Conjugated laminar forced convection in ducts with periodic variation of inlet temperature

1990 ◽  
Vol 11 (4) ◽  
pp. 311-320 ◽  
Author(s):  
W.S. Kim ◽  
M.N. Özişik
Keyword(s):  
Forced Convection ◽  
Periodic Variation ◽  
Inlet Temperature ◽  
Laminar Forced Convection

Unsteady Laminar Forced Convection in Ducts With Periodic Variation of Inlet Temperature

1990 ◽  
Vol 112 (4) ◽  
pp. 913-920 ◽  
Author(s):  
S. Kakac ◽  
W. Li ◽  
R. M. Cotta
Keyword(s):  
Experimental Study ◽  
Forced Convection ◽  
Integral Transform ◽  
Periodic Variation ◽  
Inlet Temperature ◽  
General Boundary Condition ◽  
Thermal Capacitance ◽  
Phase Lags ◽  
Capacitance Effects ◽  
Laminar Forced Convection

A theoretical and experimental study of laminar forced convection in the thermal entrance region of a rectangular duct, subjected to a sinusoidally varying inlet temperature, is presented. A general boundary condition of the fifth kind that accounts for both external convection and wall thermal capacitance effects is considered, and an analytical solution is obtained through extending the generalized integral transform technique. The variations of amplitudes and phase lags of centerline and bulk temperatures are determined as functions of modified Biot number, fluid-to-wall thermal capacitance ratio, and dimensionless inlet frequency. An apparatus has been designed, built, and used for the experimental study to provide validation of the mathematical modeling employed. Good agreement is obtained when the nonuniform sinusoidally varying inlet temperature profile obtained by experiments is incorporated into the theoretical model.

Laminar forced convection performance of non-Newtonian water-CNT/Fe3O4 nano-fluid inside a minichannel hairpin heat exchanger: Effect of inlet temperature

2019 ◽  
Vol 354 ◽  
pp. 247-258 ◽  
Author(s):  
W.I. Liu ◽  
Abdullah A.A.A. Al-Rashed ◽  
Ali Sulaiman Alsagri ◽  
Boshra Mahmoudi ◽  
Amin Shahsavar ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Forced Convection ◽  
Inlet Temperature ◽  
Nano Fluid ◽  
Laminar Forced Convection

Turbulent Forced Convection Inside a Parallel-Plate Channel With Periodic Variation of Inlet Temperature

1989 ◽  
Vol 111 (4) ◽  
pp. 882-888 ◽  
Author(s):  
W. S. Kim ◽  
M. N. O¨zis¸ik
Keyword(s):  
Eigenvalue Problem ◽  
Forced Convection ◽  
Parallel Plate ◽  
Periodic Variation ◽  
Bulk Temperature ◽  
Inlet Temperature ◽  
Complex Eigenvalue ◽  
Phase Lag ◽  
Constant Wall Temperature ◽  
Plate Channel

The analysis of heat transfer in turbulent forced convection subject to a periodically varying inlet temperature leads to a nonclassical Sturm–Liouville type eigenvalue problem for which no known solution is available. In this work a new methodology is developed to alleviate the need for the solution of a complex eigenvalue problem in the analysis of turbulent forced convection inside a parallel-plate channel with a periodicially varying inlet temperature and a uniform constant wall temperature. In this approach, the problem is transformed to the solution of a system of coupled ordinary differential equations in the complex domain, which could readily be solved. For the cases considered it is demonstrated that the solutions obtained from the decoupled system, referred to as the lowest-order solution, produce sufficiently accurate results. The variation of the amplitudes and phase lag of both fluid bulk temperature and the wall heat flux along the channel is investigated and a simple approximate analytic formula is developed for determining the variation of the phase lag for the bulk temperature along the channel.

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