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In this study, closed-form solutions are presented to investigate thermohydraulics of liquid films in a rotating heat pipe. The film thickness is expressed as a function of flow rate.

Further, sensitivity of both film thickness and flow rate to the length of the rotating heat pipe can now be investigated using the explicit expressions presented here.

To make it easier for practical application, an approximate solution is presented on top of the exact solution.

Both approximate and exact solutions are then applied to note that results are in good agreement when compared to those available in the literature.

Impinging jets have been widely studied, and the addition of swirl has been found to be beneficial to heat transfer. As there is no literature on Reynolds-averaged Navier Stokes equations (RANS) nor experimental data of swirling jet flows generated by a rotating pipe, the purpose of this study is to fill such gap by providing results on the performance of this type of design.

As the flow has a different behaviour at different parts of the design, the same turbulent model cannot be used for the full domain. To overcome this complexity, the simulation is split into two coupled stages. This is an alternative to use the costly Reynold stress model (RSM) for the rotating pipe simulation and the SST k-ω model for the impingement.

The addition of swirl by means of a rotating pipe with a swirl intensity ranging from 0 up to 0.5 affects the velocity profiles, but has no remarkable effect on the spreading angle. The heat transfer is increased with respect to a non-swirling flow only at short nozzle-to-plate distances H/D < 6, where H is the distance and D is the diameter of the pipe. For the impinging zone, the highest average heat transfer is achieved at H/D = 5 with swirl intensity S = 0.5. This is the highest swirl studied in this work.

High-fidelity simulations or experimental analysis may provide reliable data for higher swirl intensities, which are not covered in this work.

This two-step approach and the data provided is of interest to other related investigations (e.g. using arrays of jets or other surfaces than flat plates).

This paper is the first of its kind RANS simulation of the heat transfer from a flat plate to a swirling impinging jet flow issuing from a rotating pipe. An extensive study of these computational fluid dynamics (CFD) simulations has been carried out with the emphasis of splitting the large domain into two parts to facilitate the use of different turbulent models and periodic boundary conditions for the flow confined in the pipe.

A direct numerical simulation with turbulent transport of a scalar quantity has been carried out to grasp and understand a laminarization phenomena caused by a pipe rotation. In this study, the Reynolds number, which is based on a bulk velocity and a pipe diameter, was set to be constant; Re_b=5283, and the rotating ratios of a wall velocity to a bulk velocity were set to be 0.5, 1.0, 2.0 and 3.0. A uniform heat‐flux was applied to the wall as a thermal boundary condition. Prandtl number of the working fluid was assumed to be 0.71. The number of computational grids used in this study was 256×128×128 in the z‐, r‐ and ϕ‐ directions, respectively. The turbulent quantities such as the mean flow, temperature fluctuations, turbulent stresses and pressure distribution and the turbulent statistics were obtained. Moreover, the Reynolds stress and the scalar flux budgets were also obtained for each rotating ratio. The turbulent drag decreases with the rotating ratio increase. The reason of this drag reduction can be considered that the additional rotational production terms appear in the azimuthal turbulence component. The contributions of convection and production terms to the radial scalar flux budget and also to the balance with temperature‐pressure gradient term are significant. The dissipation and viscous diffusion terms are negligible in higher rotating ratio.

The purpose of this paper is to examine the effect of application of a heat pipe in an aspect of hydrostatic thrust bearings on thermal balance and deformation and the role of this application in increasing the rotating speed of a workbench.

Numerical simulations of oil film temperature field, the temperature field and thermal deformation of the bearing’s workbench and base were performed by finite element analysis (FEA) software for both the traditional hydrostatic thrust bearings and the heat pipe ones.

Oil pad and workbench of the hydrostatic thrust bearings are fabricated with a heat pipe cooling structure, which can take away most of the heat generated by shearing of the oil film, control the temperature rise and thermal deformation of the hydrostatic thrust bearing effectively, avoid the dry friction phenomenon and finally improve the processing quality of equipment.

The heat pipe hydrostatic thrust bearings could control the temperature rise and thermal deformation of the hydrostatic thrust bearing effectively, avoid the dry friction phenomenon and improve the processing quality of equipment.

The purpose of this paper is to compile a comprehensive status report on pipes/piping networks across different industrial sectors, along with specifications of materials and sizes, and showcase welding avenues. It further extends to highlight the promising friction stir welding as a single solid-state pipe welding procedure. This paper will enable all piping, welding and friction stir welding stakeholders to identify scope for their engagement in a single window.

