Thermal performance of spiral inserts in a heat exchanger using hybrid nanofluids

Hydrothermal behaviour of hybrid nanofluid flow in a shell-and conical coil tube heat exchanger; numerical approach

A system dynamics model for analyzing energy consumption and CO2 emission in Iranian cement industry under various production and export scenarios

The Impact of Improvement in Iran Iron and Steel Production Technology on Environment Pollution

Purpose 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. Design/methodology/approach 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. Findings 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. Originality/value 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.

In the present study, the effect of inserting an innovative curved turbulator and utilizing two types of hybrid nanofluids on thermal performance in a helical double-pipe heat exchanger is evaluated numerically. The considered hybrid nanofluids include silver (Ag) and graphene (HEG) nanoparticles/water and multi-wall carbon nanotubes–iron oxide nanoparticles/water (MWCNT-Fe3O4/water). The considered innovative turbulator has 12 blades to create secondary flows. Also, a hole is considered at the end of the turbulator. The present study has two sections: In the first one, the results of utilizing hybrid nanofluids are compared with pure water (φ = 0.3%). In the second section, the hybrid nanofluid based on the first section was selected and utilized. The effect of the volume concentration of the selected hybrid nanofluid was investigated. Results show that utilizing the present innovative turbulator leads to higher heat transfer rate. As a result, the Ag-HEG/water hybrid nanofluid has better thermal performance at low mass flow rate. Also, the thermal efficiency of the considered helical heat exchanger is lowest at φ = 0.1%. In the case of highest volume concentration (φ = 0.7%), the thermal performance is maximum at low mass flow rate.

Experimental investigation on the thermal performance of a coiled heat exchanger using a new hybrid nanofluid

In the present work, hybrid nanofluids flow and heat transfer in a pipe equipped with vortex generator are evaluated numerically. At the first part, the impact of the type of working fluid (two various hybrid nanofluids in comparison with pure water at φ = 3%) and at the second part, impact of the volume concentration of selected hybrid nanofluid (based on section one) on the turbulence thermal performance of the pipe with innovative vortex generator are evaluated numerically. All the simulations were performed for the Reynolds number range between 4125 and 5363. The considered hybrid nanofluids include silver (Ag) and graphene (HEG) nanoparticles/water and MWCNT–Fe3O4/water. The proposed vortex generator has 18 blades to create secondary flows. Also, five output ports are considered at the conical part of vortex generator (four side outputs and one axial one). Results indicated that using both two techniques of heat transfer enhancement in a pipe including proposed vortex generator and hybrid nanofluids leads to higher heat transfer rate. As a result, the MWCNT–Fe3O4/water hybrid nanofluid has better thermal performance in all studied Reynolds number. At low Reynolds number (Re = 4125), the maximum thermal performance was achieved at φ = 1% by 11.3% growth in thermal performance. Also, case with φ = 5% has a minimum improvement, 10.5%. Furthermore, at high Reynolds number (Re = 5363), the highest and lowest growths belong to cases φ = 3% and φ = 7% by 9.9 and 7% improvement in thermal performance, respectively.

One of the priorities of modern industrial production is the optimization of heat energy consumption. The use of different technical solutions can reduce the heat energy consumption in industry and energetics. The paper considers how the optimization of heat energy consumption is influenced by the following technical solutions: increasing the efficiency of the boiler, returning the condensate to steam boilers and using the evaporator, setting the process parameters of combustion in industrial furnaces, heat insulation of the reservoirs, vessels and installations, application of heat pumps and the use of renewable energy sources and waste materials. Each of the considered technical solutions leads to a reduction in the consumption of heat energy and emissions of waste gases into the atmosphere.

PurposeThis study aims to examine double-diffusive natural convection (DDNC) in a swastika-shaped porous cavity filled with a hybrid nanofluid (Fe3O4-GO/water). It aims to analyze heat and mass transfer under varying thermophysical properties and key parameters like Rayleigh (Ra), Darcy (Da), Lewis (Le), Schmidt (Sc) numbers and buoyancy ratio (N). The research seeks to evaluate the hybrid nanofluid’s performance compared to mono nanofluids, providing insights for applications in cooling systems, heat exchangers and chemical processing. The study addresses the gap in understanding hybrid nanofluid behavior in complex porous geometries under combined thermal and solutal buoyancy effects.Design/methodology/approachThe coupled partial differential equations for mass, momentum, energy and species concentration are solved using a stable, higher-order finite element method (FEM). Temperature- and concentration-dependent thermophysical properties of the hybrid nanofluid are incorporated. The FEM code is validated against experimental data and numerical benchmarks. The important parameters are systematically varied to assess their impact on heat and mass transfer. Performance metrics such as average Nusselt number (Nuavg), Sherwood number (Shavg) numbers and kinetic energy (KEavg) are analyzed to compare hybrid and mono nanofluids under different porous media conditions.FindingsIncreasing buoyancy ratio (N) from 0–4 enhances Nuavg (8.30%–8.36%), Shavg (14.61%–15.01%) and KEavg, highlighting solutal buoyancy’s strong influence. Higher Ra transitions the system from conduction- to convection-dominated regimes, with Nuavg rising by 50.89% and Shavg by 65.20% at Ra = 106 as Da increases (10–5–10–2). The hybrid nanofluid outperforms mono nanofluids, with Nuavg increasing by 0.28%–1.46% and Shavg by 0.08%–0.40% as nanoparticle volume fraction (?) rises (0.01–0.05). These results demonstrate the hybrid nanofluid’s superior thermal and solutal transport capabilities in porous media.Originality/valueThis study presents novel insights into DDNC of hybrid nanofluids in a uniquely shaped porous cavity, addressing a gap in existing literature. The temperature- and concentration-dependent modeling of hybrid nanofluid properties enhances accuracy. The validated FEM approach ensures reliability for complex geometries. Findings reveal significant improvements in heat and mass transfer due to hybrid nanoparticles, offering practical benefits for industrial applications like advanced cooling and chemical processing. The quantitative analysis of key parameters provides a benchmark for future studies, emphasizing the hybrid nanofluid’s potential to outperform conventional fluids in porous media systems.

