determined value. An accurate picture of the temperature of a surface can therefore be seen at a glance.
Massimo Miozzi, Alessandro Capone, Christian Klein and Marco Costantini
The purpose of this study is the characterization of the dramatic variation in the flow scenario occurring at incipient stall conditions on a NACA0015 hydrofoil at moderate…
Abstract
Purpose
The purpose of this study is the characterization of the dramatic variation in the flow scenario occurring at incipient stall conditions on a NACA0015 hydrofoil at moderate Reynolds numbers via the experimental analysis of time- and space-resolved skin-friction maps. The examined flow conditions are relevant for a variety of applications, including renewable energy production and unmanned and micro-aerial vehicles.
Design/methodology/approach
Grounding on the global temperature data acquired via temperature-sensitive paint, the proposed methodology adopts two approaches: one to obtain time-resolved, relative skin-friction vector fields by means of an optical-flow-based algorithm and the other one to extract quantitative, time-averaged skin-friction maps after minimization of the dissimilarity between the observed passive transport of temperature fluctuations and that suggested by the Taylor hypothesis.
Findings
Through the synergistic application of the proposed methods, the time-dependent evolution of the incipient stall over the hydrofoil suction side is globally described by firstly identifying the trailing edge separation at an angle of attack (AoA) AoA = 11.5°, and then by capturing the onset of upstream oriented, mushroom-like structures at AoA = 13°. The concomitant occurrence of both scenarios is found at the intermediate incidence AoA = 12.2°.
Originality/value
The qualitative, time-resolved skin-friction topology, combined with the quantitative, time-averaged distribution of the streamwise friction velocity, enables to establish a portrait of the complex, three-dimensional, unsteady scenario occurring at the examined flow conditions, thus providing new, fundamental information for a deeper understanding of the incipient stall development and for its control.
Details
Keywords
In GB patent 2283 489, Delta Resins Ltd describes infrared curing of resins, resin systems and other catalysed systems. Infrared radiations are at the temperature corresponding to…
Abstract
In GB patent 2283 489, Delta Resins Ltd describes infrared curing of resins, resin systems and other catalysed systems. Infrared radiations are at the temperature corresponding to the peak frequency characteristic of the spectrum of the curing reaction of the particular system. Irradiation may take place in an oven with electrical elements controllable to attain temperatures the to nearest 0.1 °C, or in catalytic gas burners to thus provide infrared radiation of the optimum frequency. An example of curing all epoxy resin systems is given. Curing times of about ten minutes are achieved.
The Quality of holes drilled in multilayer printed circuit boards and the usable life of a drill are a function of the drilling speed and feed rate per revolution. Investigations…
Abstract
The Quality of holes drilled in multilayer printed circuit boards and the usable life of a drill are a function of the drilling speed and feed rate per revolution. Investigations have shown that, as the RPM is reduced and the feed rate per revolution (bite) increased, both hole quality and drill life are improved. The temperatures generated during the drilling process have been measured as a function of RPM and feed rate, and shown to be the cause of the variation in drill life and hole quality. Experimental data substantiating these results is presented. Acknowledgement is made to the Institute of Printed Circuits for their permission to reproduce this paper.
EVER since the beginning of aircraft construction sheet metal fittings have been made by means of oxy‐acetylene welding; usually in the form of fittings connecting parts of…
Abstract
EVER since the beginning of aircraft construction sheet metal fittings have been made by means of oxy‐acetylene welding; usually in the form of fittings connecting parts of plywood fuselages or of wooden wings. Later, strut fittings followed in which U‐shaped sheets or flanges were welded to tubes. Control‐gear parts were made from tubes, bushes and sheet webs. Afterwards, whole fuselages and control components, such as tail plane structures and elevators, became welded tubular structures. All attachments required for engines, undercarriages, wings and installed components were welded up, according to the design practice preferred.
