Q3: Streams of methane and air (79 mole% N2, the balance O₂) are combined at the
inlet of a combustion furnace preheater. The pressures of each stream are measured
with open-end mercury manometers, the temperatures are measured with resistance
thermometers, and the volumetric flow rates are measured with orifice meters.
Measurement point 1
Data:
Flowmeter 1: V₁ = 947 m³/h
Flowmeter 2: V₂ = 195 m³/min
Manometer 1: h₁ = 232 mm
Manometer 2: h₂ = 156 mm
Manometer 3: h3 = 74 mm
Resistance thermometer 1: r₁ = 26.159 ohms
Resistance thermometer 2: r₂ = 26.157 ohms
Resistance thermometer 3: r3 = 44.789 ohms
Atmospheric pressure: A sealed-end mercury manometer reads h = 29.76 inches
CH₂
Air
Measurement point 2
PREHEATER
Measurement point 3
The resistance thermometers were calibrated by measuring their resistances at the
freezing and boiling points of water, with the following results:
T = 0 °C:
r = 23.624 ohms
T = 100 °C:
r = 33.028 ohms
A straight-line relationship between T and r may be assumed.