The potential industrial applications of curved tubes for single- and two-phase flow are reviewed within the context of physics of flow, trends in the development of technology, and its laboratory to industrial-scale commercialization. Comparison of the performance of curved tube configurations demonstrates its edge over the conventional motionless mixers, heat exchangers, and reactors. Alongside, their respective advantages and limitations are also highlighted. Further, a compendium of the available correlations for single- and two-phase friction factor and heat- and mass-transfer coefficient in curved tubes has also been presented. Key issues regarding the design parameters governing the performance of the curved tubes for mixing and heat- and mass-transfer that impact the research, development, and scale-up or scale-down of such devices are also analyzed. Emerging trends for the development of a new class of curved tubes, namely, inverters and serpentine and chaotic devices are also presented.

A Review on the Potential Applications of Curved Geometries in Process Industry

A calculation procedure for three-dimensional parabolic flows is applied to predict the velocity and temperature fields in helically coiled pipes. The curvature produces a secondary flow and causes departures from the symmetric velocity profile of Poiseuille flow. Predictions are presented of flow and heat transfer in the developing and fully developed regions. Comparisons of the developing and fully developed velocity profiles with experimental data exhibit good agreement. The development of the wall temperature for the case of axially uniform heat flux with an isothermal periphery has been compared with experimental data and the agreement is good. Predictions for fully developed temperature profiles and heat-transfer coefficients also exhibit good agreement with experimental data. Effects of the Dean number on the friction factor and heat transfer are presented.

Prediction of laminar flow and heat transfer in helically coiled pipes

The currency of the research consists in the necessity if rethinking of the notion of culture in Russian contemporary thought in order to present more adequately the process of development of culture in a future. The paper aims to elucidate political origins of the movement of Proletarian culture that play the leading role in a creation of a new conception of culture. As a materials were used documents and archives, scientific paper of Russian and foreign researchers. As a maim method was used problematicanalytical reconstruction, explored in the framework of an enactive approach that allows to envelop the subject in its evolvement and to concentrate on concrete practical situations of its realization. Such reconstruction permits to accomplish the original interpretation of the problem. The authors focus in the pre-history of the movement. Analyzing the social-political context of the origin of the movement, the authors come to the conclusion about artificially created necessity of political enlightenment of the society by the revolutionaries. The paper demonstrates how agents of proletarian working circles manipulate by the public opinion of working class. As a result, the paper shows the process of formation the ideology of cultural movement revolutionary period and evaluates significance of ideological function in its realization. The authors produce critical evaluation of the history of the movement in original judgment about political grounding of culture.

Индикаторы качества светодиодных осветительных систем, применяемых в стоматологической практике для местного освещения операционного поля

Pressure drop and convective heat transfer of water and nanofluids in a double-pipe helical heat exchanger

Solutions for steady, fully developed, laminar flow of an incompressible Newtonian fluid through a helically coiled tube of finite pitch were obtained by finite difference calculations. Prior theoretical solutions have apparently been limited to toroidal flow (with zero pitch). The computed results are consistent with those for this limiting case and with prior experimental data for finite pitch. The behavior for helical coils is intermediate between that for a straight pipe and a torus, and, for a moderate degree of pitch differs only slightly from that for a torus. A correlating equation was developed for the friction factor for all Reynolds numbers, all ratios of coil radius to lube radius and all ratios of pitch to coil radius for which the flow remains laminar.

Fully developed laminar flow in a helically coiled tube of finite pitch

Steady laminar flow in a curved pipe of circular cross section is investigated. It is assumed that the flow consists of a frictionless central core surrounded by a boundary layer. A formula for the friction factor of a curved pipe is derived, and the discharge coefficient for a 360-deg elbow flowmeter is discussed.



Die stationare laminare Stromung in einem gekrummten Rohr von kreisformigem Querschnitt wird untersucht. Es wird angenommen, das man das Stromungsfeld eine reibungslose Kernstromung und eine wandnahe Grenzschicht aufteilen kann. Man erhalt eine Widerstandsformel fur das gekrummte Rohr. Auserdem wird die Durchfluszahl eines als Mengenmesinstrument verwendeten 360°-Krummers behandelt.

H. Itō

Papers

Laminar Flow in Curved Pipes