expansion ratio


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expansion ratio

[ik′span·shən ‚rā·shō]
(fluid mechanics)
For the calculation of the mass flow of a gas out of a nozzle or other expanding duct, the ratio of the nozzle exit section area to the nozzle throat area, or the ratio of final to initial volume.
(mechanical engineering)
In a reciprocating piston engine, the ratio of cylinder volume with piston at bottom dead center to cylinder volume with piston at top dead center.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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Newly developed from the current MZR 1.3L DOHC aluminum engine, the naturally-aspirated MZR 1.3L Miller-cycle engine employs delayed closing of the intake valves in order to reduce pumping losses and improve thermal efficiency through a higher expansion ratio. Intake valve timing is optimized by the Sequential Valve Timing System to provide improved fuel efficiency over the current MZR 1.3L engine when cruising and accelerating.
Previous investigations on foaming via supercritical C[O.sub.2] have indicated that the expansion ratio, [kappa], is found to be in the 1-50 range and varies with the type of polymer, operating conditions and processing geometries [27].
This paper presents a comparative study on hydrodynamic behaviours such as minimum fluidization velocity ([U.sub.mf]) and/spouting velocity ([U.sub.ms]), pressure drop ([DELTA]p), bed expansion ratio (R), bed fluctuation ratio (r), and fluidization index (FI) for both the fluidized and spouted bed using fine particles.
The scientists optimized the formulation based on what they thought would be desirable physical attributes for an RTE snack, including its expansion ratio, bulk density and hardness.
In addition, Honda has a goal to improve fuel efficiency by 20% over 2005 levels for its revolutionary high expansion ratio engine that variably controls the engine's stroke length during the intake/compression and expansion/exhaust processes.
There are still a limited number of reports on open-cell thermoplastic foam prepared by physical foam injection molding because the conventional microcellular foam injection molding could not produce a higher expansion ratio. A high expansion ratio is needed to reduce the thickness of the cell wall and to enhance its cell-opening.
Expansion ratio and half-life were measured upon varying the temperature and chamber pressure.
Such attributes as water activity, expansion ratio, color and texture were evaluated by the scientists.
The other objective is to investigate the effect of long-chain branching on the foamability of the modified PP by a one-step compression--molding process, and the studies focuses on the cell density, expansion ratio, and cellular structure.
The use of this technique allows studying foams with different chemical compositions but keeping a constant expansion ratio. Producing these foams using the conventional compression molding technique would be a difficult task because changing the composition also affects the expansion ratio.