Heat exchangers are widely recognized as eco-friendly devices that transfer heat between two or more fluids without mixing. Double Pipe Heat Exchangers (DPHE) are used in many industrial applications such as power generation, chemical processing, HVAC, and renewable energy systems. Traditional DPHEs are simple and reliable, however, they often face limitations in heat transfer. Improving the thermal performance of DPHE can significantly enhance the operational efficiency of thermal energy systems. This study presents a novel fin arrangement to the traditional DPHE using different diamond-shaped fins to improve its thermal performance. The thermal and hydraulic properties of DPHE with different diamond-shaped fin configurations are investigated using CFD analysis. The optimization process is carried out using the Response Surface Method (RSM) for optimal diamond-shaped fin design. The results indicate that novel diamond-shaped fins improve thermal performance, particularly at high mass flow rates. The thermal enhancement factor (TEF), overall heat transfer coefficient, and pressure drop are used to evaluate the thermal performance of DPHE. The diamond-shaped fins exhibit a 55% increase in overall heat transfer coefficient compared to conventional DPHE. The TEF for diamond-shaped fin configurations is higher than 1 with a maximum value of 1.63 for DPHE-HF45 depicting a 63% increase in thermal enhancement. The optimization results show that the optimal fin design achieves a desirability of 81.3%, with a pressure drop of 870.726 Pa and an overall heat transfer coefficient of 2199.85 W/m 2 K at a mass flow rate of 2.711 lit/min.

Polymer encapsulation of Cynara Scolymus L. extract using supercritical fluid expansion into an aqueous solution (ESSAS): Optimization of conditions, identification of compounds using LC-HRMS, and investigation of antioxidant properties.

Double filament feed spacers for enhanced performance in reverse osmosis modules.

Optimisation of a cut-tube absorber for parabolic trough collectors to minimise heat loss and pressure drop

The impacts of gas-liquid two-phase flow regimes on heat transfer performance and pressure drop in microchannels-an experimental study

Dynamic correlation mechanisms of water distribution and pressure drop in PEMFCs based on optical visualization technology

Effectiveness of fractional flow reserve and resting full-cycle ratio in arteries with tandem stenosis.

Experiments and modeling of pressure drop for the droplet flow system in a tubular packed bed

Study on solidification behaviors and pressure drop characteristics of molten salt in filling cold pipe

A mechanistic predictive model for pressure drop and void fraction calculation in two-phase flows and annular flow regime

Numerical and experimental studies on the pressure drop of hydrogen-blended methane pipelines

The development of a model with a macro characteristic element for predicting pressure drop across the particle bed

Air pollution has emerged as one of the most pressing environmental challenges, primarily driven by rapid industrialization and climate-related phenomena. Within this context, nanofiber-based filter materials offering high particle capture efficiency and low pressure drop (ΔP) play a crucial role in ensuring access to clean air. In this study, nanofibrous filter surfaces based on thermoplastic polyurethane (TPU) were fabricated via the melt-blowing (MB) technique a solvent-free and high-throughput production method. The experimental design was structured using a Taguchi L9 orthogonal array, considering three processing parameters at three levels each: feeding rate (1, 5, and 10 rpm), die (nozzle) temperature (220, 240, and 260 °C), and air pressure (1, 2, and 3 bar). The morphological characteristics of the produced nanofibers were examined through scanning electron microscopy (SEM). Their AFDs, filtration efficiencies, pressure drops (ΔP), air permeabilities, and quality factors (QFs) were systematically compared. The sample produced under the optimal conditions -1 rpm feeding rate, 260 °C die temperature, and 3 bar air pressure- demonstrated the best performance, achieving a filtration efficiency of 82.12% and a ΔP of 95 Pa, with an average fiber diameter (AFD) of 423 ± 47 nm. Moreover, this optimal sample was subjected to mechanical strain levels of 5%, 10%, and 20%, and successfully preserved its functional integrity, maintaining a filtration efficiency of 71.44% even at 20% elongation. These findings highlight the potential of the melt-blown process as an environmentally friendly, rapid, scalable, and solvent-free method to produce high-performance TPU based nanofibrous air filters.

