Investigation of heat transfer augmentation through use of internally finned and roughened tubes : final summary report

This report summarizes a three-year program concerned with obtaining basic design information for tubes having a random roughness on the inside wall (RID) and tubing having continuous internal fins (Forge Fin). Test apparatus and procedures were developed to obtain accurate heat-transfer and friction data for a wide variety of tube geometries using water as the test fluid. For the random roughness the heat-transfer coefficient was above the smooth tube value, for comparable flow conditions, by over 60 percent at a Reynolds number of 30,000. Larger percentage improvements can be expected for higher Reynolds numbers and for fluids having higher Prandtl numbers. Improvements in performance, based on equal pumping power for augmented and smooth tubes, of about 50 percent were observed. The heat-transfer characteristics for tape-generated swirl flow through rough tubes were investigated in order to determine the interaction of swirl flow and roughness effects. For the particular range of parameters covered, for equal flow rates, the maximum improvement in heat transfer with swirl flow in smooth tubes was 70 percent, whereas with swirl flow in rough tubes, the improvement was as much as 100 percent. The heat-transfer coefficient for rough tube swirl flow was accurately correlated by a modification of an additive expression previously suggested for prediction of smooth tube swirl flow data.(cont.) The test program for internally finned tubes established that short spiralled fins produce the greatest improvement in heat transfer. On the basis of equal flow conditions, the heat transfer was improved by over 200 percent; while at equal pumping power, the performance was as high as 170 percent. These improvements, which are attributed to increased area and turbulence promotion, appear to equal the improvements displayed by any of the schemes used to augment heat transfer inside tubes. In order to bring the augmentation problem into perspective, a discussion of data for other types of roughness and finning is included.DS

Investigation of heat transfer augmentation through use of internally finned tubes

This thesis document was issued under the authority of another institution, not NPS. At the time it was written, a copy was added to the NPS Library collection for reasons not now known.  It has been included in the digital archive for its historical value to NPS.  Not believed to be a CIVINS (Civilian Institutions) title.http://www.archive.org/details/investigationofh00snidLieutenant, United States Coast Guar

Tevatron Run II combination of the effective leptonic electroweak mixing angle

International audienceDrell-Yan lepton pairs produced in the process pp¯→ℓ+ℓ-+X through an intermediate γ*/Z boson have an asymmetry in their angular distribution related to the spontaneous symmetry breaking of the electroweak force and the associated mixing of its neutral gauge bosons. The CDF and D0 experiments have measured the effective-leptonic electroweak mixing parameter sin2θefflept using electron and muon pairs selected from the full Tevatron proton-antiproton data sets collected in 2001-2011, corresponding to 9–10  fb-1 of integrated luminosity. The combination of these measurements yields the most precise result from hadron colliders, sin2θefflept=0.23148±0.00033. This result is consistent with, and approaches in precision, the best measurements from electron-positron colliders. The standard model inference of the on-shell electroweak mixing parameter sin2θW, or equivalently the W-boson mass MW, using the zfitter software package yields sin2θW=0.22324±0.00033 or equivalently, MW=80.367±0.017  GeV/c2