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Increasing the temperature of gas flows passing through hot tubes is one of the industrial interests. Operations in the gas phase with high temperature variations involve engineers with the compressible fluids problems. The paper aims to discuss this issue.

In this study, a mathematical three-dimensional turbulent model is applied for investigating the heat transfer and laminar gas flow inside the thermal developing zone of a hot tube. The Favre Averaged Navier–Stokes and energy equations and also the Reynolds Stress Model are numerically solved to obtain the fluid velocity and temperature profiles inside this the tube. This model is validated using the experimental data and also well-known formulas in this science.

Finally, effects of inlet volumetric flow rate, heating conditions of the tube wall and tube angle on the temperature and velocity distributions of the gaseous phase inside this zone are investigated.

The compressible laminar gas flow and also heat transfer in the thermal developing zone of a hot tube is studied using a three-dimensional turbulent model.

The purpose of this study is to provide a method for designing the shell and tube heat exchangers and examine the total annual cost of heat exchanger networks from the economic view based on the careful design of equipment.

Accurate evaluation of heat exchanger networks performance depends on detailed models of heat exchangers design. The simulations variables include nine design variables such as flow direction determination of each of the two fluids, number of tubes, number of tube passes, length of tubes, the arrangement of tubes, size and percentage of baffle cut, tube diameter and tube pitch. The optimal designing of the heat exchangers is based on geometrical and hydraulic modeling and using a hybrid genetic particle swarm optimization algorithm (PSO-GA) technique. In this paper, optimization and minimization of the total annual cost of heat exchanger networks are considered as the objective function.

In this study, a fast and reliable method is used to simulate, optimize design parameters and evaluate heat transfer enhancement. PSO-GA algorithms have been used to minimize the total annual cost, which includes investment costs of heat exchangers and pumps, operating costs (pumping) and energy costs for utilities. Three case studies of four, six and nine streams are selected to demonstrate the accuracy of the method. Reductions of 0.55%, 23.5% and 14.78% are obtained in total annual cost for the selected streams, respectively.

In the present study, a reliable method is used to simulate and optimize design parameters and the economic optimization of the heat exchanger networks. Taking into account the importance of shell and tube heat exchangers in industrial applications and the complexity in their geometry, the PSO-GA methodology is adopted to obtain an optimal geometric configuration. The total annual cost is chosen as the objective function. Applying this technique to case studies demonstrates its ability to accurately design heat exchangers to optimize the objective function of the heat exchanger networks by giving the detail of design.

This study aims to evaluate the melting process of the phase-change RT-35 material in a shell and tube heat exchanger saturated with a porous medium. Titanium porous media with isotropic and inhomogeneous structures are studied. The considered tubes in the shell and tube exchanger are made of copper with specific thicknesses. The phase-change material has a non-Newtonian behavior and follows the endorsed Carreau–Yasuda Model.

The enthalpy–porosity method is used for modeling of the melting process. The governing equations were transferred to their dimensionless forms. Finally, the equations are solved by applying the Galerkin finite element method.

The findings for different values of the relative permeability (K*) and permeability deviation angle (λ) are represented in the forms of charts, streamlines and constant temperature contours. The considerable effects of the relative permeability (K*) and deviation angle (λ) on the flow line patterns of the melting phase-change material are some of the significant achievements of this works.

This study was conducted using data from relevant research articles provided by reputable academic sources. The data included in this manuscript have not been published previously and are not under consideration by any other journal.

This paper seeks to describe automated lamp manufacturing.

The paper provides information on the automated manufacture of incandescent, fluorescent and light‐emitting diodes (LEDs).

The paper finds that the automated manufacture of conventional lamp types is similar, but LEDs require totally different techniques developed from the semiconductor industry.

The paper should be of value in terms of understanding the basics of automated lamp manufacturing, especially with LEDs, as these will be highly important general lighting products to save energy and provide innovation in lighting design in the near future.

The Secretary of State after consultation with the Engineering Industry Training Board and with organisations and associations of organisations appearing to be representative respectively of substantial numbers of employers engaging in the activities hereinafter mentioned and of substantial numbers of persons employed in those activities and with the bodies established for the purpose of carrying on under national ownership industries in which the said activities are carried on to a substantial extent and in exercise of his powers under section 9 of the Industrial Training Act 1964 and of all other powers enabling him in that behalf hereby makes the following Order:—

In the immediate post‐war years, school science apparatus was in short supply and the established manufacturers and supply houses provided very little in the way of new items. Criticism of the quality of available apparatus was frequently heard and was voiced in public at a particular A.G.M. of the Science Masters Association (now the ASE). This led in 1961 to a meeting (organised through the Scientific Instrument Manufacturers Association) between the principal manufacturers and a panel of HMIs. Whilst it was difficult for the latter to be specific about the shortcomings of apparatus on the market, it was suggested that SIMA should make contact with the then recently formed SMA Modern Physics Equipment Committee, which was concerning itself with the kind of new apparatus which would be required for teaching ‘modern physics’.

