Journal of Advanced Research in Experimental Fluid Mechanics and Heat Transfer

Study on Capillary Pipe Length Variation on Fishing Refrigeration Box Performance

Thu, 10 Jul 2025 00:00:00 +0800

One of the components that significantly influences the performance of a cooling (refrigerator) box onboard a fishing ship is its capillary pipes. To achieve high system efficiency, the size of the capillary pipes must be adjusted to the compressor's capacity. This is because the size of the capillary pipe significantly affects the frictional resistance, which could lead to reduced system efficiency. To find out the length of the capillary pipe that is best at reducing the temperature of the fishing refrigeration box, experiments were carried out in this study with 3 (three) variations of capillary pipe lengths with the same diameter. It was found that the best temperature drop occurred at a capillary pipe length of 2.5 meters with the lowest temperature of 3.4 °C. In comparison, the less-than-maximum temperature drop occurred in the 2-meter capillary pipe length with a final temperature of 13.4 °C. Changes in capillary pipe length also impact the Coefficient of Performance (COP) of the fishing refrigeration system. The highest COP was obtained for the case with the longest capillary pipe length.

Effects of Oxyhydrogen (HHO) Gas Supplementation on Performance and Emissions of a 1.6L Spark Ignition (SI) Engine at Various Load Conditions

Thu, 10 Jul 2025 00:00:00 +0800

This study investigates the effects of Oxyhydrogen (HHO) gas supplementation on the performance and emission characteristics of a 1.6L, 4-cylinder Multi-port Fuel Injection (MPI) spark ignition engine under varying load conditions. A dry-cell HHO generator utilizing potassium hydroxide (KOH) electrolyte at different molarities (0.3M, 0.5M, 0.7M, and 1.0M) was employed, with the generated gas supplied directly to the intake manifold just before the throttle body. The engine was tested in stock condition using only RON95 gasoline, while HHO testing was conducted in a dual-fuel configuration, combining RON95 gasoline with HHO gas. Performance and emissions were evaluated across engine speeds from 1500 to 3000 rpm at throttle valve positions of 25%, 50% and 75%. Brake power and torque were enhanced by up to 3.67% and 3.40%, respectively, with the most notable improvements occurring at 3000 rpm of engine speed. Brake-specific fuel consumption was reduced by up to 1.94%, although the highest molarity (1.0M) occasionally led to efficiency penalties. Emission measurements indicated significant reductions in CO and HC emissions, up to 11.90% and 22.98%, respectively, while monitoring CO2, NOX, O2, and lambda/air-fuel ratio (AFR). The most favorable HHO concentration range was identified as 0.5–0.7M. These findings demonstrate that controlled HHO supplementation can effectively enhance fuel economy and emission performance in SI engines without major mechanical modifications, contributing to the advancement of more environmentally sustainable internal combustion technologies.

AerospaAcer Valve-Holding Chamber Velocity Profile using Wind Tunnel Experiment

Riyadhthusollehan Khairulfuaad, Nor Zelawati Asmuin, Muhammad Kamal Arif Amir — Thu, 10 Jul 2025 00:00:00 +0800

of the respiratory system. Although pressurized metered-dose inhalers (pMDIs) are widely used for asthma medication delivery, improper administration can lead to suboptimal drug delivery. To enhance medication deposition in the lungs, spacers, such as the AerospaAcer device, are employed to slow down aerosolized particles. This study investigates the aerodynamic performance of the AerospaAcer valve-holding chamber through wind tunnel experiments, focusing on various valve configurations, including the Duckbill and Cross-Slit valves. Wind tunnel testing was conducted at airflow rates of 30, 60, and 90 L/min, simulating typical inhalation conditions. Results revealed that the AerospaAcer with the Duckbill valve achieved the maximum pressure and velocity at the outlet, indicating optimal drug delivery potential. In contrast, the AerospaAcer without any valve configuration exhibited the highest pressure and velocity at the chamber's entrance. Drug particle retention rates were measured at 85.4%, demonstrating a 5% improvement over commercially available valve-holding chambers. Furthermore, the cylindrical design of the AerospaAcer combined with the Duckbill valve enhanced lower respiratory tract deposition by 3% compared to baseline VHC designs. These findings suggest that the AerospaAcer with a Duckbill valve can significantly improve drug delivery efficiency, reduce backflow, and enhance medication deposition in the lower respiratory tract. The data from this wind tunnel experiment provides valuable insights into the optimization of inhalation devices and their role in advancing respiratory drug delivery strategies.

