- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- EDITOR-IN-CHIEF: Prof. Dr. Isam Janajreh. Khalifa University UAE
- Medium: Online
- ISSN: 1923-7316
- Country: Canada
The International Journal of Thermal and Environmental Engineering (IJTEE) is a high-quality scientific journal devoted to fields of Thermal and Environmental Engineering It aims to provide a highly readable and valuable addition to the literature which will serve as an indispensable reference tool for years to come. The coverage of the journal includes all new theoretical and experimental findings in the fields of Thermal and Environmental Engineering or closely related fields. The journal also encourages the submission of critical review articles covering advances in recent research of such fields as well as technical notes.
INTRODUCTION
The Editor-in-Chief and the Editorial Board are very committed to build the Journal as one of the leading international journals in Thermal and Environmental Engineering in the next few years. With the support of the International Association for Sharing Knowledge and Sustainability (IASKS), it is expected that a heavy resource to be channeled into the Journal to establish its international reputation. The Journal’s reputation will be enhanced from arrangements with several organizers of international conferences in publishing selected best papers of the conference proceedings. The journal is planning to publish 4 issues per year.
AIMS AND SCOPE
The International Journal of Thermal and Environmental Engineering (IJTEE) is a refereed international journal to be of interest and use to all those concerned with research in various fields of, or closely related to Thermal and Environmental Engineering disciplines. The International Journal of Thermal and Environmental Engineering (IJTEE) aims to provide a highly readable and valuable addition to the literature which will serve as an indispensable reference tool for years to come. The coverage of the journal includes all new theoretical and experimental findings in the fields of Thermal and Environmental Engineering or closely related fields. The journal also encourages the submission of critical review articles covering advances in recent research of such fields as well as technical notes.
Latest Articles of IJTEE
Analysis and Sensitivity Studies on Thermoacoustic Engine Stack Temperature Profile Development
IJTEE, Volume-20 , Issue 1 (2023), PP 35 - 39
Published: 12 Oct 2023
DOI: 10.5383/ijtee.20.01.006
by Timileyin Aworinde, Alfiya Simran, Isam Janajreh from Mechanical Engineering Department, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
Abstract: Thermoacoustic engines are devices that convert thermal energy to acoustic energy using the Stirling cycle principle. They have wide importance in refrigeration and power generation, therefore there has been intensified research in this area. High focus has particularly been on exploring ways to improve the efficiency of the thermoacoustic engine, the non- linearity of the temperature profile developed across the stack of the engine poses a hindrance to the efficiency of the engine because the thermal gradient across the stack greatly affects the performance of the engine. This work therefore investigates possible pathways for improving the linearity of the temperature gradient across the stack. Two methods of heating the engines are investigated, namely top heating and side heating. For the former the heat is supplied externally at the top of the resonator while in the latter is done internally at the sides of the stack. Different stack materials and fluid medium are also varied to observe their influence on the temperature gradient across the stack. The results of the conducted analysis show that the internal heating condition has a higher tendency to produce a linear temperature gradient across the stack compared to the top heating. The variation of stack materials shows that the linearity of the temperature gradient of the stack increases with the thermal conductivity of the stack materials as materials with very high thermal conductivities (e.g., diamond) produced a perfectly linear temperature gradient across the stack. For the fluid medium, it is also seen that the linearity of the temperature gradient across the stack improves with increase in specific heat and thermal conductivity of the fluid medium with helium giving the most linear gradient of all the medium investigated. read more... read less...
Keywords: Thermoacoustic engine, thermoacoustic refrigerator, stack heating, stack materials, CFD
Thermal Catalysis Effects of Ca(NO₃)₂, Mg(NO₃) ₂, KNO₃, and Fe(NO₃)₃ on Olive Mill Solid Waste
IJTEE, Volume-20 , Issue 1 (2023), PP 29 - 33
Published: 12 Oct 2023
DOI: 10.5383/ijtee.20.01.005
by Islam Alkahder and Reyad A. Shawabkeh from Chemical Engineering Department, University of Jordan, Amman, Jordan
Abstract: Thermogravimetric Analysis - Differential Scanning Calorimetry (TGA-DSC) was employed in this study to investigate the thermal characteristics of olive mill solid waste (OMSW) both alone and in conjunction with six different compositions of Ca(NO₃)₂, Mg(NO₃)₂, KNO₃, and Fe(NO₃)₃. Emphasis was placed on assessing the impact of these compositions on the thermal behavior and heat flow. The analyses of TGA–DSC for the seven samples, conducted at a 10 K/min heating rate, revealed that the thermal decomposition of the OMSW occurred in three stages corresponding to the removal of water, devolatilization, and the formation of bio-char. Particularly noteworthy was the observation of complete combustion events between approximately 155°C and 240°C for four samples with distinct compositions during TGA testing. These findings underscore the significant influence of nitrate salt compositions on the thermal behavior of OMSW. The insights derived from this study contribute to the optimization of waste-to-energy processes and the refinement of thermal treatment protocols for sustainable OMSW management. read more... read less...
