The Experts below are selected from a list of 4923 Experts worldwide ranked by ideXlab platform
Apurba Layek - One of the best experts on this subject based on the ideXlab platform.
-
numerical analysis for nusselt number and heat transfer augmentation on solar air heater roughened with square rib roughness on the Absorber Plate
2019Co-Authors: Amit Kumar, Apurba LayekAbstract:Heat transfer rate on solar air heater system is generally achieved by suitable modification of Absorber Plate surface with acceptable geometry of rib roughness. In this paper a numerical study is performed using CFD based computational analysis of heat transfer augmentation equipped with the square rib roughness created artificially on the Absorber Plate. The 2D analysis is performed using ANSYS 16.2 Code with RNG k-e turbulence model to investigate the heat transfer and fluid flow characteristics. The augmentation of heat transfer on increase of Reynolds number enhance the Nusselt number which is referred as energy gain ratio with the use of rib roughness was examined and their relative evaluation has been plotted. The parameter which is considered for the range of analysis is taken as relative roughness pitch (P/e), relative roughness height (e/D) and the Reynolds numbers (Re) ranging from 3800-18000. The enhancement of heat transfers due to rib roughness on the Absorber Plate have been compared with those for smooth ducts for the same flow and thermal boundary condition to determine the energy gain ratio of solar air heater. The result obtained by the present investigation shows that the maximum value of energy gain ratio is found to be about 1.93 times the smooth duct for the studied range of parameters.
-
nusselt number and friction factor correlation of solar air heater having twisted rib roughness on Absorber Plate
2019Co-Authors: Anup Kuma, Apurba LayekAbstract:Abstract A study is carried out providing integrated roughness over Absorber Plate of solar air heater to improve its potential for heat transfer augmentation. A number of experiments are conducted with twisted roughness to pursuit test results for heat transfer augmentation along with friction factor phenomena. The experiments stand with a relevant range of flow parameters as Reynolds number from 3500 to 21000, and geometric parameters such as relative roughness pitch from 6 to 10, rib inclination angle domain from 30° to 90° and twist ratio from 3 to 7. Finally, the correlations are developed for the Nusselt number and the friction factor in terms of flow parameter and roughness geometries and compared with experimental results which are reasonable and eventually satisfactory. The enhancement of heat transfer as well as friction factor are obtained and compared with smooth conventional duct for the same flow circumstances. The results are analyzed to pursuit optimum condition of roughness parameters to achieve the best performance.
-
Energetic and exergetic performance evaluation of solar air heater with twisted rib roughness on Absorber Plate
2019Co-Authors: Anup Kumar, Apurba LayekAbstract:Abstract The present works conducts a stochastic analysis for numerical optimization for energetic and exergetic efficiencies of solar air heater with twisted rib roughness on Absorber Plate. These efficiencies are evaluated considering design parameters and temperature rise parameter. The energy efficiency criterion does not consider the pumping power to blow air through the duct. Therefore, it becomes an exigent work to evaluate effective and exergetic efficiency to estimate energy distribution of solar air heater. The thermal behavior is taken in account through Nusselt number and friction factor correlations as function of different geometrical configuration performed experimental work for twisted rib roughness and compared with smooth Plate and previous results. The exergetic efficiency criterion characterized optimum roughness parameters in terms of temperature rise parameter and insolation. A geometrical configuration of relative pitch roughness of 8, rib orientation angle of 60°, twist ratio of 3 and temperature rise parameter of 0.0125 m2 K/W reported maximum enhancement in thermal, effective and exergetic efficiencies as 1.81, 1.79 and 1.81 times over smooth Plate. The comparisons between simulated and experimental results within 6% at maxima considering within acceptable limit. Additionally, present methodology facilitates to prepare design plot for roughness parameter without introducing much investment for real experimentation and also addresses to investigate novel artificial roughness to enhance thermal performance of solar air heater.
-
thermo hydraulic performance of solar air heater having twisted rib over the Absorber Plate
2018Co-Authors: Anup Kumar, Apurba LayekAbstract:Abstract Researchers are working to enhance the performance of the solar air heater through infusing various turbulators of different geometry and size over the Absorber Plate. The present work studied the effect of twisted rib over the Absorber Plate of solar air heater. Experimentations are performed varying roughness parameters such as relative roughness pitch (P/e) values of 6–10, rib inclination angle (α) in the range of 30°–90°, twist ratio (y/e) of 3–7 and Reynolds number in the range of 3500–21000, to acquire its influences on heat propagation rate and flow friction. The heat transfer and flow friction characteristic with this roughness are compared with a smooth surface for similar flowing conditions. The maximum enhancement for heat propagation characteristic and friction factor had been noticed to be 2.58 and 1.78 times that of smooth surface respectively. The thermo-hydraulic performance had been evaluated for the optimum range of roughness geometric parameters.