Process Control in Torrefaction: Design and Experimental Investigation of a Custom Oven using Fuzzy Logic Algorithms

Thu, 10 Jul 2025 00:00:00 +0800

In heating systems, overshoot refers to the phenomenon where the temperature exceeds the intended setpoint prior to stability, resulting in inefficiencies, potential deviations from expectations, and safety hazards. This project introduces a custom-made designed oven (CMDO) utilising Fuzzy Logic Control (FLC). It analyses the behaviour of the CMDO and implements 36 FLC-based rules to minimise overshoot, optimising factors such as rise time and settling time. Experimental studies on the oven are being conducted to analyse its behaviour with varying PWM (Pulse Width Modulation) across a temperature range of 100 to 500 degrees.The oven's performance was evaluated by collecting data using a K-type thermocouple sensor, with temperature readings recorded in a CSV file. The collected data were analysed to assess oven performance, followed by fine-tuning if the performance was deemed unsatisfactory. The implementation of FLC has resulted in an average improvement of overshoot by up to 90% across temperatures ranging from 100 to 400 degrees, with a significant enhancement in settling time at temperatures below 200 degrees. However, temperatures above 300 degrees have exhibited a slight increase in settling compared to conditions without FLC. The results indicate that torrefaction is a more effective pre-treatment method for municipal solid waste (MSW) than the conventional thermal drying process. The torrefaction results were compared with previous research, revealing similar trends and thereby validating the operation and yield of the developed system.

Visualization Analysis of Flow with Smoke on Airfoils and Flaps

Meddy Kooshartoyo, Eflita Yohana, Muchammad Muchammad, Ivranza Zuhdi Pane — Thu, 10 Jul 2025 00:00:00 +0800

Flow visualization using smoke over airfoils and flaps provides valuable insights into the aerodynamic behavior of these surfaces, particularly in identifying flow attachment, separation, and wake characteristics. This study explores the interaction of airflow with clean airfoils and configurations involving deflected flaps, employing smoke as a tracer in a controlled wind tunnel environment. The investigation focuses on analyzing laminar-to-turbulent transition, boundary-layer behavior, flow reattachment, and the formation of vortices and wake patterns. Results demonstrate the influence of flap deflection angles on lift, drag, and flow separation, highlighting the role of slots in mitigating separation and enhancing aerodynamic performance. This approach offers a practical methodology for optimizing airfoil and flap designs in applications requiring efficient lift-to-drag ratios and delayed stall conditions.

Investigation of Regression Rate Enhancement of HTPB/Paraffin Fuel in the Hybrid Rocket Motor Utilizing High Entropy Alloys Energetic Additives

Thu, 10 Jul 2025 00:00:00 +0800

Hybrid rocket motors are being looked at by the aerospace industry as an alternative to solid and liquid rocket power systems that is safer to use, move and handle. HRM still has several weaknesses that need to be explored such as low regression rate, poor combustion efficiency and also the ability to operate in large sizes. This research aims to conduct performance analytical and experimental comparison of HTPB/Paraffin fuel doped with HEA energetic additives for thrust, specific impulse and regression rates. The research analysed the Hybrid Rocker Motor's performance using ProPeP to determine the specific impulse and characteristic velocity of various propellant mixtures for comparison. Twenty-one HTPB/Paraffin fuel samples, with varying concentrations of energetic additives HEA and Ammonium Perchlorate, were fired on a lab-scale static bench equipped with a feeding system, combustion chamber, nozzle and data acquisition system for measurement and analysis. Analysed the results and determine the regression rate improvement of HTPB/Paraffin fuel with HEA additives and the correlation between regression rate and oxidizer mass flux. The experiment's findings indicated that adding HEA, Ammonium Perchlorate and Aluminium increased the regression rate. HEA demonstrates a 79% improvement, markedly lower than the 128% boost found with AP. Nonetheless, HEA enhances the thermal stability of the fuel mixture. ensuring uniform performance across different oxidizing conditions, as demonstrated in the hybrid formulation containing ammonium perchlorate (AP) and HEA. The integration of AP and HEA enhances heat distribution, hence promoting combustion stability.