The Secretary of State after consultation with the Iron and Steel Industry Training Board and with organisations and associations of organisations appearing to be representative respectively of substantial numbers of employers engaging in the activities hereinafter mentioned and of substantial numbers of persons employed in those activities and with a body established for the purpose of carrying on under national ownership an industry in which the said activities are carried on to a substantial extent and in exercise of her powers under section 9 of the Industrial Training Act 1964(a) and of all other powers enabling her in that behalf hereby makes the following Order:—

The Minister of Labour after consultation with the Engineering Industry Training Board and with organisations and associations of organisations appearing to be representative respectively of substantial numbers of employers engaging in the activities hereinafter mentioned and of substantial numbers of persons employed in those activities and with the bodies established for the purpose of carrying on under national ownership industries in which the said activities are carried on to a substantial extent and by virtue of the powers conferred on him by section 9 of the Industrial Training Act 1964(a) and of all other powers enabling him in that behalf hereby makes the following Order:—

The effect of the tube wall heat conduction on the natural convection in a tilted long cylindrical envelope with constant, but different temperature of the two ends and an adiabatic outer surface was numerically investigated. The envelope is supposed to be a simplified model for the pulse tube in a pulse tube refrigerator when the pulse tube is positioned at different orientations. It is found that the cylindrical envelope lateral wall heat conduction can enhance the heat transfer from the hot end to the cold end, not only because of the increase in pure heat conduction in the wall, but more importantly, also the intensification of the natural convection within the enclosure. This enhancement is resulted from the big temperature difference between the tube wall and the adjacent fluid near the hot and cold ends. Adoption of low thermal conductivity tube can effectively reduce such additional heat transfers from hot to cold end, thus reducing the loss of cooling capacity for the pulse tube refrigerator.

Heat exchangers (HEs) which provide heat transfer and transfer energy through direct or indirect contact between fluids have an essential role in many processes as a part of various industries from pharmaceutical production to electronic devices. Using nanofluid as working fluid and integrating different types of turbulators could be used to upgrade the thermal effectiveness of HEs. Recently, to obtain more increment in thermal effectiveness, hybrid nanofluids are used that are prepared by mixing two or more various nanoparticles. The purpose of this experimental and numerical study is investigating different scenarios for improving the effectiveness of a concentric U-tube type HE.

In the numerical section of this study, different turbulator modifications, including circular and quarter circular rings, were modeled to determine the effect of adding turbulator on thermal performance. In addition, Al₂O₃/water and SiO₂/water single and Al₂O₃–SiO₂/water hybrid nanofluids were experimentally tested in an unmodified concentric U-tube HE in two different modes, including counter flow and parallel flow. Al₂O₃–SiO₂/water hybrid nanofluid was prepared at 2% (wt./wt.) particle ratio and compared with Al₂O₃/water and SiO₂/water single type nanofluids at same particle ratios and with distilled water.

Numerical modeling findings exhibited that integrating turbulators to the concentric tube type HE caused to raise in the effectiveness by improving heat transfer area. Also, experimental results indicated that using both hybrid and single type nanofluids notably upgraded the thermal performance of the concentric U-tube HE. Integrating turbulators cannot be an effective alternative in a concentric U-tube type HE with lower diameter because of raise in pressure drop. Numerically achieved findings exhibited that using quarter circular turbulators decreased pressure drop in comparison with circular turbulators. According to the experimental outcomes, using hybrid Al₂O₃–SiO₂/water nanofluid leads to obtain more thermal performance in comparison with single type nanofluids. The highest increment in overall heat transfer coefficient of HE by using Al₂O₃–SiO₂/water nanofluid achieved as 58.97% experimentally.

The overall outcomes of the current research exhibited the positive impacts of using hybrid nanofluid and integrating turbulators. In this empirical and numerical survey, numerical simulations were performed to specify the impact of applying different turbulators and hybrid nanofluid on the flow and thermal characteristics in a concentric U-tube HE. The achieved outcomes exhibited that using hybrid nanofluid can notably increase the thermal performance with negligible pressure drop in comparison with two different turbulator modifications.