Question

Two AISI 304 stainless steel plates 10 mm thick are subjected to a contact pressure of 1 bar under vacuum conditions for which there is an overall temperature drop of 110°C across the plates. (a) What is the heat flux through the plates? (b) What is the temperature drop across the contact plane? Use R"t,c=15 x 10-4 m2·K/W and evaluate the properties of stainless steel at 400 K.

Answer 1

Step-by-step explanation:

First calculate

(a)

R₁=
`(L)/(k)`

R₁= 0.01/16.6

=6.024*10⁻⁴ m² . K/W

R₁=R₂=6.024*10⁻⁴ m² . K/W

The contact thermal resistance of AISI 304 stainless steel

`R_(contact)`= 15*10⁻⁴ m² . K/W

R=R₁+R₂+
`R_(contact)`

R=6.024*10⁻⁴+15*10⁻⁴ +6.024*10⁻⁴

R=27.048 *10⁻⁴ m² . K/W

Calculate the rate of heat transfer

q=ΔT/R

=110/(27.048 *10⁻⁴)

q= 40668.44 W/m²

(b)

Calculate the difference of temperature across the plate

`(ΔT_(contact) )/(ΔT) =(R_(contact) )/(R)`

ΔT=110*
`(15*10^(-4) )/(27.048*10^(-4) )`

ΔT=61.002 K