The paper is a review paper, and it is mainly structured around sections on materials, sizes and standards for pipes in different sectors and the current welding practice for joining pipe and pipe connections; on the process and principle of friction stir welding (FSW) for pipes; identification of main welding process parameters for the FSW of pipes; effects of process parameters; and a well-carved-out concluding summary.

A well-carved-out concluding summary of extracts from thoroughly studied research is presented in a structured way in which the avenues for the engagement of FSW are identified.

The implications of the research are far-reaching. The FSW is currently expanding very fast in the welding of flat surfaces and has evolved into a vast number of variants because of its advantages and versatility. The application of FSW is coming up late but catching up fast, and as a late starter, the outcomes of such a review paper may support stake holders to expand the application of this process from pipe welding to pipe manufacturing, cladding and other high-end applications. Because the process is inherently inclined towards automation, its throughput rate is high and it does not need any consumables, the ultimate benefit can be passed on to the industry in terms of financial gains.

To the best of the authors’ knowledge, this is the only review exclusively for the friction stir welding of pipes with a well-organized piping specification detailed about industrial sectors. The current pipe welding practice in each sector has been presented, and the avenues for engaging FSW have been highlighted. The FSW pipe process parameters are characteristically distinguished from the conventional FSW, and the effects of the process parameters have been presented. The summary is concise yet comprehensive and organized in a structured manner.

A numerical study is performed to investigate turbulent flow characteristics in a pipe rotating around the axis. Emphasis is placed on the effect of pipe rotation on the friction coefficient and velocity distribution in the hydrodynamically, fully‐developed flow region. The k—ε turbulence model is modified by taking the swirling effect into account, in which the model function including the Richardson number is introduced to the ε equation. The governing boundary‐layer equations are discretized by means of a control volume finite‐difference technique for numerical computation. Results obtained from the modified model agree well with experiment data in the existing literature. It is found from the study that (i) an axial rotation of the pipe induces an attenuation in the turbulent kinetic energy, resulting in a reduction in the friction coefficient, the turbulent and (ii) an increase in the velocity ratio causes substantial decreases in the friction coefficient, the turbulent kinetic energy and the streamwise velocity gradient near the wall.

A theoretical study is performed on three‐dimensional, heat transfer and fluid flow in radially rotating heated channels with steady, laminar throughflow. Consideration is given to the channel of different geometry. Both the rotational speed and throughflow rate are varied. The flow is hydrodynamically and thermally developing, with a constant wall heat flux. The velocity‐vorticity method is employed in the formulation and numerical results are obtained by means of a finite‐difference technique. The Nusselt number, friction factor, and temperature and velocity distributions are determined, and the role of the Coriolis force on the entrance‐region transport phenomena is investigated. Results are compared with the existing literature.

This article aims to study numerically three dimensional developing incompressible flow and heat transfer in a fixed curved pipe.

A projection algorithm based on the second order finite difference method is used for discretizing governing equations written in the toroidal coordinate system.

The effects of curvature and governing non‐dimensional parameters consisting of Reynolds, Prandtl, and Dean numbers on the flow field, entrance length, and heat transfer are studied in detail. The numerical results indicate that the entrance length depends only on the Reynolds number for the curvature ratios greater than 1/7 and therefore, Dean number is not a pertinent parameter in this range.

For heat transfer analysis, two different thermal boundary conditions, i.e. constant wall temperature and constant heat flux at the wall are implemented. The results are calculated for the Dean numbers in the range of 76‐522 and for the two prandtl numbers of 0.5 and 1.

The results can be used in designing heat exchangers, piping systems, and cooling of gas turbine blades.

The numerical results obtained here concentrate on the detailed investigation of flow and temperature field at the entrance region by a quantitative analysis of hydrodynamic and thermal entrance length. The effects of different thermal boundary conditions and different inlet profiles on the flow and temperature fields are studied in the circular curved pipe for the first time.

A method is presented for the determination of heat transfer rates in cylindrical cooling ducts which rotate about an axis orthogonal to its own axis of symmetry. The equations of motion and energy are solved in conjunction with the two equation model of turbulence (k—ε) using the finite element method. The importance of employing consistent velocity and turbulence quantities is demonstrated; the former condition is particularly relevant with respect to induced secondary flows. It was also found that comparatively minor mesh refinement had a significant effect on both the flow and the increase in heat transfer rates over those obtained for the non‐rotating case.