-
performance analysis of trapezoidal corrugated solar air heater with sensible heat storage material
2017Co-Authors: D V N Lakshmi, Apurba Layek, Muthu P KumarAbstract:Abstract The energy and exergy analysis of solar air heater having Absorber Plate corrugated in the shape of trapezoid along with sensible heat storage material is carried out. Gravel is used as a sensible heat storage material and placed below the Absorber Plate. Thermal performance analysis of solar air heater with and without sensible heat storage materials is carried out and compared with flat Plate solar air heater. The parameters such as solar radiation intensity, temperatures at various positions in solar air heater, and daily thermal and exergy efficiency are calculated. The average daily thermal efficiency of flat Plate solar air heater and that having trapezoidal corrugation are 8.5% and 12.2% respectively, while trapezoidal corrugated Absorber with sensible heat storage material shows thermal efficiency of 36.6%. The maximum exergy efficiency obtained having trapezoidal corrugated Absorber with sensible heat storage material is 12.56%.
M Mohanraj - One of the best experts on this subject based on the ideXlab platform.
-
Experimental thermodynamic analysis of a forced convection solar air heater using Absorber Plate with pin-fins
2019Co-Authors: S. Sivakumar, K. Siva, M MohanrajAbstract:This research paper deals with the experimental thermodynamic analysis of a forced convection solar air heater using pin-fin Absorber Plate and compared with the standard flat Absorber Plate. The experiments were carried out during the months of February 2018 and March 2018 at Coimbatore city in India. The performance parameters such as, outlet air temperature, energy efficiency, thermohydraulic efficiency, and exergy efficiency are used for performance comparisons. The results showed that the pin-fin Absorber Plate has about 17 °C higher outlet air temperature when compared to the flat Absorber Plate. The energy efficiency of a forced convection solar air heater using pin-fin Absorber Plate was found to be 3% to 12% higher when compared to flat Absorber Plate with 2% to 11% higher exergy efficiency. The results confirmed that forced convection solar air heaters using pin-fin Absorber Plate is having significant performance improvement in thermodynamic performance with minimum pressure drop across the air heater duct.
-
thermodynamic performance of forced convection solar air heaters using pin fin Absorber Plate packed with latent heat storage materials
2016Co-Authors: Arul R Kumar, Ganesh B Babu, M MohanrajAbstract:In this work, the thermodynamic performance of a forced convection solar air heater (FCSAH) was evaluated using two different Absorber Plate configurations, namely a flat Absorber Plate and a pin–fin Absorber Plate packed with latent heat storage material (paraffin wax). The experiments were carried out under the meteorological conditions of Coimbatore city in India. The parameters such as outlet air temperature, thermo-hydraulic efficiency and exergy efficiency were evaluated with reference to solar intensity, ambient temperature and ambient wind velocity. An artificial neural network (ANN) model was developed to simulate the thermodynamic performance of a FCSAH using flat Absorber Plate and pin–fin Absorber Plate packed with paraffin wax to have a realistic performance comparison. The ANN-predicted results are found to be closer to the experimental values with a maximum fraction of absolute variance, minimum root-mean-square errors and minimum coefficient of variance. The results showed that the pin–fin Absorber Plate packed with paraffin wax has additional heat storage for the period of 3 h with 2–5 °C enhanced outlet air temperature when compared to the flat Absorber Plate. The FCSAH using pin–fin Absorber Plate packed with paraffin wax has 3–35 % higher thermo-hydraulic efficiency with 2–15 % higher exergy efficiency when compared to the flat Absorber Plate. The results confirmed that pin–fin Absorber Plate packed with paraffin is a good option to enhance the thermodynamic performance of a FCSAH.
S Youcefali - One of the best experts on this subject based on the ideXlab platform.
-
numerical and experimental study of a solar equipped with offset rectangular Plate fin Absorber Plate
2006Co-Authors: S Youcefali, J Y DesmonsAbstract:A mathematical model that allows the determination of the thermal performances of the single-pass solar air collector with offset rectangular Plate fin Absorber Plate is developed. The model can predict the temperature profile of all the components of the collector and of the air stream in the channel duct. Into the latter are introduced the offset rectangular Plate fins, which increase the thermal heat transfer between the Absorber Plate and the fluid. The offset rectangular Plate fins, mounted in a staggered pattern, are oriented parallel to the fluid flow and are soldered to the underside of the Absorber Plate. They are characterized by high heat transfer area per unit volume and generate the low pressure losses. The experimental results of the air stream temperature will be compared with the results obtained by the theoretical model suggested.
