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Jet Engine Performance
The behavior of a jet engine and its effect both on the aircraft and the environment is categorized into different engineering areas or disciplines. The understanding of how a particular fuel flow produces a definite amount of thrust at a particular point in the flight envelope is called jet engine performance, while the emissions come under a group called combustion, and the origin of vibrations transmitted to the airframe comes under an area called rotor dynamics. Performance is the subject of a specialized discipline within aero engine design and development. In fixed-wing aircraft driven by one or more jet engines, certain aspects of performance such as thrust relate directly to the safe operation of the aircraft whereas other aspects of the engine operation such as noise and engine emissions affect the environment. The thrust, noise and emission elements of the operation of a jet engine are of vital importance in the takeoff phase of operation of the aircraft. The thrust a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed-wing Aircraft
A fixed-wing aircraft is a heavier-than-air flying machine, such as an airplane, which is capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are distinct from rotary-wing aircraft (in which the wings form a rotor mounted on a spinning shaft or "mast"), and ornithopters (in which the wings flap in a manner similar to that of a bird). The wings of a fixed-wing aircraft are not necessarily rigid; kites, hang gliders, variable-sweep wing aircraft and airplanes that use wing morphing are all examples of fixed-wing aircraft. Gliding fixed-wing aircraft, including free-flying gliders of various kinds and tethered kites, can use moving air to gain altitude. Powered fixed-wing aircraft (airplanes) that gain forward thrust from an engine include powered paragliders, powered hang gliders and some ground effect vehicles. Most fixed-wing aircraft are flown by a pilot on board the craft, but some ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core Size
Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central part of a fruit * Hydrophobic core, the interior zone of a protein * Nuclear reactor core, a portion containing the fuel components * Pit (nuclear weapon) or core, the fissile material in a nuclear weapon * Semiconductor intellectual property core (IP core), is a unit of design in ASIC/FPGA electronics and IC manufacturing * Atomic core, an atom with no valence electrons Geology and astrophysics * Core sample, in Earth science, a sample obtained by coring ** Ice core * Core, the central part of a galaxy; see Mass deficit * Core (anticline), the central part of an anticline or syncline * Planetary core, the center of a planet ** Earth's inner core Earth's inner core is the innermost geologic layer of planet Earth. It is primarily a so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilonewton
The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after Isaac Newton in recognition of his work on classical mechanics, specifically Newton's second law of motion. Definition A newton is defined as 1 kg⋅m/s (it is a derived unit which is defined in terms of the SI base units). One newton is therefore the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in the direction of the applied force. The units "metre per second squared" can be understood as measuring a rate of change in velocity per unit of time, i.e. an increase in velocity by 1 metre per second every second. In 1946, Conférence Générale des Poids et Mesures (CGPM) Resolution 2 standardized the unit of force in the MKS system of units to be the amount needed to accelerate 1 kilogram of mass at the rate o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound-force
The pound of force or pound-force (symbol: lbf, sometimes lbf,) is a unit of force used in some systems of measurement, including English Engineering units and the foot–pound–second system. Pound-force should not be confused with pound-mass (lb), often simply called ''pound'', which is a unit of mass, nor should these be confused with foot-pound (ft⋅lbf), a unit of energy, or pound-foot (lbf⋅ft), a unit of torque. Definitions The pound-force is equal to the gravitational force exerted on a mass of one avoirdupois pound on the surface of Earth. Since the 18th century, the unit has been used in low-precision measurements, for which small changes in Earth's gravity (which varies from equator to pole by up to half a percent) can safely be neglected. The 20th century, however, brought the need for a more precise definition, requiring a standardized value for acceleration due to gravity. Product of avoirdupois pound and standard gravity The pound-force is the product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reynolds Number
In fluid mechanics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow ( eddy currents). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of cavitation. The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing. It is used to predict the transition from laminar to turbulent flow and is used in the scaling of similar but different-sized flow situations, such as between an aircraft model in a wind tunnel and the full-size ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbine Map
Each turbine in a gas turbine engine has an operating map. Complete maps are either based on turbine rig test results or are predicted by a special computer program. Alternatively, the map of a similar turbine can be suitably scaled. Description A turbine map shows lines of percent corrected speed (based on a reference value) plotted against the x-axis which is pressure ratio, but deltaH/T (roughly proportional to temperature drop across the unit/component entry temperature) is also often used. The y-axis is some measure of flow, usually non-dimensional flow or corrected flow, but not actual flow. Sometimes the axes of a turbine map are transposed, to be consistent with those of a compressor map. As in this case, a companion plot, showing the variation of isentropic (i.e. adiabatic process, adiabatic) or polytropic efficiency, is often also included. The turbine may be a transonic unit, where the throat Mach number reaches speed of sound, sonic conditions and the turbine becomes tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compressor Map
A compressor map is a chart which shows the performance of a turbomachinery compressor. This type of compressor is used in gas turbine engines, for supercharging reciprocating engines and for industrial processes, where it is known as a dynamic compressor. A map is created from compressor rig test results or predicted by a special computer program. Alternatively the map of a similar compressor can be suitably scaled. This article is an overview of compressor maps and their different applications and also has detailed explanations of maps for a fan and intermediate and high-pressure compressors from a three-shaft aero-engine as specific examples. Compressor maps are an integral part of predicting the performance of gas turbine and turbocharged engines, both at design and off-design conditions. They also serve a critical purpose in selecting the correct compressors for industrial processes. Fans and turbines also have operating maps, although the latter are significantly different in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