Keywords: Thermogravimetric Analysis, Differential Scanning Calorimetry, Olive mill solid waste, Thermal behavior
Optimizing Gas Turbine Performance: Influence of Angle of Attack and Mist Cooling
IJTEE, Volume-20 , Issue 1 (2023), PP 21 - 28
Published: 12 Oct 2023
DOI: 10.5383/ijtee.20.01.004
by Omar Nasro, Said ELTurk, Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE
Abstract: This work presents a comparative study of the flow over a gas turbine blade aimed at enhancing turbine performance. The study focuses on determining the optimal angle of attack of the fluid and implementing internal turbine blade cooling. Computational Fluid Dynamics (CFD) was employed under varying parameters, including fixed and rotating turbine blade conditions. Precise analysis of temperature and pressure coefficient distributions, as well as torque, enthalpy, thermodynamic power, flow velocity, and mass flow rate were conducted for each setup. Results indicate that the optimal flow attack angle is 60°. Subsequently, mist cooling was simulated as an internal cooling method at the optimum attack angle to examine its effect on blade temperature distribution. Simulation outcomes suggest that implementing mist cooling enhances temperature distribution over the blade and improves turbine performance. read more... read less...
Keywords: Turbine Blades, Turbine Cooling, Gas Turbine, Internal Cooling, Mist Cooling, CFD
Single plate analysis of thermoacoustic refrigerator
IJTEE, Volume-20 , Issue 1 (2023), PP 13 - 19
Published: 07 Feb 2023
DOI: 10.5383/ijtee.20.01.003
by Omar Al-Mufti and Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE
Abstract: Thermoacoustic refrigerator (TAR) or heat pump is a device that uses acoustic sound to pump heat from a lower temperature reservoir. The most distinct feature of thermoacoustic systems is that they do not have moving parts, which makes them reliable with no to low maintenance. TAR can be driven using thermoacoustic engine (TAE) in which the later can be sustainably operated utilizing waste heat or concentrated solar. Also, in contrary to conventional refrigeration methods, TARs do not use environmentally harmful gasses. In this work, a high-fidelity localized model is developed to simulate the flow in a standing wave (straight tabular) thermoacoustic refrigerator. In this localized analysis a subsection domain that runs through two stack halves and stretches nearly 1.5 stack length at each side is considered. The acoustic waves were simulated using oscillating walls at the two domain limits at a given resonance frequency. The model compared favorably to previous experimental and numerical findings. The analysis was done for drive ratios in range of 0.28% to 2%. A 3.2 oC temperature difference is produced at the 2% drive ratio compared to 0.5 oC at the 0.28% ratio. Higher difference can be achieved at higher drive ratio and also larger stack length. read more... read less...
Keywords: Numerical modeling, Thermoacoustic, Refrigerator, Drive ratio, CFD
Thermal Comfort Analysis of Wind Tower Greenhouse Integration System using Ansys
IJTEE, Volume-20 , Issue 1 (2023), PP 07 - 12
Published: 07 Feb 2023
DOI: 10.5383/ijtee.20.01.002
by Sameer Khan, Ruqiya Abdullah Farah, Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
Abstract: Increasing urbanization, a shortage of arable land, and climate change-related weather extremes are some of the challenges facing the production of global food and agriculture due to the estimated global population of 9.6 billion by 2050. As a result, improvements in greenhouse technology and modifications pushed science-based solutions for optimal plant production in all seasons worldwide by adjusting internal climate growing factors. By using passive technology coupled with evaporation cooling from wind towers, significant amounts of energy can be saved, reducing the emissions of greenhouse gases. In this study, the effect of wind tower greenhouse integration on the micro-climatic conditions inside the greenhouse is modeled and simulated. The model is governed by the non-isothermal Navier-Stokes flow in heat, viscous and turbulent flow regimes. The effect of various parameters such as airflow velocity, relative humidity, and temperature in the greenhouse is studied as well as the effect of mist flow rate, and the position of the injector in the wind tower. The results show the optimal design of the greenhouse wind tower integrated system based on the desired temperature and relative humidity within the greenhouse. The final model selected was the flat slope geometry greenhouse with a temperature value of 29.839792°C and relative humidity of 68.34%. read more... read less...
