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An analytical solution for the nonlinear frequency response of radiant heat transfer
Author(s) -
Blum Edward H.
Publication year - 1965
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690110331
Subject(s) - enclosure , nonlinear system , frequency response , harmonics , heat transfer , perturbation (astronomy) , mechanics , amplitude , mathematical analysis , thermal conduction , control theory (sociology) , mathematics , physics , classical mechanics , thermodynamics , optics , engineering , computer science , quantum mechanics , voltage , artificial intelligence , telecommunications , electrical engineering , control (management)
An analytical solution is presented for the nonlinear frequency response of a system in which radiant heat transfer is coupled with conduction. The model is that of an object inside an evacuated enclosure whose wall temperature oscillates about a mean. A perturbation analysis solves the describing equations for oscillatory amplitudes less than one‐tent the mean wall temperature. An exact solution to a Ricatti differential equation verifies the perturbation analysis. These solutions show that, contrary to linear experience, the average object temperature over an oscillatory cycle exceeds the mean at the wall. The complete solution for the frequency response can be divided into three regimes. In the first, at low frequencies, all response is truly linear. In the second, higher harmonics become important, but the response remains that of a lumped parameter systems. In the third, response changes with distance from the object surface and the response at the surface dominates. Nonlinearities are important in the second and third regimes. The solution has several applications.