Abstract With the development of computer processors, the size of chip has become smaller. But the processors used in high-power needs high performance of heat dissipation. In electronic design of the thermal management, the heat sink is the most basic application. Since the natural convection can not cool down effectively, it needs to use the forced convection cooling. The purpose of this study explored water-cooled sink as the heat source for the high-power chip. The study findings show that the ATC cooling chip enhances the potency and decreased the noise. Most importantly, it dissipates heat. In the present study, the researcher used Computational Fluid Dynamics to analyze the heat flow problem. By applying three variables in terms of the flow channel, the housing size, and the heat sink size in data analyses, the researcher classified different types of water-cooled sink. From the discussion of different flow rate and the thermal resistance, it shows that the trend curve of the fin-gilled sink is different from others. It also shows that it performs better in the low flow rate. After all using each method of heat dissipation, the potency of N-type channel sink is the best. When flow rate is 2.2 L/min, the thermal resistance is 0.0971˚C/W.

Thesis (M.S.)--University of Michigan, 1958.

Thesis (M.S.)--University of Michigan, 1971. / eContent provider-neutral record in process. Description based on print version record.

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 81-82).

Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 159-163).

Measurements of mean velocity and mean temperature fields and wall parameters for air flowing in a smooth, vertical tube at low entry Reynolds numbers are presented for heating with constant wall heat flux along the heated length. Two entry Reynolds numbers of approximately 6000 and 4000 were employed with three heating rates, q('+) = q('w'')/ (Gc(,p,i) T(,i)), of approximately 0.0018, 0.0035 and 0.0045. The flow development was measured by obtaining internal profiles along the heated length at axial locations from x/D = 3.17 to x/D = 24.54. An adiabatic entry of 50 diameters preceded the heated region. The three heating rates caused slight, large and severe property variation of the air. The highest heating rate was found to cause significant buoyancy effects. The internal measurements were obtained using constant temperature hot-wire anemometry and resistance thermometry for velocity and temperature, respectively, employing a single short wire probe. The technique developed and employed for the use of a single short hot wire in velocity measurements in non-isothermal flows is presented. The measurements are compared to numerical predictions employing two simple versions of the van Driest mixing length turbulence model. In general, both models agreed with the measurements reasonably well, but for the higher heating rates neither model was completely satisfactory in predicting the velocity profiles. When the buoyancy parameter reached 0.3, the peak velocity occurred in the wall region rather than at the tube centerline. Typically, the Nusselt number was overpredicted by 10% for x/D > 14 and, consequently, the wall temperature was underpredicted by about 7%.

No description available.

No description available.

High-temperature gas-cooled reactors (HTGR) are passively safe, efficient, and economical solutions to the world’s energy crisis. HTGRs are capable of generating high temperatures during normal operation, introducing design challenges related to material selection and reactor safety. Understanding heat transfer and fluid flow phenomena during normal and transient operation of HTGRs is essential to ensure the adequacy of safety features, such as the reactor cavity cooling system (RCCS). Modeling abilities of system analysis codes, used to develop an understanding of light water reactor phenomenology, need to be proven for HTGRs. RELAP5-3D v2.3.6 is used to generate two reactor plant models for a code-to-code and a code-to-experiment benchmark problem. The code-to-code benchmark problem models the Russian VGM reactor for pressurized and depressurized pressure vessel conditions. Temperature profiles corresponding to each condition are assigned to the pressure vessel heat structure. Experiment objectives are to calculate total thermal energy transferred to the RCCS for both cases. Qualitatively, RELAP5-3D’s predictions agree closely with those of other system codes such as MORECA and Thermix. RELAP5-3D predicts that 80% of thermal energy transferred to the RCCS is radiant. Quantitatively, RELAP5-3D computes slightly higher radiant and convective heat transfer rates than other system analysis codes. Differences in convective heat transfer rate arise from the type and usage of convection models. Differences in radiant heat transfer stem from the calculation of radiation shape factors, also known as view or configuration factors. A MATLAB script employs a set of radiation shape factor correlations and applies them to the RELAP5-3D model. This same script is used to generate radiation shape factors for the code-toexperiment benchmark problem, which uses the Japanese HTTR reactor to determine temperature along the outside of the pressure vessel. Despite lacking information on material properties, emissivities, and initial conditions, RELAP5-3D temperature trend predictions closely match those of other system codes. Compared to experimental measurements, however, RELAP5-3D cannot capture fluid behavior above the pressure vessel. While qualitatively agreeing over the pressure vessel body, RELAP5-3D predictions diverge from experimental measurements elsewhere. This difference reflects the limitations of using a system analysis code where computational fluid dynamics codes are better suited.

Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on January 12, 2010. Major professor: Patrick Lemieux, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Mechanical Engineering." "December 2009." Includes bibliographical references (p. 46).