Indoor Environmental Quality of Naturally Ventilated Classrooms in Tropical Indonesia Post-COVID-19

Rosady Mulyadi, Baharuddin Hamzah, Yusaumi Ramadhanti Fitri Taufik — Thu, 10 Jul 2025 00:00:00 +0800

Following the COVID-19 outbreak in late 2019, classroom instruction in tropical Indonesia shifted from online learning to face-to-face settings by 2021, driven by declining infection rates and strict health protocols. This transition replaced air conditioning with natural ventilation, maximising window and vent openings, posing challenges to Indoor Environmental Quality (IEQ). This study evaluates thermal, visual, acoustic, and air quality conditions in five Makassar high school classrooms using a mixed-methods approach. Quantitative measurements recorded air temperature (28–30.48°C), light intensity (322 lux), background noise (64.39 dB), and CO/CO2 concentrations (17 ppm/533 ppm), while questionnaires captured student perceptions. Thermal conditions, per SNI 03-6572-2001, near the "comfortably warm" upper limit (25.8–27.1°C), yet 54% of students reported discomfort, with 90% preferring cooler temperatures. Light intensity exceeded SNI 03-2396-2001’s 250 lux, rated "bright" by 68% of students, though glare risks emerged. Acoustic levels surpassed the WHO’s 35–40 dB guideline, with 81% hearing noise frequently, yet 66% were undisturbed. Air quality remained within safe limits (CO < 35 ppm, CO2 < 1000 ppm). Natural ventilation ensures air quality and reduces viral risks but compromises thermal and acoustic comfort, necessitating passive design solutions in tropical climates.

Hydrogen Application as a Renewable Fuel in the Internal Combustion Engine and Fuel Cell towards Zero Carbon Emission: A Technical Review

Alfiy Alfatarizqi, Semin Semin, I Made Ariana, Kumaran Kadirgama — Thu, 10 Jul 2025 00:00:00 +0800

Global efforts to lessen environmental effects, particularly in the marine industry, which make up around 90% of global trade, are led by the switch from traditional fossil fuels to renewable energy. Carbon emissions from cargo ships, including tankers, container ships, and bulk carriers, have become a significant concern due to the rising need for marine transportation. With a primary focuses on shipboard applications, this study compares internal combustion engines with fuel cell technology to assess hydrogen as a potential alternative fuel for the marine industry. One benefit of using hydrogen as a combined fuel with other fuels is that it can cut greenhouse gas emissions by as much as 40%. Fuel cell technology is more efficient than hydrogen-fuelled ICEs, reaching up to 60%, while internal combustion only reaches 20-25%. In addition, fuel cells produce no carbon emissions, making them more environmentally friendly. However, significant challenges include the cost of hydrogen production, limited storage and distribution infrastructure. The study also discusses technical and operational aspects, including hydrogen storage methods, such as compressed storage, cryogenic storage, and electrochemical storage, and emissions challenges faced by hydrogen-fuelled ICEs, such as increased NOx emissions due to high combustion temperatures. The analysis concluded that hydrogen fuel has great potential to support the decarbonization of the maritime sector. This review paper offers an extensive examination of the opportunities and obstacles linked to the utilization of hydrogen as a renewable fuel, specifically in the context of fuel cell engines, and internal combustion, and establishes a basis for promoting sustainable renewable energy within the maritime sector.

Vortex Control at Pump Intake using Double- and Triple-Plate Floor Splitters

Thu, 10 Jul 2025 00:00:00 +0800

Vortices are one of the main contributors to efficiency loss and damage issues in centrifugal pump components, particularly those aligned with the axis that facilitates water transfer from the reservoir. This problematic scenario arises due to a non-optimal pump reservoir design and irregular water flow entering the reservoir. The unsteady flow disrupts the pump's functionality, leading to inefficiency and potential damage over time. However, this issue can be mitigated by installing anti-vortex devices (AVD) around the pump reservoir. The ANSI/HI 9.8 2018 standard outlines various AVD designs, specifying that the swirl angle in the flow should not exceed 5° to ensure efficient operation. Here, we use customised double- and triple-plate floor splitters (DPFS and TPFS). A floor-type flow separator plate is an effective measure to reduce swirls and vortices in the pump intake flow. Vortex intensity was measured using a swirl meter, and it was found that installing a plate in a single-pump system could reduce swirl angle by approximately 60%. The approach used involved visualizing flow structures with a particle image velocimetry (PIV) device to obtain data on vortex intensity before and after the plate installation. In an effort to improve AVD design, six plate samples with different dimensions were tested. This study also examined the effects of adding plates to the AVD design to optimise flow separator design in various pump reservoir geometries. We found that the DPFS 260 mm (25 mm) setup effectively minimised vortex formation with a high reduction in vorticity. The results of this experiment can provide guidance for reducing vortex problems in pump reservoirs, which in turn can save time and cost in pump system planning and management.