A Conference at Southampton University concerned with the latest developments, experiences and future thinking on dynamic vibration isolation and absorption applicable to…
Abstract
A Conference at Southampton University concerned with the latest developments, experiences and future thinking on dynamic vibration isolation and absorption applicable to machinery, equipment and structures from the miniature to the massive, will be held on Wednesday, September 8, 1982. Papers are now called for.
The factors which should be considered when contemplating windshield design are outlined, and various levels of high performance vehicles are defined. The relationship between…
Abstract
The factors which should be considered when contemplating windshield design are outlined, and various levels of high performance vehicles are defined. The relationship between environment and design criteria is discussed and the author introduces some of the unique glasses in current use.
Mayurkumar Ashwinbhai Makhesana and Kaushik M. Patel
The quality of the surface being machined and tool life are greatly affected by heat generated during machining. Abundant use of cutting fluid leads to higher production rates and…
Abstract
Purpose
The quality of the surface being machined and tool life are greatly affected by heat generated during machining. Abundant use of cutting fluid leads to higher production rates and a threat for environment and worker’s health. Hence, the need is to identify eco-friendly lubricants. The purpose of the current work is to investigate the effects of solid lubricants (boric acid and molybdenum disulphide) mixed with oil during turning of EN-31 using cemented carbide tools. The concentration of solid lubricants in oil is varied to analyze output parameters such as surface roughness, process temperature, power consumption and tool wear.
Design/methodology/approach
EN 31 steel material is machined at various cutting speeds and constant feed and depth of cut to determine the effects of dry, wet and solid lubricant assisted machining.
Findings
Experimental study revealed that the solid lubricants performed better while machining and therefore it may be considered as environment friendly and cost effective way of lubrication as compared to flood cooling.
Research limitations/implications
The work can be extended to identify the effects of solid lubricants on micro hardness and cutting force.
Practical implications
From the findings of the work, solid lubricants may be considered as suitable choice as compared to fluid cooling because it improves process performance without much affecting the environment and worker’s health.
Originality/value
So far the use of solid lubricants in machining is limited. The results of the work will be useful to explore various efficient way to apply solid lubricants.
Details
Keywords
Vinay C.A. and Kumar G.N.
Development or upgradation of airplanes requires many different analyses, e.g. thermal, aerodynamic, structural and safety. Similar studies were performed during configuration…
Abstract
Purpose
Development or upgradation of airplanes requires many different analyses, e.g. thermal, aerodynamic, structural and safety. Similar studies were performed during configuration change design of commuter category aircraft equipped with pusher turboprop engines. In this paper, thermo-fluid analyses of interactions of the new propulsion system in tractor configuration with selected elements of airplane skin are carried out. This study aims to check the airplane skin material, and its geometry, including the Plexiglas passenger window material degradation, due to hot exhaust gas plume impingement. The impact of change in exhaust stub angle and asymmetric inboard-outboard stubs on the jet thrust at various flight operating conditions like minimum off-route altitude and cruise performance is assessed.
Design/methodology/approach
Commercial software-based numerical models were developed. In the first stage, heat and fluid flow analysis was performed over a twin-engine airplane’s nacelle, wing and center fuselage with its powerplant mounted in the high wing configuration. Subsequently, numerical simulations of thermal interactions between the hot exhaust gases, which leave the exhaust system close to the nacelle, flaps and the center fuselage, were estimated for various combinations of exhaust stub angles with asymmetry between inboard-outboard stubs at different airplane configurations and operating conditions.
Findings
The results of the simulations are used to recommend modifications to the design of the considered airplane in terms of material selection and/or special coatings. The importance and impact of exhaust jet thrust on the overall aircraft performance are investigated.
Originality/value
The advanced numerical model for the exhaust jet-airplane skin thermal interaction was developed to estimate the temperature effects on the propeller blades and aircraft fuselage surfaces during different flight operating conditions with multiple combinations of stub orientations.
Details