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2 years ago

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An electrical heater is a form of sensible heating process, and heats 0.1 m/s of air from 15°C and 80% RH to 50°C? The barometri

c pressure is 101.325 kPa. Using the psychrometric chart given, determine the heater wattage.

1 answer:

GREYUIT [131]2 years ago

5 0

Answer:

heater wattage = 4.32 kW

Explanation:

given data

volume flow rate of air = 0.1 m³/s

temperature t1 = 15°C

temperature t2 = 50°C

relative humidity RH = 80%

pressure = 101.325 kPa

to find out

heater wattage

solution

we will get here h value from psychometric chart with the help of temperature

that is

h1 = 37 kJ/kg

and

h2 = 73 kJ/kg

and v1 = 0.829 m³/kg

so here heater wattage formula is

heater wattage = m ( h2 -h1) ......1

here m is

m = V/v1 = 0.1 / 0.819 = 0.12 kg/s

so from equation 1

heater wattage = 0.12 ( 75 -39 )

heater wattage = 4.32 kW

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$-v_{2(a)} =2v_{1} =4.555ft^3/lb\\v_{g}$

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$E_{E}$ = 0.431

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True stress $\alpha _{T}$ = 460 ( 1 + 0.431)

True stress $\alpha _{T}$ = 460 (1.431)

True stress $\alpha _{T}$ = 658.26 Mpa

Therefore, the true stress at fracture is 658.26 Mpa

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