Enhancing Energy and Exergy Efficiency in Hot Air Drying System using IoT-Controlled Adaptive Air Recirculation

Thu, 10 Jul 2025 00:00:00 +0800

Traditional hot air drying systems consume substantial energy, often accounting for up to 60% of industrial operational costs, presenting significant challenges for sustainable manufacturing processes. Current drying systems rely on static air recirculation settings that cannot adapt to real-time changes in moisture content, leading to inefficient energy utilization and poor energy quality optimization. This study develops an Internet of Things (IoT)-controlled hot air drying system featuring adaptive air recirculation to enhance both energy and exergy efficiency through dynamic real-time control. We investigated the effects of varying air recirculation rates (0%, 25%, 50%, and 75%) across three temperature settings (50°C, 60°C, and 70°C) on specific energy consumption (SEC) and exergy efficiency using fresh pork slices as experimental material with IoT-enabled servo motor control for adaptive recirculation adjustment. The findings indicate that higher temperatures combined with increased air recirculation substantially reduce SEC, achieving reductions of up to 50% under optimal conditions (70°C and 75% recirculation). Furthermore, exergy efficiency improved by up to 42.1%, reflecting a significant decrease in exergy destruction. This IoT-enabled adaptive system demonstrates a robust strategy for minimizing energy consumption and optimizing energy quality in drying processes, providing critical insights for sustainable and high-efficiency drying applications.

Experimental Study and Thermal Examination of a Practicable Helium Liquefaction Prearrangement using a Pervasive Gifford-McMahon Cryocooler

S.A. Mohan Krishna, K.B. Vinay, Amruth E. — Thu, 10 Jul 2025 00:00:00 +0800

Liquid helium has been attained by cooling helium gas to 4 K or -2690C. Many laboratories around the globe compel liquid helium as a working medium for low temperature investigation. In current scenario, liquid helium generating systems are exclusive and momentously compatible. Helium recondensation or liquefaction system is the unsurpassed platform to liquefy or to condense the helium in many applications viz., Nuclear Magnetic Resonance (NMR), Magnetic Resonance Imaging (MRI) and Superconducting Quantum Interference Devices (SQUIDS). These applications make use of liquid helium as refrigerator. In this research, the experimental investigation of a small-scale liquefaction system for helium gas using two-stage GM cryocooler has been carried out. The experimentation using 100 cm3 yielded a result of, initial collection of liquid in upright liquefaction system takes about 335 minutes and subsequent collection of liquid helium (batch liquefaction) takes place with the time interval of nearly 45 minutes at a pressure of approximate 1bar. In case of inverted system, the initial collection of liquid helium takes about 170 minutes and subsequent collection of liquid (batch liquefaction) takes place with the time interval of nearly 30 minutes at a pressure of approximate 1 bar. From the above result, it has been concluded that the liquefaction rate is a function of pressure exists inside collection vessel and the orientation in which it is operating. The study meticulously reviews the design, setup and experimentation stages, highlighting the thermal performance and efficiency of the cryocooler, with key insights into the cooling capacity, setup parameters and thermal measurements.