Energy consumption worldwide has increased significantly over the past few decades due to increasing population and economic growth. Efficient building energy consumption prediction plays an important role in energy planning, management, and conservation in smart buildings. This paper presents a new machine learning (ML) approach for the prediction of energy consumption in industrial buildings. It presents a trade-off between the performance and the interpretability of ML models which are major issues for building energy prediction using ML. The applicability of the proposed approach is demonstrated by a real case study to predict energy consumption in the steel industry. It shows that the Random Forest (RF) model provides the most effective prediction results, and the permutation feature importance helps the steel industry experts to better understand the judgments of the model. Hence, it will assist them to optimize energy consumption and make the most appropriate decision in industrial buildings.

Hydrothermal analysis of hybrid nanofluid flow inside a shell and double coil heat exchanger; Numerical examination

Process parameter analysis plays a vital role in today's modern world in all industries. The demand for energy consumption in industries has made designers build efficient heat exchangers. One of the most used heat exchangers is the shell and tube heat exchanger. This work is based on analyzing velocity profile, temperature, and pressure in shell and tube heat exchangers. Thermal analysis and flow analysis is considered as basic method to be performed along with some basic structural analysis by means of individual analysis of heat transfer components. The simulation also provides insights into the flow behavior and temperature distribution in the heat exchanger, which can be used for optimizing the design and operation of the device. Results based on those analyses are collected and experimented to get the required output values. In this study, we utilize COMSOL Multiphysics, a powerful computational tool for simulating heat transfer phenomena, to model and analyze the performance of a shell and tube heat exchanger. In this process, we use water - ethylene glycol system and an air- glycol system as a component in the shell and tube side. Across industries and disciplines, simulation modeling provides valuable solutions by giving clear insights into complex systems. The main objective of this study is to investigate the thermal performance of the heat exchanger by simulating the fluid flow and heat transfer processes inside the tubes and the shell. Keywords: shell and tube heat exchanger, analysis, thermal performance, comsol software.

Augmentation of heat exchanger performance with hybrid nanofluids: Identifying research gaps and future indications - A review

The optimization of heat transfer in heat exchanging equipment is paramount for the efficient management of energy resources in both industrial and residential settings. In pursuit of this goal, this empirical study embarked on enhancing the heat transfer performance of a double pipe heat exchanger (DPHX) by introducing silver (Ag)-graphene oxide (GO) hybrid nanofluids into the annulus of the heat exchanger. To achieve this, three distinct molar concentrations of Ag ornamented GO hybrid nanoparticles were synthesized by blending GO nanoparticles with silver nitrate at molarities of 0.03 M, 0.06 M, and 0.09 M. These Ag-GO hybrid nanoparticles were then dispersed in the base fluid, resulting in the formation of three distinct hybrid nanofluids, each with a consistent weight percentage of 0.05 wt%. Thorough characterization and evaluation of thermophysical properties were performed on the resulting hybrid nanomaterials and nanofluids, respectively. Remarkably, the most significant enhancement in heat transfer coefficient, Nusselt number, and thermal performance index (62.9%, 33.55%, and 1.29, respectively) was observed with the 0.09 M Ag-GO hybrid nanofluid, operating at a Reynolds number of 1,451 and a flow rate of 47 g/s. These findings highlight the substantial improvement in thermophysical properties of the base fluid and the intensification of heat transfer in the DPHX with increasing Ag molarity over GO. In summary, this study emphasizes the vital importance of optimizing the molarity of the material, which also plays a significant role in nanoparticle synthesis to achieve the optimal amplification of heat transfer.

Energy consumption and industry value-added are crucial to economic activities and have been a potential priority for China’s domestic economic growth, especially in the resource-rich central region of the Country. The research examines the impact of energy consumption and industry value- added on economic growth in six central Chinese areas from 2000 to 2022. The study employed the PMG estimator during data estimation, along with Quantile and FMOLS regressions for robustness checks. The research utilized disaggregated data on industrial value added, specifically primary, secondary, and tertiary industry value added. The findings indicated that higher energy consumption in primary and tertiary industries significantly stimulates economic growth, while the secondary industry value-added is not significant. Furthermore, capital accumulation and urbanization significantly contributed to economic growth. The labor force indicated a negative effect on growth, possibly due to inefficiencies, low productivity, or structural imbalances in the economy. The research recommended that policymakers ought to consider different patterns of energy consumption in industrial value-added firms for greater economic growth. There is a need for labor market reforms and productivity-boosting policies. Policymakers need to consider the unique economic and energy consumption patterns of Central China when designing and implementing energy policies. A one- size-fits-all approach is ineffective due to regional disparities.