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The purpose of this study is to promote laminar heat transfer from the channel heated through a slab with slits and inclined ribs protruding across.

The novel design of this study is performed through making the slits in the slab (C1–C3: with slits; C4–C6: without slits) and changing the vertical location of this slab (1/4, 1/2 and 3/4 channel height). The thermal fluid characteristics of all cases are analyzed for various Reynolds numbers (500, 1,000, 1,500 and 2,000) by the SIMPLE-C algorithm.

The results display that the ribbed slab effectively improves the heat transfer. The slits can modify the flow field in the vortexes around the inclined ribs and remove more heat from this zone to promote the heat transfer. As compared with C0 (without a slab), C2 (the slab with slits and inclined ribs protruding across located vertically on the 3/4 channel height) raises the averaged Nusselt number up to 27.7% at Re = 2,000. As compared with C4 (without slits), C1 (with slits) gains the maximum increase in the averaged Nusselt number by 5.07% at Re = 1,000.

The constant thermo-physical properties of incompressible fluid and the steady flow are considered in this study.

The numerical results will profit the design of heated passageway using a slab with slits and inclined ribs protruding across to acquire better heat transfer promotion.

This slab with slits and inclined ribs protruding across can be applied to the heat transfer promotion and thus be viewed as a useful cooling mechanism in the thermal engineering.

The purpose of this study is to advance turbulent thermal convection inside the constant heat-flux round tube inserted by multiple perforated twisted tapes.

The novel design of this study is accomplished by inserting several twisted tapes and drilling some circular perforations near the tape edge (C1, C3, C5: solid tapes; C2, C4, C6: perforated tapes). The turbulence flow appearances and thermal convective features are examined for various Reynolds numbers (8,000–14,000) using the renormalization group (RNG) κ−ε turbulent model and Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm.

The simulated outcomes reveal that inserting more perforated-twisted tapes into the heated round tube promotes turbulent thermal convection effectively. A swirling flow caused by the twisted tapes to produce the secondary flow jets between two reverse-spin tapes can combine with the main flow passing through the perforations at the outer edge to enhance the vortex flow. The primary factors are the quantity of twisted tapes and with/without perforations, as the perforation ratio remains at 2.5 in this numerical work. Weighing friction along the tube, C6 (four reverse-spin perforated-twisted tapes) brings the uppermost thermal-hydraulic performance of 1.23 under Re = 8,000.

The constant thermo-hydraulic attributes of liquid water and the steady Newtonian fluid are research limitations for this simulated work.

The simulated outcomes will avail the inner-pipe design of a heat exchanger inserted by multiple perforated twisted tapes to enhance superior heat transfer.

These twisted tapes form tiny circular perforations along the tape edge to introduce the fluid flow through these bores and combine with the secondary flow induced between two reverse-spin tapes. This scheme enhances the swirling flow, turbulence intensity and fluid mixing to advance thermal convection since larger perforations cannot produce large jet velocity or the position of perforations is too far from the tape edge to generate a separated flow. Consequently, this work contributes a valuable cooling mechanism toward thermal engineering.

EACH September the eyes of the aeronautical World turn towards the S.B.A.C. Air Display and Exhibition with interest unequalled by any other event. It is fitting that the Display is now held each year at the airfield of the Royal Aircraft Establishment, one of the world's most prominent aeronautical research centres. This interest becomes increasingly keen too, as the preview day comes closer, because new prototypes of unorthodox designs often appear a short time before the Show to illustrate the results of years of careful planning, development and research of the particular company. These designs often mould the path of progress for smaller countries without the economic resources to forge the way ahead alone. Most British citizens are very proud of their country's place in aviation today, both in the military and civil fields. This is understood by most foreigners because it is clear that Britain has won a place in aeronautical development second to none.

This paper aims to predict turbulent flow and heat transfer through different channels with periodic dimple/protrusion walls. More specifically, the performance of various low-Re k-ε turbulence models in prediction of local heat transfer coefficient is evaluated.

Three low-Re number k-ε turbulence models (the zonal k-ε, the linear k-ε and the nonlinear k-ε) are used. Computations are performed for three geometries, namely, a channel with a single dimpled wall, a channel with double dimpled walls and a channel with a single dimple/protrusion wall. The predictions are obtained using an in house finite volume code.

The numerical predictions indicate that the nonlinear k-ε model predicts a larger recirculation bubble inside the dimple with stronger impingement and upwash flow than the zonal and linear k-ε models. The heat transfer results show that the zonal k-ε model returns weak thermal predictions in all test cases in comparison to other turbulence models. Use of the linear k-ε model leads to improvement in heat transfer predictions inside the dimples and their back rim. However, the most accurate thermal predictions are obtained via the nonlinear k-ε model. As expected, the replacement of the algebraic length-scale correction term with the differential version improves the heat transfer predictions of both linear and nonlinear k-ε models.

The most reliable turbulence model of the current study (i.e. nonlinear k-ε model) may be used for design and optimization of various thermal systems using dimples for heat transfer enhancement (e.g. heat exchangers and internal cooling system of gas turbine blades).

Orbital forming is an efficient and precise process to assemble component parts. It provides strength, an attractive finished appearance, and batch‐to‐batch uniformity. Orbital forming machines can produce high‐torque assemblies and also freely swinging joints, and any degree of built‐in resistance in between. These machines quietly flare and form all malleable materials, including many engineering thermoplastics, and work safely on delicate and brittle parts. The machine controls provide infinitely variable cycle times (speed), forming pressure and tool stroke on the micrometer dial with resolution to 0.001 in.

SEVERAL new types of commercial aeroplane have appeared in France recently, to meet modern requirements on the various air lines. All these machines are multi‐engined monoplanes, mostly with pure cantilever planes of metal construction. The designers have aimed at higher speed and improved life in service, while the comfort for passengers has made substantial progress.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued.

THE Bréguet 410 multiplace de combat is a twin‐engine sesquiplane recently completed by this firm. It is the latest of a series of all‐metal military types of which the Bréguet 27, known as the “Tout Acier” (described in AIRCRAFT ENGINEERING, Vol. I, July, 1929, p. 181, and Vol. II, September, 1930, pp. 219–222) was the prototype. Among the features in the 410 derived from preceding developments of this type of Bréguet design are the beam fuselage, the undercarriage, the incidence adjustment of the top wing and the single‐unit construction of the lower wing built up round a girder.

IT is a long time since The Life of Johnson defined man as a tool‐making animal, and the tools he used in those days were primitive when contrasted with the precise, complicated and sophisticated ones employed today. Early tools were really evolved through centuries as necessary extensions of a man's arms. A spade gave them leverage and a longer reach.