Journal of Advanced Research in Numerical Heat Transfer

Numerical Analysis on Frictional Heat Effect in Polyether-Ether-Ketone (PEEK)/Steel Pair by using OpenFOAM Model

Mohd Zaki Bahrom — 2024-06-28

The PEEK material has been applied to a sliding bearing system in a power plant system because of its high mechanical durability. In the solid friction of the PEEK materials, the frictional heat becomes the important factor because the temperature increase due to the frictional heat causes the rapid increase of the frictional coefficient of the specimen. To maintain the low frictional coefficient of the PEEK materials, an effective cooling method for the PEEK materials needs to be developed. In this study, the passive cooling method, which attaches the heat sink to the PEEK materials, was suggested. For evaluating the suggested cooling method of the PEEK materials, the calculation model adopting OpenFOAM, which is open-source software, has been developed. Adopting some functions and libraries of OpenFOAM, the frictional heat, heat resistance, and heat transfer coefficient on the heat sink were modelled. The sliding bearing experiment was conducted and time variation of the temperature and friction coefficient in the ring specimen were measured. The temperature variation in the ring specimen was compared with the calculation result. From the numerical calculation results, the developed calculation model could simulate the temperature-time variation of the ring obtained in the experiment, when the variation of the frictional coefficient, heat resistance, and heat transfer coefficient was modelled appropriately. Based on the friction and wear test results, by applying a heat dissipation mechanism to the ring test piece, the calorific value of the PEEK material can be reduced, and it is stable. It was suggested that the friction was maintained.

CFD Analysis of Gas-Dynamic and Heat Transfer Processes in a Propulsion System Using Polymer Fuel

Andrii Dreus — 2024-06-28

In the presented work, a computer model of thermodynamic and gas-dynamic processes in a rocket engine of a new type, which uses solid polymers as fuel is considered. The design feature is the presence of a central body - a gasification chamber, where solid polymer fuel is decomposed into volatiles. To conduct the research, a preliminary thermodynamic analysis of the combustion of gasification products was carried out. Based on the results of the thermodynamic analysis using the mathematical model of the turbulent flow of viscous compressible gas, the processes of gas dynamics and heat transfer in the chamber and nozzle of the rocket engine were simulated. Analyses are made for the geometry of a real experimental sample of a polymer-fueled rocket engine developed at Oles Honchar Dnipro National University (Ukraine), which has passed the first successful tests. As a result of CFD simulation, dynamic and thermal fields in the combustion chamber and engine nozzle were obtained, and ways of further improvement of the design were determined.

Mixed Convection Boundary Layer Flow over a Solid Sphere in AL203-Ag/Water Hybrid Nanofluid with Viscous Dissipation Effects

Eddy Elfiano — 2024-06-28

The current study aims to investigate how heat transfer and skin friction develop by modifications in the fundamental advantages of fluids in the presence of mixed convection boundary layer flow over on a sphere in hybrid nanofluids. The numerical solutions for the reduced Nusselt number, local skin friction coefficient temperature profile, and velocity profiles are discovered and clearly presented. The Eckert number, the mixed convection parameter λ, and the nanoparticle volume fraction are all investigated and described. It is found that increasing the volume percentage of nanomaterial in nanofluid enhanced the value of the skin friction coefficient. The low density of nano oxides in hybrid nanofluids, such as alumina, also contributes to reduced friction between fluid and body surface. The findings of a computational investigation demonstrate that the use of a hybrid nanofluid, composed of nanometal and nano-oxide in the form of , has the potential to decrease skin friction while maintaining heat transfer characteristics comparable to that of Ag/water nanofluid. The findings in this publication are new and will be useful to boundary layer flow researchers. It can also be applied as a guideline for experimental investigations with the goal of reducing the cost of operation

Modeling and Simulation of Drilling Gas Mixing Process with Various Conditions in Oil and Gas Pipeline Network

Bayu Triwibowo — 2024-06-28

This research aims to model and simulate the gas drilling mixing process with various conditions in the inlet gas flow. This mixing process is very crucial because it can affect the phase stability in the storage tank. Based on this, the gas that has been mixed must be ensured that it is in a perfectly mixed condition before entering the storage tank. The simulation method used in this research is Computational Fluid Dynamics (CFD) with ANSYS Fluent software. The data used as input in this simulation includes flow velocity, temperature, pressure and drilling gas composition. The simulation results are expected to show that flow velocity and pressure have a significant effect on the drilling gas mixing process in the pipe flow. In addition, the differences in the composition of the drilling gas also have an impact on the mixing process, where the more diverse the composition of the drilling gas, the more difficult it is to mix the gas homogeneously. However, by using baffle plates as a barrier and agitator in the pipe, the simulation results show that the mixing of drilling gas can be significantly increased.

Computational Fluid Dynamic (CFD) Simulation Thermal Performance and Hydrodynamic Erosion in Circulation Fluidized Bed (CFB) Boiler at PLTU West Kalimantan

Eflita Yohana — 2024-06-28

Computational Fluid Dynamics (CFD) has been widely used to study Circulation Fluidized Bed (CFB) combustion processes. Analysis of mixed fuel between coal and biomass from PKS (palm kernel shell) in the combustion process that occurs in the boiler at West Kalimantan power plant is carried out by mixing the addition of PKS fuel by 20%, 40%, 60%, and 80%. The simulation uses model set-up data, material properties, and boundary conditions according to PJB (Pembangkitan Jawa Bali) Ketapang's experimental data. Then an analysis was carried out with a fluid flow velocity of 3.2 kg/s and particle sizes of 150 μm, 300 μm, 400 μm, and 500 μm on the erosion rate that occurs on the furnace walls due to sand particles present in the combustion process material at the Steam Power Plant (PLTU). Based on the simulation results of mixing fuel between coal and PKS variations of 20% - 80%, the temperature decreased from 1180℃ – 920.03℃ due to differences in fuel heat. Whereas the erosion rate in the simulation has increased from 0.000189 kg/s – 0.001886 kg/s due to differences in the size of the sand particles and the velocity of the mass flow rate of the particles.