Study on Flow Velocity Effect to Corrosion Rate of Mild Steel

Thu, 10 Jul 2025 00:00:00 +0800

The use of iron and steel as the main material for shipbuilding is still dominant. However, iron and steel are highly reactive and corrode in seawater and it has become the biggest causes of ship plate damages. In this study, the calculation of relatively fast corrosion propagation on low-carbon steel plates by comparing the corrosion rate on moving samples will be investigated. In this study, researchers examined the comparative effect of flow speed, time, pH, and salinity on specimens. Researchers used a method that looks at the initial mass of a sample before it is placed in a corrosive environment over a period of time, then reweighs the sample to measure the weight lost due to corrosion. Changes in flow velocity affect the corrosion rate of each specimen. The highest corrosion rate was found in specimens immersed with a flow speed of 0.3 m/s at 4.741 mm/year, and the lowest was found in specimens immersed with a flow velocity of 0.1 m/s at 0.244 mm/year. The faster the flow of water, the greater the corrosion rate. The variation of the corrosive media also affects the corrosion rate. The corrosion rate can increase as the pH decreases and the level of salt or salinity in the corrosive media increases. The highest corrosion rate value is found in specimens immersed in media with a pH of 5 and a salinity of 3.7% at 4.741 mm/year, and the lowest is found in specimens immersed in media with a pH of 9 and a salinity of 3.3% at 0.244 mm/year.

Adsorption of Nickel as Waste Contaminant using Nano-Sustainable-Based Particle Material: From a Bibliometric Perspective

Asep Bayu Dani Nandiyanto , Risti Ragadhita, Ahmad Mudzakir — Thu, 10 Jul 2025 00:00:00 +0800

Adsorption is a crucial area of study, particularly in material technology and environmental management. A literature evaluation, bibliometric analysis, and visualization of scientific publications about the subject of adsorption from 2014-2024 are the objectives of this work. By using publication data from the Scopus database, which has gathered and retrieved 1,522 publication papers, bibliometric analysis was carried out. This study examined several factors, such as (i) the year-over-year increase in research publications; (ii) the most cited articles; (iii) the most influential countries, journals, and institutions; (iv) the features of research documents; (v) productive research fields; and (vi) network and overlay visualization. The analysis's findings indicate that rising environmental consciousness around the world led to a notable rise in publications between 2021 and 2022. The most significant research uses eco-friendly nanoparticles for sustainable adsorption. While Chinese organizations like the Chinese Academy of Sciences and the Ministry of Education of the People's Republic of China dominate research contributions, motivated by local industry demands, the Journal of Colloid and Interface Science is the major journal in this field. The nations that have made the biggest contributions to research are China, India, and the United States. Chemistry, environmental science, chemical engineering, and materials science comprise the majority of the publications (83.3%). Three primary groupings are depicted in the topic visualization: particles, sustainability, and removal. The latest research trends include studies on the removal of organic and inorganic pollutants, sustainability, adsorption cycles, material reuse, and the development of new adsorbents. This study provides a systematic and objective view of research trends related to adsorption, which is expected to be a reference for researchers and practitioners to understand the development and future direction of research in this field.

Adiabatic Combustion Chamber Pyrolysis for Palm Kernel Shell Biochar Production

Mohd Kamel Wan Ibrahim, Mohd Khusairi Kamis, Mohd Suffian Misaran — Thu, 10 Jul 2025 00:00:00 +0800

The rapid expansion of the palm oil industry has raised concerns about the increasing generation of waste, particularly Palm Kernel Shells (PKS). However, these byproducts present promising opportunities for conversion into valuable resources such as charcoal. To facilitate this process, a combustion chamber was designed and constructed to conduct pyrolysis for PKS charcoal production. This study aims to evaluate the performance of the combustion chamber in consistently reaching and maintaining a temperature of 600 degree using mangrove wood as fuel. Additionally, the quality of PKS charcoal was assessed by measuring its electrical resistance with an ohm meter, providing a quantitative indicator of carbonization. The calorific value of charcoal briquettes produced from powdered PKS charcoal was also analysed. Performance testing of the combustion chamber revealed that it achieved a maximum temperature of 795 degree at T1 and 671 degree at T2 confirming its capability to sustain the pyrolysis process. The measured electrical resistance of the PKS charcoal was 1.73omega, indicating low resistance and, consequently, a high-quality charcoal product. The moisture content of the PKS charcoal was determined to be 4%, signifying a relatively low moisture level, which is crucial for maintaining high charcoal quality. Furthermore, the calorific value of the PKS charcoal was found to be 21.552 MJ/Kg, categorizing it as a moderate-to-high-quality fuel source. Charcoal with a higher calorific value releases more energy during combustion. In conclusion, this study demonstrates that palm kernel shell waste from the palm oil sector can be effectively converted into high-quality charcoal, highlighting its potential as a valuable and sustainable resource.