Keywords: Ansys, Evaporative Cooling, Greenhouse, Wind tower
Experimental Study on the Effect of Water as a Working Fluid in Aluminium Heat Pipes
IJTEE, Volume-20 , Issue 1 (2023), PP 01 - 05
Published: 07 Feb 2023
DOI: 10.5383/ijtee.20.01.001
by Salman Hemayet Uddin, Md. Islam, Firas Jarrar, Isam Janajreh from Department of Mechanical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates
Abstract: Thermal management of machines and electronic devices is a matter of high importance. Cooling of electronics becomes much more sensitive in applications related to space because of the difficult constraints and environment. The weight and size are very important parameters as well as the efficiency of the cooling method and heat pipes are considered a very suitable option because of its passive operation and light weight. Different working fluids can be used in a heat pipe but the compatibility of the casing material with the working fluid is a very important parameter. Water aluminum heat pipes are not a common option because they react at temperatures starting from 294 K. In this research the effect of water in the degradation of the performance of aluminum heat pipes is studied. A suitable operation range for the heat load is considered. It is found that at higher loads, the performance of the heat pipe decreased but with the addition of nano particles the performance was compensated by a large measure. read more... read less...
Keywords: Aluminum water heat pipe, Grooved Heat pipe, Hydrogen formation in heat pipe, Nanoparticles
Effect of Tree Shape on Micro-Climate Conditions
IJTEE, Volume-19 , Issue 2 (2022), PP 93 - 33
Published: 28 Dec 2022
DOI: 10.5383/ijtee.19.02.006
by Mohamad Alsheikh, Abdelsalam Alkhalaileh, Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE
Abstract: Optimizing the microclimate conditions has become a very significant demand by public, which led to numerous research in this field. In this study, the effect of different tree shapes and their influence on the microclimate conditions will be studied using computational fluid dynamics (CFD). A baseline geometry was designed with a set of boundaries conditions and its robustness is assessed via different mesh resolutions. Three different tree shapes with the same surface area (long-triangular, short-triangular, and round) were considered and compared. The flow field is governed by the two-dimensional, steady-state, multi-species, and non-isothermal Navier-Stokes equations. In all the tree model configurations, the trees were considered the source of moisture and lower temperature than the surrounding environment. This resulted in increase in the relative humidity of the incoming ambient air and reduction in its temperature. In this analysis the incoming air was considered to follow the common power law atmospheric boundary layer (u/Uinf=(y/Ho)1/7) with an inherited vertical strain rate. The presence of the trees created axial and exaggerated the vertical rate of strains. The results showed that long triangular tree shape had the biggest drop in temperatures with a value of DT= 4.15K (301K local value). It also resulted in a relative humidity value between 15% and 45% which is suitable for the human thermal comfort. read more... read less...
Keywords: Microclimate; CFD; Human thermal comfort; Tree-shape
Synthesis and characterization of activated carbon derived from date palm leaves
IJTEE, Volume-19 , Issue 2 (2022), PP 87 - 92
Published: 27 Dec 2022
DOI: 10.5383/ijtee.19.02.005
by Mubinul Islam, Md. Islam, Hemant Mittal, Saeed Alhassan from Khalifa University of Science and Technology, Abu Dhabi, UAE
Abstract: The use of agricultural waste for the production of activated carbon has gained popularity due to the high carbon content of the raw materials, improve sustainability of the product, and low cost. In this paper, activated carbon (DL-AC) was synthesized from discarded date palm leaves. The activation was done via chemical activation where KOH was used as the activating agent. The final product was characterized using XRD and SEM. The XRD results showed a loss in crystallinity due to the activation process whereas the SEM images showed improved porosity of the activated carbon. Water adsorption studies were carried out at 25 °C and the results were fitted to different isotherm models. The adsorption isotherm reported a maximum adsorption capacity of 0.109 gwat/gads at 0.66 p/po. The multilayer adsorption behavior is best explained using the GAB and FHH isotherm models. read more... read less...
Keywords: Activated carbon; Date palm leaves; Water adsorption
Assessment of Wind Speed and Power Density Using Weibull and Rayleigh Distributions at Turbat, Balochistan, Pakistan
IJTEE, Volume-19 , Issue 2 (2022), PP 77 - 85
Published: 27 Dec 2022
DOI: 10.5383/ijtee.19.02.004
by Asif Jalal, Ussama Ali from Mechanical Engineering Department, University of Engineering and Technology Lahore, Pakistan
Abstract: The meager economic situation, indefinite energy crisis, industrial modernization, and hazardous contamination impulse the empiricist to transcend the attention on renewable energy resources in Pakistan. One of the most rapidly growing renewable energy sources is wind energy. The main goal of this research work is to examine the wind characteristics and wind potential at the site of Turbat, Balochistan, Pakistan. For this purpose, the measured hourly time series data was collected from the Pakistan Meteorological Department (CPDC, Karachi) for 21 months (Jan 2012 – Sep 2013). After evaluating the monthly average wind speed (> 4 m/s), the average value of most probable wind speed (3.83 m/s), the average value of wind speed carrying maximum energy (7.732 m/s), and the standard deviation of the data (1.699 – 3.306), the results are used to statistically evaluate the data by Weibull and Rayleigh distributions for the selected site. The monthly average value of wind power and energy densities of the selected site is 140.145 W/m2 and 101.775 kWh/m2, respectively. A comparison was made between the mean power potential of the site and the power potential assessed using the Weibull and Rayleigh distributions. It was revealed that the Weibull distribution depicted the data more accurately. This statement is further enriched by the assessment of the performance of both distributions with the RMSE, χ2, and R2 tests. read more... read less...