Continuous manifold systems (CMS) are widely used for energy and mass transfer. The flow distribution of the branch ports directly affects the flow pattern of the chamber. However, the current understanding of the flow distribution in CMS under unsteady flow conditions and the optimization of their geometry is still limited. In this study, three-dimensional numerical simulations were performed to investigate the flow distribution of branch ports under unsteady flow conditions. Moreover, this study analyzed the effects of the geometric parameters of CMS on the non-uniformity coefficient (α) and total pressure drop (ΔP) under the maximum inlet flow condition (Q = 23.40 L/s). The results show that (i) from 0 to 12 s, the flow ratio (β) at the branch ports decreases in the direction of the fluid flow and then increases in the same direction from 12 to 90 s; (ii) as flow growth coefficient (η) increases, α for the maximum inlet Reynolds number (Re) increases slightly, and the difference in α corresponding to the same Re at different time points decreases; (iii) the increase in area ratio (AR) causes the flow rate of the first branch port to rise and the flow of the terminal branch port to decrease. The value of α increases linearly with AR: α = 0.23AR−0.11; (iv) The most economical approach involves adopting a linearly tapered branch ports width design with b 1/b 10 = 1.50, which decreases α by 65.04% while increasing the ΔP by 9.93% compared to the original design. This study can provide a reference for engineers in designing CMS with unsteady flow.

The growing adoption of electric vehicles (EVs) has heightened the demand for efficient thermal management in Li-ion battery packs to ensure safety, performance, and longevity. Conventional liquid cooling techniques often fall short, prompting the use of sustainable alternatives like biodegradable dielectric fluids and advanced immersion cooling techniques. This study evaluates 1 kWh Li-ion battery pack used in two-wheeler EVs cooled via forced flow immersion cooling (FFIC) technique using natural ester fluids: sunflower oil (SFO), cottonseed oil (CSO), and canola oil (CAO), benchmarked against nonbiodegradable mineral oil (MO). A novel flow-field design featuring triangular fins and modified wall structures is proposed to enhance heat dissipation and reduce pressure drop. Among the tested coolants, CSO in the modified design achieved the best thermal performance, reaching maximum pack temperature (MPT) of 35.3°C (≤ 5°C) and pressure drop of 981.25 Pa at 25 L/min-outperforming the standard design, which required 40 L/min and showed a higher pressure drop of 1767.03 Pa. The modified system also enhanced heat transfer coefficient to 102.40 W/m2 K, compared to 86.12 W/m2 K in the baseline case. The results highlight CSO as a superior eco-friendly coolant and emphasize the significance of design optimization and fluid selection in advancing battery cooling for sustainable electric mobility.

Persistent organic pollutants in water, including per- and polyfluoroalkyl substances, pesticides, dyes, and pharmaceutical residues, are difficult to remove due to their high chemical stability, mobility, and toxicity. Traditional approaches based on the use of bulk sorbents or catalysts are often ineffective due to system pressure drops, material losses, limited on-site regeneration, and difficult integration into compact modular units. This review summarises the current state of functional coatings as immobilised, regenerative and modular-ready platforms for reducing persistent organic pollutants. Adsorption coatings are discussed with a focus on MXenes, layered double hydroxide, metal-organic frameworks / covalent organic framewor films, N-doped carbons, and ion-imprinted polymers, highlighting trade-offs between capacity, selectivity, stability in water, and regeneration pathways. Catalytic coatings for advanced oxidation processes are considered in systems based on g-C3N4, TiO2, BiVO4/BiOBr photocatalysts, M–N–C materials for electro-Fenton processes, and perovskite oxides, with an emphasis on radical generation efficiency and stability in realistic aquatic environments. Antifouling and hydrophilic top layers, including PEG-type polymers and zwitterionic polymers, are considered as elements that ensure long-term efficiency by reducing organic and biological contamination. Finally, the role of carriers (ceramic monoliths, polymer ultrafiltration/reverse osmosis membranes, and metal or textile frames) and multilayer architectures is analysed in terms of adhesion, compatibility between layers, and scalable production. Key unresolved issues include coating durability, resistance to delamination, regeneration strategies that do not generate secondary waste, and harmonised metrics for comparing performance in complex water bodies.

