The rotary air preheaters at the Moss Landing power plant have the following geometry and operating.

The rotary air preheaters at the Moss Landing power plant
have the following geometry and operating conditions: 14.63-m disk diameter
with Ah = Ac = 31,120 m2 /unit, m_ gas m_
air = 340 kg/s per preheater, effectiveness ”  =
65%, Mw = 1121 kg/m3 of total volume, csteel =
460:6 J/kg  K, cair  cgas = 1026
J/kg  K, and the matrix air flow length = 1.52 m. The preheater rotates at 48
rev/h. What are the disk heat capacity rate ratio Cr * and the disk NTUo? What
is the average air-side convective conductance? Assume that hc  hh.
Explain why you would neglect longitudinal
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The rotary air preheaters at the Moss Landing power plant
have the following geometry and operating conditions: 14.63-m disk diameter
with Ah = Ac = 31,120 m2 /unit, m_ gas m_
air = 340 kg/s per preheater, effectiveness ”  =
65%, Mw = 1121 kg/m3 of total volume, csteel =
460:6 J/kg  K, cair  cgas = 1026
J/kg  K, and the matrix air flow length = 1.52 m. The preheater rotates at 48
rev/h. What are the disk heat capacity rate ratio Cr * and the disk NTUo? What
is the average air-side convective conductance? Assume that hc  hh.
Explain why you would neglect longitudinal conduction in the wall for this
problem. In this case, the C of Eq. (5.122) is assumed as zero.

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