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Basic Concepts and Relations of Aerothermodynamics
Published in Bijay K. Sultanian, Logan's Turbomachinery, 2019
The result of Equation 2.45 is also obtainable from Equation 2.21 if h1=h2. Equal enthalpy implies no change of temperature and pressure in the flow, which agrees with the original assumption of zero reaction—i.e., no pressure drop in the rotor. If the degree of reaction of a turbine stage, denoted by R, is defined as the ratio of the enthalpy drop in the rotor to the enthalpy drop in the stator plus that in the rotor—namely, R=h1−h2he−h2
Turbomachinery
Published in William S. Janna, Introduction to Fluid Mechanics, Sixth Edition, 2020
Performance of an axial-flow turbine stage is conveniently described by means of what is called degree of reaction or reaction ratio, RR. The classic definition is the ratio of static pressure drop in the rotor to the static pressure drop in the stage: RR=p1−p2p0−p2
Hydraulic Turbines
Published in V. Dakshina Murty, Turbomachinery, 2018
Comment: Degree of reaction is defined as the ratio of the static enthalpy to total (stagnation) enthalpy change across the turbine. Since the fluid is water, enthalpy change would be reflected in the pressure change across the rotor. Also, the various definitions of E, R, and ε are equivalent.
Study of Combustion Characteristics of Magnesium/Strontium Nitrate and Magnesium/Sodium Nitrate Pyrotechnics Under Low Pressure Environment
Published in Combustion Science and Technology, 2023
Zefeng Guo, Hua Guan, Chengkuan Shi, Bohuai Zhou
In order to compare the difference of burning performance and luminescence of different magnesium nitrate pyrotechnics in high altitude environment, four sets of zero oxygen balance magnesium/sodium nitrate (N) and magnesium/strontium nitrate (S) pyrotechnic mixtures were designed for this study. The flame morphology and luminescence efficiency of these four groups of samples under low-pressure environment were compared by low-pressure combustion tests. The effect of pressure on the degree of reaction was investigated using a NETZSCH STA449F3 (USA) simultaneous thermal analyzer, a scanning electron microscope, and an energy dispersive spectrometer. The results of the study provide a reference for the application of pyrotechnics in low-pressure environments.
Study of Low-Pressure Combustion and Luminescence Properties of Different Magnesium/Nitrate Pyrotechnics
Published in Combustion Science and Technology, 2023
Zefeng Guo, Hua Guan, Chengkuan Shi, Yichao Liu, Zhiwei Sun, Bohuai Zhou
The main objective of this study is to investigate the luminescence and combustion performance of magnesium/nitrate luminescent pyrotechnics in a subatmospheric environment. The effects of ambient pressure on flame structure, flame temperature, luminous intensity, and flame spectrum were analyzed by low-pressure combustion experiments. The effect of low-pressure environment on the degree of reaction was investigated by low-pressure thermal analysis experiments. We can finally obtain the following conclusions.