Binary mixtures of HFE-73DE and ethyl acetate are investigated as dielectric working fluids for laminar minichannel cooling. Thermophysical properties of the pure components and four mixtures (10/90, 25/75, 50/50 and 75/25 mass % HFE-73DE/ethyl acetate) were measured over the relevant temperature range. Single-phase convective heat transfer tests were then carried out in a heated 1 × 4 × 180 mm minichannel test section under constant heat-flux conditions for pure HFE-73DE. A three-dimensional conjugate CFD model with temperature-dependent liquid properties was developed in Simcenter STAR-CCM+ and validated against these measurements; the average relative temperature difference between CFD and experiment remained below 0.5%, while a grid-convergence study based on the Grid Convergence Index (GCI) confirmed that the numerical uncertainty is comparable to the experimental one. The validated model was subsequently used to predict the axial evolution of wall temperature, fluid-core temperature, velocity and heat transfer coefficient for the four mixtures under identical conditions. The mean Nusselt numbers obtained from CFD were further compared with the classical Shah and London fully developed laminar solution for rectangular ducts, revealing that the present configuration yields values about 35–42% higher than the theoretical prediction owing to asymmetric heating and conjugate heat transfer. The results show that increasing the HFE-73DE mass fraction strengthens convective heat transfer and reduces fluid-temperature rise, while intermediate compositions (50/50 and 75/25) provide a favourable compromise between enhanced heat transfer performance and moderate pressure drop. The study provides guidance for composition selection and the design of dielectric minichannel heat exchangers operating with HFE-73DE/ethyl acetate mixtures.

Pressure drop per unit length is key to limiting the magnitude of flow in vascular systems and fluidic devices. This study presents a straightforward, pressure-responsive method to enhance flow compliance in dendritic microfluidic systems by manipulating the local elasticity. A series of dendritic fluidic networks with varying numbers of elastic elements were developed using replica molding of the elastomer polydimethylsiloxane in a single fabrication step. These elements, consisting of thin elastic membranes, deform under pressure, unlike rigid walls. The geometry and hydrodynamic properties of the networks were characterized by flow velocity measurements and fluorescence microscopy. The most elastic network showed a significant increase in compliance with thin membranes replacing rigid walls, resulting in a non-linear increase in flow rate. Selective placement of elastic elements allowed pressure-controlled flow directionality. This approach reduces pressure loss, does not require complicated fabrication steps, and allows dynamic flow manipulation in specific regions of microfluidic networks.

Polymerase chain reaction (PCR) is vital in biological and medical research, but microfluidic PCR chips often suffer from limited reagent processing capacity and slow thermal response under high flow rates. To address this, we designed three serpentine microfluidic chips with double-sided heaters: a standard serpentine chip (case 1), one with unchamfered channel expansion areas (case 2), and one with chamfered expansions (case 3). Using numerical simulations, we analyzed temperature, velocity, and pressure distributions at flow rates of 75, 125, and 175 μL/min. At 175 μL/min, case 2 showed a 41% higher pressure drop than case 1, but also demonstrated significantly improved thermal performance: the constant-temperature zones were extended by 30 mm, 10 mm, and 30 mm at 95 °C, 72 °C, and 55 °C, respectively; the temperature gradient in expansion zones increased by 1.6 times; and the maximum temperature difference decreased by 80%. Case 2 achieved the best trade-off between thermal performance and flow resistance, making it suitable for high-flow-rate PCR applications.

A specific variational approach has been developed in this article to model the steady flow process of a non-mixing viscous mass obeying non-slip boundary regime system in a perfectly circular pipe. Through consistent mathematical reasoning, concrete analytical results have been obtained for the principal physical quantities of the aforementioned non-mixing viscoussystem, such as the velocity profile (along the pipe radius) in vertical (or non-vertical) pipes, pressure drop, the flow rate of the pipe (Hagen–Poiseuille formula) and the shear stress on the pipe surface. Such issues may be relevant in the operation of oil wells using the gas lift method, in water-cut and sand-producing oil wells, as well as in two-phase and multiphase flow processes. Additionally, it is known that in deep oil and hydrocarbon wells, the temperature increases by 1 degree per 10 meters of depth. Considering that such wells can be extended to several kilometers deep, it becomes evident that, the temperature in the well and the reservoir is an essential actor in all prepossess. As the mixed fluid moves upward from the bottom of the well, the extracted mass begins to cool, but this cooling is not uniform. Therefore, even a homogeneous fluid exiting the well behaves like a non-mixing fluid system, as the viscosity and density of the non-uniformly cooled volume will be unevenly distributed depending on temperature likely to the immiscible system For this reason, it can be considered as the motion of a non-mixing viscous mass. These considerations, along with other practical issues, are the subject of discussion in this article.