Rigid spray polyurethane (RSPU) was commercially used as an injection in crack walls or soil surfaces to enhance material performance, increase lifetime, and save operating costs. The limitation of the RSPU nozzle was reported as easily clogging when sprayed out to the insulation and crack surface area and the finished product was less aesthetically pleasing. In this study, the RSPU nozzle of flat fan nozzle, 180° angle (Design A), Hollow cone nozzle, 60° angle (Design B), and Full cone nozzle, 90° angle (Design C) were prepared by using the SOLIDWORKS software. The effect of different pressures for RSPU nozzle design at the ranges of 4Mpa, 5MPa, and 6MPa was examined by ANSYS FLUENT software. The velocity of the outer spray nozzle shows a significant increase with increasing inlet pressure of the RSPU nozzle. The results reveal that the highest velocity of RSPU was obtained at the Hollow cone nozzle (Design B) as compared to (Flat fan nozzle) Design A and (Full cone nozzle) Design C at 394.249 m/s at 4MPa, 442.327 m/s at 5MPa and 485.37 m/s at 6MPa, respectively. The distribution droplet area shows the Design B spray formation had wider area coverage at 60° and exhibited that the injection nozzle spray was scatted and uniform at 6MPa. RSPU shows the velocity increased, distribution droplet increased, and output volume spray was decreased at the increasing of injection pressure. Hence, in this study was suggested that the size of RSPU nozzle design must be made at the ranges of 60° to 90° of outlet nozzle to obtain a good RSPU area. In conclusion, design B is the most effective for RSPU nozzle and is useful in injection cracking and insulation materials applications.

In this study, the efficacy of aluminum oxide (Al2O3) nanofluids at a 2% concentration for enhancing heat transfer in shell and tube heat exchangers is evaluated. By employing SOLIDWORKS for the innovative design and Computational Fluid Dynamics (CFD) for simulation, an improvement in heat transfer efficiency over traditional hot water systems is identified. Emphasizing the unique properties of Al2O3 nanofluids in augmenting heat transfer rates, the role of advanced CAD and simulation tools in engineering practices is highlighted. Results confirm nanofluids' benefits in improving thermal management systems, indicating their potential to decrease energy consumption and operational costs. Furthermore, the exploration of a novel design for heat exchangers, inspired by but distinct from existing market standards, suggests new avenues for the application of nanofluids in various industrial settings, marking a step towards more energy-efficient technologies.

This study investigates the actuation of sidewall sprinklers in large-scale buildings with high-ceilinged atriums, addressing the challenges of unique architectural configurations. Compliance with NFPA 101 requires automatic sprinkler systems, including atrium areas, in these buildings. To maintain aesthetic considerations, design engineers, particularly in the middle east, often propose sidewall sprinklers as an alternative to traditional ceiling sprinklers. This research assesses whether the sidewall sprinklers would actuate during a fire using Fire Dynamic Simulator (FDS). The findings indicate that sidewall sprinklers will fail to actuate if the fire is located at the centre of the atrium, even if the edge of the fire area is below the sprinklers. Furthermore, the study emphasizes the importance of using an FDS mesh resolution (D*/dx) of 6 or finer resolution when measuring temperatures near the flame or fire plume to ensure accurate evaluations of sprinkler activation. These findings provide valuable insights for design engineers and authorities, assisting in decision-making processes related to fire safety measures, system designs, and regulatory compliance.

Up to now, there is no developed ‘universal’ turbulence model in CFD simulation, so employing an appropriate turbulence model is crucial for accurately predicting the hydrodynamics of a ship, especially for submarines. This study focuses on investigating the impact of turbulence models on the predicted results in frictional and pressure resistance components and flow features around the submarine at different ship velocities by the CFD method. Four various turbulence models consisting of the Reynolds Stress Model, realizable k-ε two-layer, standard k-ω, and SST k-ω turbulence models are investigated in this study. The obtained numerical results demonstrate variations in resistance and the flow patterns around the submarine due to the effect of turbulence model. Based on the obtained results, the paper points out that, the choice of turbulence model significantly affects the frictional resistance of the submarine and the SST K-ω turbulence model provided the highest level of accuracy in comparison with experimental data. The model employed in this research is the DARPA SUBOFF submarine model

Depending on specific needs and workloads, several racks with varied component densities may be used in a data center. As server density increases, porosity decreases, and the opposite is also true. A frequently used method called cold aisle containment separates hot air and cold air flows in data center settings to improve cooling effectiveness. In this paper, the performance of a data center is investigated using computational fluid dynamics, and the influence of porosity on cold aisle containment is evaluated using well-established non-dimensional performance parameters. The value of RTI without containment increased with an increase in porosity and a maximum RTI of 217 was found with a porosity of 0.75. Regardless of the rack number and porosity, containment provides the optimal RTI values. The results indicate that the SHI and RHI values for rack 1 for all porosities, without confinement, are outside of the permissible range and at higher porosities containment has no significant effects on SHI and RHI. RCILO values for racks 2, 3, and 4, with or without containment, fall within the 80-85% range, indicating temperatures below 13°C. RCIHI value is 1 for all cases considered indicating no rack is out of the recommended temperature of 25°C.

