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If HV is first expressed in N/mm 2 (MPa), or otherwise by converting from kgf/mm 2, then the tensile strength (in MPa) of the material can be approximated as σ u ≈ HV/ c, where c is a constant determined by yield strength, Poisson's ratio, work-hardening exponent and geometrical factors – usually ranging between 2 and 4. [9]
In aeronautical engineering, overall pressure ratio, or overall compression ratio, is the amount of times the pressure increases due to ram compression and the work done by the compressor stages. The compressor pressure ratio is the ratio of the stagnation pressures at the front and rear of the compressor of a gas turbine .
The tables below have been calculated using a heat capacity ratio, , equal to 1.4. The upstream Mach number, M 1 {\displaystyle M_{1}} , begins at 1 and ends at 5. Although the tables could be extended over any range of Mach numbers, stopping at Mach 5 is typical since assuming γ {\displaystyle \gamma } to be 1.4 over the entire Mach number ...
Compressor characteristic is a mathematical curve that shows the behaviour of a fluid going through a dynamic compressor.It shows changes in fluid pressure, temperature, entropy, flow rate etc.) with the compressor operating at different speeds.
A simplified version of the definition is: The k v factor of a valve indicates "The water flow in m 3 /h, at a pressure drop across the valve of 1 kgf/cm 2 when the valve is completely open. The complete definition also says that the flow medium must have a density of 1000 kg/m 3 and a kinematic viscosity of 10 −6 m 2 /s, e.g. water. [clarify]
The engine pressure ratio (EPR) is the total pressure ratio across a jet engine, measured as the ratio of the total pressure at the exit of the propelling nozzle divided by the total pressure at the entry to the compressor. [1] Jet engines use either EPR or compressor/fan RPM as an indicator of thrust. [2]
The ratios were obtained using the criterion that choked flow occurs when the ratio of the absolute upstream pressure to the absolute downstream pressure is equal to or greater than ([+] /) / (), where is the specific heat ratio of the gas. The minimum pressure ratio may be understood as the ratio between the upstream pressure and the pressure ...
A low pressure ratio fan (such as that used on a high bypass ratio turbofan) has a range of working lines. At high flight speeds, the ram pressure ratio factors up the cold nozzle pressure ratio, causing the nozzle to choke. Above the choking condition, the working lines tend to coalesce into a unique steep straight line.