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.
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.
IJTEE, Volume-20 , Issue 1 (2023), PP 13 - 19
Published: 07 Feb 2023
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
IJTEE, Volume-20 , Issue 1 (2023), PP 07 - 12
Published: 07 Feb 2023
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
IJTEE, Volume-20 , Issue 1 (2023), PP 01 - 05
Published: 07 Feb 2023
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
IJTEE, Volume-19 , Issue 2 (2022), PP 93 - 33
Published: 28 Dec 2022
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
IJTEE, Volume-19 , Issue 2 (2022), PP 87 - 92
Published: 27 Dec 2022
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
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
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
IJTEE, Volume-19 , Issue 2 (2022), PP 63 - 68
Published: 27 Dec 2022
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
IJTEE, Volume-19 , Issue 2 (2022), PP 55 - 62
Published: 27 Dec 2022
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
Assessment of ultrasound assisted coalescence of water-in-crude oil emulsion: Influence of piezoelectric transducer material under batch and continuous conditions
IJTEE, Volume-19 , Issue 1 (2022), PP 47 - 54
Published: 26 Oct 2022
by Idowu Adeyemi, Mahmoud Meribout, Lyes Khezzar, Nabil Kharoua, Khalid AlHammadi from Department of Mechanical Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, Department of Electrical Engineering and Computer Science, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates, and Department of Mechanical Engineering, Ecole Nationale Polytechnique de Constantine, Constantine, Algeria
Abstract: In this work, the potentiality of lead free ultrasound (US) materials towards crude oil emulsion demulsification was assessed. The assessment is crucial because of the detrimental environmental and health impacts of lead zirconate titanate, which is widely used for US coalescence presently. The production or utilization of lead zirconate titanate (PZT) results in the release of vaporized hazardous lead oxide (PbO) at elevated temperature or dissolution of poisonous lead into aqueous medium. Hence, the analysis of the effect of different piezoelectric material type (PZT, polyvinylidene fluoride (PVDF) and lithium niobate (LiNbO3)) on domain acoustic pressure distribution and the subsequent coalescence of binary droplets under batch conditions was conducted. The lead-free piezoelectric materials (PVDF and LiNbO3) were assessed with the PZT in order to determine their viability for droplet coalescence. The piezoelectric materials were subjected to mechanical oscillation under resonance in order to allow for optimum performance. Moreover, the US coalescence was examined under continuous flow conditions to determine coalescence behavior and performance during online emulsion treatment. The eigen-frequency analysis provided the resonance frequencies of 19.61, 26.04 and 57.80 kHz for PVDF, PZT and Lithium niobate, respectively. Moreover, the acoustic pressure in the emulsion domain varied in magnitude and distribution. The order of the coalescence time for the binary droplets followed the order PZT<PVDF<LiNbO3. Furthermore, increasing the flow velocities resulted in slight reduction in the coalescence time and energy consumed for the different piezoelectric materials evaluated. read more... read less...
Keywords: Piezoelectric transducer, Ultrasound, Coalescence, Demulsification, Lead free, Crude Oil Emulsion
IJTEE, Volume-19 , Issue 1 (2022), PP 29 - 45
Published: 26 Oct 2022
by Omar Ahmed Al-Mufti and Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE
Abstract: Thermoacoustic is the science that studies the conversion of the heat into acoustical sound and vice versa. The conversion of heat to acoustic power is done through Thermoacoustic engine (TAE). This generated acoustic power can be converted to another and useful form such as mechanical or electrical energy. On the other hand, 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. Thermoacoustic engine can recycle any source of waste heat and use sustainable heat like concentrated solar. Also, in contrast to conventional refrigeration methods, thermoacoustic refrigerator spares the usage of environmentally harmful gases that is daunting the centralized cooling industry. There is no doubt the thermoacoustic technology has been considered in various applications with some unspoken advancement. In this manuscript we intend to review the fundamentals of thermoacoustics and highlight their recent developments. Additionally, analytical simulation of thermoacoustic refrigerator will be discussed and validated against experimental published work. The goal is to reveal the effect of different parameters on the performance in an attempt to establish design guidelines for an improved technology metrics. The future prospects of thermoacoustic refrigeration are also presented at the end of this study. read more... read less...
Keywords: Thermoacoustic engine; Thermoacoustic refrigerator; Thermal and viscous penetration depth; Standing and traveling wave
IJTEE, Volume-19 , Issue 1 (2022), PP 23 - 28
Published: 19 Sep 2022
by M Mubashir Farid, Samia Sadaf, M Shahid Farooq, Ussama Ali from Department of Mechanical Engineering, University of Engineering and Technology Lahore, Pakistan
Abstract: This paper investigates the effect of nanofluids in a flat-tube heat exchanger on the heat transfer under the influence of constant heat flux using computational fluid dynamics (CFD) analysis. Two nanofluids: Titanium Oxide (TiO2)/water and Aluminum Oxide (Al2O3)/water were used with nanoparticles of diameter 10 nm. A two-phase approach with a mixture model is adopted in the CFD analysis. The heat transfer coefficient was evaluated at Reynolds number of 1750 utilizing various volume concentrations of nanoparticles (1%, 3%, 5%, and 7%). It was observed that an increase in the concentration of the nanoparticles resulted in an increase in the value of heat transfer coefficient. The results observed at 7% volume concentration, using two-phase approach, showed 5% and 8% enhancement in the heat transfer coefficient for TiO2/water and Al2O3/water, respectively, when compared with the results of single-phase technique. read more... read less...
Keywords: Flat tube, Heat transfer coefficient, Two-phase approach, Nanofluids