Periodic heat conduction in a solid homogeneous finite cylinder
ABSTRACT Analytic solution of the steady periodic, non-necessarily harmonic, heat conduction in a homogeneous cylinder of finite length and radius is given in term of Fourier transform of the fluctuating temperature field. The solutions are found for quite general boundary conditions (first, second and third kind on each surface) with the sole restriction of uniformity on the lateral surface and radial symmetry on the bases. The thermal quadrupole formalism is used to obtain a compact form of the solution that can be, with some exception, straightforwardly extended to multi-slab composite cylinders. The limiting cases of infinite thickness and infinite radius are also considered and solved.
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- "Conduction transfer function (CTF) method  is widely used for heat flow calculation of buildings for system design or system operation and control since CTF coefficients relate the desired outputs at a moment to the previous inputs through a set of coefficients . In building energy simulation packages such as DOE-2 , EnergyPlus  and BLAST  etc., CTF method is the most popular while other methods may also be used   . "
ABSTRACT: Short time step heat flow calculation of building constructions is often needed for practical applications. Conventional methods such as state-space method and root-finding method may produce unstable conduction transfer function (CTF) coefficients at short time steps, and thus result in unstable heat flow calculation through building constructions. Frequency-domain regression (FDR) method is a newly developed method for computing CTF coefficients efficiently by representing the real building construction system with equivalent polynomial s-transfer functions. Previous studies on this method mainly addressed CTF coefficients at the conventional time step of 3600s and the performance of heat flow calculation using these coefficients. This paper presents the investigation on the performance of CTF coefficients at various short time steps based on FDR method, and the performance of the heat flow calculation using these coefficients. The results show that FDR method can produce stable CTF coefficients at various time steps for most building constructions, and the calculated heat flows using these coefficients are of high accuracy.International Journal of Thermal Sciences 12/2009; 48(12):2355-2364. DOI:10.1016/j.ijthermalsci.2009.05.005 · 2.56 Impact Factor
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ABSTRACT: This paper reviews new product development projects published previously and examines how companies define their next generation of products and develop them while watching the market for potential disruptive technologies and take precautions for those with potential to influence the market place. The study includes a quantification methodology of the product development capabilities of the companies discussed in the case studies. Hypothesis testing was used to identify the relationship between the product development capabilities and the product success. From a literature search, three major capabilities of new product development were identified: technology integration, product development techniques, and watching disruptive technologiesManagement of Engineering and Technology, 1999. Technology and Innovation Management. PICMET '99. Portland International Conference on; 02/1999
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ABSTRACT: A new method based on the thermal quadrupoles technique for heat transfer modelling in multilayered slabs with heat sources is proposed. Classical thermal quadrupoles use hyperbolic functions and numerical problems occur according to the argument value that depends on thermophysical and geometrical properties as well as characteristics times. We propose a new formulation based on exponential function with negative argument. Using this formulation in the classical equivalent impedance network allows to compute efficiently the thermal behaviour of multilayered slabs with internal heat sources whatever the time and the thermophysical properties. This approach is applied in order to simulate heat transfer in three different multilayered materials with heat sources. These simulations show the capability of such a methodology to simulate time and space multiscale heat diffusion problems.International Journal of Thermal Sciences 01/2011; DOI:10.1016/j.ijthermalsci.2011.10.005 · 2.56 Impact Factor