# lec 9 - 3/min The power input is 55.2 kJ/kg of flowing 134a...

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Lec 9 Mass and Energy Balances for Devices Cont. Turbines - Devices which produce power as a result of a gas or liquid passing through a set of vanes attached to a freely rotating shaft. Ex. Hydropower Steam and gas turbines ( ) ( ) ( ) - + - + - + + = 2 1 2 2 2 1 2 1 2 0 z z g V V h h m W Q cv cv &

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Ex. Hot combustion gases modeled as air and as an ideal gas enters a turbine at 145 lbf/in 2 , at 2700 °R and mass flow rate of .22 lb/s. The gases exit at 29 lbf/in 2 and 1620 °R. Heat transfer rate for the turbine is 14 Btu/s. Determine the turbine power output in hp
Compressors and pumps ( ) 2 1 0 h h m W Q cv cv - + + = &

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Ex. Refrigerant 134a enters A/C compressor at 3.2 bar, 10°C and is compressed at steady state to 10 bar and 70 °C. The inlet volumetric flow rate of 134a is 3.0 m

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Unformatted text preview: 3 /min. The power input is 55.2 kJ/kg of flowing 134a. Neglect kinetic and potential effects. Determine heat transfer rate in kW. Heat Exchangers Many types: Often have multiple inlets and outlets ( ) ( ) ∑ ∑ + +- + + + + = e e e e e i i i i i cv cv z g V h m z g V h m W Q 2 2 2 2 & & & & Ex: Electronic components of a computer consume 0.1kW of electrical power. A 25 W cooling fan at an inlet to the computer is used to prevent overheating. At steady state air enters 20°C and 1 bar and exits the computer at 35°C. The computer case does not transfer much heat. Determine the volumetric flow rate entering the fan....
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lec 9 - 3/min The power input is 55.2 kJ/kg of flowing 134a...

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