Due to global warming, population growth, and urbanisation, demands for space cooling in buildings have significantly increased. Mechanical vapour compression cooling technology is relatively mature, well-understood and most commonly used globally. However, they suffer from high energy consumption and adverse environmental impact due to the refrigerants used. As ambient temperature and humidity have significant effects on the performance of vapour compression systems, this paper experimentally and numerically investigates their impact on the performance of vapour compression air conditioning system in terms of power consumption and cooling capacity. It was concluded that at ambient humidity of 55%, as the ambient temperature increases from 22 °C to 40 °C, the compressor temperature has increased from 46 °C to 59 °C which increased its power consumption from 751.2 to 935.52 Watts, giving an increase of 10.24 Watts for every one degree of ambient temperature increase. Also, as ambient humidity in-creased from 32% to 88%, the power consumption increased from 739.2 Watts to 853.2 Watts, an increase of 114 Watts. A validated CFD (Computational Fluid Dynamics) model was developed and predicted a loss in the enthalpy change from 11.7kJ/kg.d.a to 3.6kJ/kg.d.a. due to ambient temperature increasing from 22 °C to 40 °C and a loss of enthalpy change from 12.857kJ/kg.d.a to 5.524kJ/kg.d.a. due to increasing the ambient air humidity from 32% to 88%. This work high-lighted the impacts of ambient conditions on the performance of vapour compression cooling system in terms of increased power consumption and loss of cooling capacity.

This article presents a numerical simulation of high hydrogen/air flames using the Lagrangian transported PDF method. This method enables the calculation of fluid composition changes resulting from convection and reaction without the need for modelling, while requiring modelling for molecular mixing. Consequently, the accuracy of calculations in this L-PDF method heavily relies on an accurate representation of the mixture model term. The Euclidean model, which provides a better description of physical mixing processes, is well-suited for modelling the molecular mixing term EMST. Additionally, the accuracy of this model depends on the value of the mixing constant, representing the ratio between the mechanical time scale and the scalar time scale. Two algebraic models for the mixing constant have been implemented in the computational code, employing a well-defined function to calculate this ratio for each cell. These models contribute to memory and CPU time savings. To account for turbulence and its interaction with physical phenomena, the RSM model is employed due to its ability to identify different areas of turbulent stresses. Hence, the primary objective of this study is to evaluate the capabilities of these algebraic models in predicting scalar fields within such flames. Overall, the predictions align well with experimental data, affirming the validity of these models.

Heat transfer is commonly utilized in diverse industrial applications, including the manufacturing of paper, the cooling of electrical devices, and the synthesis of new substances. Hence, this study aims to investigate the effect of heat generation/absorption on the steady magnetohydrodynamic (MHD) flow and heat transfer of Al2O3-Cu/H2O hybrid nanofluids over a permeable stretching/shrinking wedge. By using similarity transformation techniques, the governing equations of the hybrid nanofluids are transformed into similarity equations. The similarity equations are numerically solved using the MATLAB software's built-in bvp4c package. The findings show that hybrid nanofluids are seen to improve thermal efficiency in comparison to conventional fluid. In relation to heat transfer rate, the increase of magnetic parameters from 0.00 to 0.10 and 0.15 contributes approximately 12.3% and 18.8%, respectively. Meanwhile, as the heat generation parameter increases, the heat transfer rate decreases leading to an inefficient thermal system. The findings of this study are anticipated to contribute to the knowledge base of scientists and researchers in the field.

This study evaluates the tsunami forces exerted on a terrestrial structure caused by a collision-induced tsunami. Conventionally, assessing these forces relies on the inundation depth of the colliding tsunami passing without the presence of the terrestrial structure. However, it is essential to consider the inundation depth and incident fluid velocity, as both significantly influence the resulting tsunami forces. In this research, ANSYS Fluent 17.2 is employed to simulate excitation sources using a Defined Function (UDF) code within a C++ framework. The dynamic meshing technique is adopted to replicate the interactions between the bore pressure of the tsunami and an idealised vertical wall structure across three distinct water levels. Computational Fluid Dynamics (CFD) modelling demonstrates the proposed methodology's capability to offer precise impact pressure distributions concerning geographical and temporal aspects. The findings reveal specific instances: at a water depth of 10 m, the maximum Froude number is attained at 3.5 and 6.9 seconds, corresponding to a maximum pressure value of 3.9x105 Pa at 3.85 seconds for a water flow velocity of 20 m/sec. Similarly, for a water depth of 12 m, the most significant Froude number is observed at 3.95 and 6.9 seconds, with a peak pressure value of 1.8x105 Pa at 4.6 seconds, associated with a water flow velocity of 15 m/s. Additionally, at a water depth of 14 m, the maximum Froude number is reached at 4.95 and 7.1 seconds, accompanied by a maximum pressure value of 7.4x104 Pa at 4.85 seconds for a water flow velocity of 10 m/s.

Seakeeping is influenced by several factors such as speed, ship hull shape, and the direction of the waves (heading angle). In this research, the crew boat is analyzed using the 3D Diffraction method to obtain the response of the ship's motion at regular waves. The study focused on analyzing the sea motion of the crew boat at different wave periods (2.58 s, 4.12 s, 5.67 s, and 7.22 s) and variation of ship speeds (0 Knot, 3 knots, 6 knots, 9 knots, 12 knots, 15 knots, and 18 knots). It used input data including the heading angle of the wave (μ) which is 180° and at a wave height of 0.5 m. The numerical analysis was carried out to determine the ship's seakeeping and compare it with NORDFORSK 1987 criteria, and also to identify the Motion Sickness Incidence (MSI) of the crews on board. Based on the results obtained, the seakeeping value of the ship accepted the criteria of NORDFORSK 1987 up to a speed of 9 knots, starting at a speed of 12 knots it does not accept the criteria. As for the operability, the comfort level of the crew while on board has an MSI index of 0% for 0 Knot, and an MSI index for 18 knots is 4.46% of the total crew of the ship namely only 1 person from 25 persons will likely feel sea sickness.