-
study and optimization of the thermal performances of the offset rectangular Plate fin Absorber Plates with various glazing
2005Co-Authors: S YoucefaliAbstract:The low thermophysical characteristics of air used as a heat transfer fluid in the solar collectors with thermal conversion require a fully developed turbulent flow. This increases the thermal heat transfer between the Absorber Plate and the fluid, which clearly improves the thermal performances of the solar collector with obstacles arranged into the air channel duct. In the present work, we introduce, in solar collector, the offset rectangular Plate fins, which are used in heat exchangers. An experimental investigation carried out showed the generated enhancement of thermal performance. The offset rectangular Plate fins, mounted in staggered pattern, are oriented parallel to the fluid flow and are soldered to the underside of Absorber Plate. They are characterized by high heat transfer area per unit volume. High thermal performances are obtained with low pressure losses and in consequence a low electrical power consumption by the fan in comparison to the flat Plate collector. The experimental results are all so compared by using two types of transparent cover; double and triple.
Balaram Kundu - One of the best experts on this subject based on the ideXlab platform.
-
analytic method for thermal performance and optimization of an Absorber Plate fin having variable thermal conductivity and overall loss coefficient
2010Co-Authors: Balaram KunduAbstract:The Absorber of a collector receives solar energy which is delivered to the transport medium to be carried away as useful energy. During this process, temperature of the Absorber Plate increases and therefore, thermophysical parameters engaged to determine the thermal performance of an Absorber Plate varies with temperature of the Plate. The present study demonstrates analytically to determine the performance of an Absorber Plate fin with temperature dependent both thermal conductivity and overall heat loss coefficient. The decomposition method is proposed for the solution methodology. An optimum design analysis has also been carried out. A comparative study has been executed among the present results and that of existed in the published work, and a notable difference in results has been found. Finally, unlike published work, dependency parameters on the performances and optimum design have been highlighted.
-
performance analysis and optimization of Absorber Plates of different geometry for a flat Plate solar collector a comparative study
2002Co-Authors: Balaram KunduAbstract:This paper presents a comparative study on the performance and optimization of several profile shapes namely, rectangular, trapezoidal and rectangular profile with a step change in local thickness (RPSLT). This analysis concentrates on the performance and optimization of RPSLT. A modification has been suggested for the analysis of RPSLT Absorber Plate that was observed by Hollands and Stedman [Solar Energy 49 (1992) 493]. The result indicates that there is optimum fin efficiency of trapezoidal profile for constant Plate volume. The RPSLT profile of Absorber Plate is superior to other profiles because of higher performance and less difficulties in fabrication.
-
performance analysis and optimization of Absorber Plates of different geometry for a flat Plate solar collector a comparative study
2002Co-Authors: Balaram KunduAbstract:This paper presents a comparative study on the performance and optimization of several profile shapes namely, rectangular, trapezoidal and rectangular profile with a step change in local thickness (RPSLT). This analysis concentrates on the performance and optimization of RPSLT. A modification has been suggested for the analysis of RPSLT Absorber Plate that was observed by Hollands and Stedman [Solar Energy 49 (1992) 493]. The result indicates that there is optimum fin efficiency of trapezoidal profile for constant Plate volume. The RPSLT profile of Absorber Plate is superior to other profiles because of higher performance and less difficulties in fabrication.
Chuan Jiang - One of the best experts on this subject based on the ideXlab platform.
-
numerical simulation investigation on thermal performance of heat pipe flat Plate solar collector
2017Co-Authors: Dongwei Zhang, Hanzhong Tao, Mimi Wang, Zishuai Sun, Chuan JiangAbstract:Abstract Based on finite volume method, the thermal performance of three-dimensional heat pipe flat-Plate solar collector is studied under steady-state. A physical model of two-phase closed thermosyphon is established by taking account of the thermal resistance networks. The temperature field of Absorber Plate and flow condition as well as temperature counter of the air gap between the Absorber Plate and glass cover of a simulation case are described. Structure parameters such as the heat pipe diameter, the evaporator length, the Absorber Plate thickness and the inclination angle on the thermal performance of the collector are deeply discussed and analyzed. The results show that: The heat pipe diameter of 12 mm is helpful for increasing the useful heat gain of water and instantaneous efficiency. Increasing the evaporator length can increase the average useful heat gain of water but decrease the instantaneous efficiency of the collector. Increasing the Absorber Plate thickness can both improve the average useful heat gain of water and instantaneous efficiency of the collector. The inclination angle between 30° and 45° is appropriate when the collector placed towards south in Nanjing of China. The research results are helpful to design and optimize the heat pipe flat-Plate solar collector.