Keywords: Wind energy; Weibull distribution; Rayleigh distribution; Wind energy density; Turbat, Pakistan
The Numerical Analysis of the Suppression of Flow-Induced Vibrations using Slits at the Laminar Regime
IJTEE, Volume-19 , Issue 2 (2022), PP 69 - 76
Published: 27 Dec 2022
DOI: 10.5383/ijtee.19.02.003
by Anas Ghannam, Mohammad Belal and Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
Abstract: The flow over a cylinder is responsible for stimulating vibrations on circular cylinders due to the flow separation and periodic vortex shedding at the downstream area of the cylinder near the wake. Significant damage and fatigue failure transpire when the vortex shedding frequency coincides with the structure's natural frequency, leading to a severe financial and human catastrophe. Therefore, this paper aims to establish a passive control method suppressing the flow induced vibrations (FIVs) by incorporating parallel slits with different sizing examined at various mounting conditions. read more... read less...
Keywords: Flow induced vibrations, Slits, Laminar, Passive flow control
Numerical Analysis of Two Hyperloop Pods
IJTEE, Volume-19 , Issue 2 (2022), PP 63 - 68
Published: 27 Dec 2022
DOI: 10.5383/ijtee.19.02.002
by Mohammad Islayem, Mohammed Tarnini, Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE
Abstract: Hyperloop is forecasted to be the future transportation system for medium distance range. It consists of levitated pods traveling inside a reduced pressure tunnel/tube near the transonic speed. The flow around the pod is limited to Mach speed to avoid the choking and shockwaves formation that can cause damages and destabilization of the pod and the tube. The most crucial parameter in the hyperloop traveling system is the aerodynamic drag. In this study, numerical flow simulation of compressible steady air flow has been done on the hyperloop pod traveling inside the low-pressure tunnel environment. Two-dimensional axisymmetric simulations were carried out to assess the flow and aerodynamic forces exerted on the pods under varying speed (25 to 350 m/s) and separation distance (10.75, 21.5, 43, 86 m) between two pods. For all the cases, Mach number =1 flow speed is reached at a value between 150 to 200 m/s and the shockwaves start appearing on the 2nd pod at a value between 200 to 250 m/s. Results show that shockwave appeared at the 1st pod at separation distance of 86 m and speed 350 m/s. Overall, the pressure drag has more impact on the total drag than the friction drag especially at the 2nd pod. The total drag obtained at the 1st pod in a multiple pod model is less than the total drag in a single pod model, while it is higher at the 2nd pod when compared with a single pod model. read more... read less...
Keywords: Hyperloop, Multiple pods, Steady flow, Drag coefficients
Performance Analysis of Thermographic Cameras Applied to Wood Damage Detection
IJTEE, Volume-19 , Issue 2 (2022), PP 55 - 62
Published: 27 Dec 2022
DOI: 10.5383/ijtee.19.02.001
by António Costa, Rui Pitarma from Polytechnic Institute of Guarda, Guarda, Portugal
Abstract: Wood is a crucial component of the green economy of the 21st Century. From house construction to innovative daily applications and products, wood is one of the most sustainable resources. However, as a natural material, it suffers deterioration with time. Infrared thermography may provide an excellent potential for detecting internal damage. Although the prices of infrared cameras have dropped recently, getting the best value for money and choosing the right camera for wood inspection is a significant challenge. Before choosing an infrared camera, the operator needs to consider several parameters, such as the temperature range, spectral range, thermal sensitivity, resolution, spatial resolution, accuracy, optics and focus, to make an informed decision. This study aims to evaluate the performance of two infrared cameras, a high-end model and a mid-range model, in visual wood damage detection. For this purpose, samples of different wood species with induced damage were observed using active thermography. Our results suggest that, for technical purposes such as qualitative studies, resolution and thermal sensitivity may be more important parameters than accuracy. The results achieved are an important contribution when deciding which infrared camera to purchase. read more... read less...
Keywords: Infrared Cameras, Thermal Sensitivity, Resolution, Accuracy, Performance, Wood Damage Detection