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"This book presents the theory of periodic conjugate heat transfer in a detailed way. The effects of thermophysical properties and geometry of a solid body on the commonly used and experimentally determined heat transfer coefficient are analytically presented from a general point of view. The main objective of the book is a simplified description of the interaction between a solid body and a fluid as a boundary value problem of the heat conduction equation for the solid body. At the body surface, the true heat transfer coefficient is composed of two parts, the true mean value resulting from the solution of the steady state heat transfer problem and a periodically variable part, the periodic time and length to describe the oscillatory hydrodynamic effects. The second edition is extended by (i) the analysis of stability boundaries in helium flow at supercritical conditions in a heated channel with respect to the interaction between a solid body and a fluid, (ii) a periodic model and a method of heat transfer simulation in a fluid at supercritical pressure and (iii) a periodic quantum-mechanical model for homogeneous vapor nucleation in a fluid with respect to nanoscale effects."

"Manajemen kalor sangat diperlukan dalam rangka menjaga keberlangsungan operasi dan memperpanjang umur pemakaian instalasi industri. Bermacam-macam peralatan dikembangkan untuk mengkarakterisisasi fenomena panas. Dalam disertasi ini, pembahasan difokuskan pada pengembangan metode pengukuran heat flux sumber panas dan konduktivitas panas bahan berbasis pendekatan Inverse Heat Conduction Problem (IHCP) 2D. Permasalahan konduksi panas untuk plat 2D dalam keadaan steady dimodelkan dengan menggunakan metode beda hingga. Dengan menggunakan data suhu hasil pengukuran experimental, pengukuran heat flux dan konduktivitas panas dilakukan melalui penyelesaian permasalahan inverse menggunakan Conjugate Gradient Method (CGM). Metode pengukuran ini membutuhkan perangkat hardware dan software. Perangkat hardware berupa plat tembaga tipis dan sistem instrumentasi untuk memonitor distribusi suhu plat. Perangkat software berupa pemrograman dalam bahasa MatLAB yang dikembangkan untuk menyelesaikan IHCP. Keunggulan dari metode baru ini adalah dapat mengukur heat flux dengan luasan berapapun dan jenis sumber panas apapun. Untuk pengukur konduktivitas panas, plat tembaga diganti dengan spesimen bahan plat yang akan dicari konduktivitas panasnya. Algoritma juga dilengkapi dengan pencarian titik minimum global dari dua variable yaitu konduktivitas panas dan koefisien disipasi panas. Keunggulan dari perhitungan konduktivitas panas bahan ini mampu mengeliminir potensi masalah akibat kehilangan panas yang tidak teridentifikasi sehingga perhitungan menjadi lebih presisi. Keunggulan lainnya, prosedur pengukuran tidak membutuhkan eksperimen pendahuluan dalam rangka karakterisasi disipasi panas yang hilang ke lingkungan. Untuk pengukuran heat flux, eksperimen dilakukan dengan tingkat kesalahan pengukuran suhu ±0,5 ºC. Hasilnya menunjukkan korelasi yang baik antara fluks yang dihitung dan eksperimen. Deviasi maksimum fluks panas pengukuran adalah 7%. Pendekatan IHCP 2D juga telah diterapkan untuk mengukur konduktivitas panas bahan Titanium. Dengan ketelitian akusisi data temperatur ± 0.2 ºC, maka diperoleh deviasi maksimum hasil pengukuran konduktivitas panas sebesar 11.3% dari nilai sebenarnya 17,0 W/m.ºC. Ada kecenderungan semakin tinggi daya pemanas yang diterapkan, hasil pengukuran konduktivitas panas semakin presisi.

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Heat management is essential to ensure the continuity of industrial operations and to extend the service life of industrial installations. Various tools have been developed to characterize heat-related phenomena. This dissertation focuses on the development of methods for measuring heat flux from heat sources and the thermal conductivity of materials using a two-dimensional Inverse Heat Conduction Problem (IHCP) approach. The steady-state heat conduction problem in a 2D plate is modeled using the finite difference method. Based on temperature data obtained from experimental measurements, the heat flux and the thermal conductivity are determined by solving the inverse problem using the Conjugate Gradient Method (CGM). This measurement method requires both hardware and software. The hardware includes a thin copper plate and an instrumentation system to monitor the temperature distribution of the plate. The software is a MATLAB-based program developed to solve the IHCP. The advantages of this new method include the ability to measure heat flux over any surface area and from any type of heat source. For thermal conductivity measurements, the copper plate is replaced with a material specimen whose thermal conductivity is to be determined. The algorithm is also equipped with a global minimum search for two variables: thermal conductivity and heat dissipation coefficient. This method can eliminate potential errors due to unaccounted heat loss, resulting in inaccurate calculations. Another advantage is that the measurement procedure does not require preliminary experiments to characterize heat dissipation to the environment. For heat flux measurement, experiments were conducted with a temperature measurement error margin of ±0.5 ºC. The results show good correlation between calculated and experimental fluxes, with a maximum deviation of 7%. The 2D IHCP approach was also applied to measure the thermal conductivity of Titanium. With a temperature data acquisition accuracy of ±0.2 ºC, the maximum deviation in thermal conductivity measurement was 11.3% from the actual value of 17.0 W/m.ºC. There is a trend showing that the higher the applied heating power, the more accurate the thermal conductivity measurements become."