Drying of mint leaves in forced convection solar dryer

In this present work, performance study on drying mint leaves under the metrological conditions. Intensity of radiation falls on the absorber plate which transfers heat to forced air-flow inside the galvanized iron tube. Drying experiment carried out with 1 kg of mint leaves taken for drying process under the different mass-flow rate of 0.75 m/s and 1.25 m/s in serpentine flow of air. Performance of the collector and drying efficiency were 30.33% and 1.63% in first day at 0.75 m/s mass-flow rate and in the second day collector, the drying efficiency were 29.41% and 1.89% at the mass-flow rate of 1.25 m/s. The mass-flow rate of air decreased with increasing collector and drying efficiency.

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Performance study of an inlet in supersonic flow

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410011426672 ◽

2012 ◽

Vol 227 (1) ◽

pp. 159-174 ◽

Cited By ~ 7

Author(s):

Mohammad R Soltani ◽

Mohammad Farahani

Keyword(s):

Mach Number ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Free Stream ◽

Characteristic Curve ◽

Pressure Recovery ◽

Internal Boundary ◽

Performance Study ◽

Free Stream Mach Number

The performance characteristics of an axisymmetric inlet at its design and off-design operational conditions are experimentally investigated. The model is tested for wide ranges of free stream Mach numbers, M∞ = 1.5–2.5, and mass flow rates. For each test, the pressure recovery, the mass flow passing through the inlet and the pressure distribution over the spike and the cowl are measured. In addition, the shock wave formed in front of the inlet is visualized. The characteristic curve of the inlet is then obtained for each free stream Mach number. As the Mach number is increased, the pressure recovery is reduced, but the maximum value of the mass flow rate grows up. Variations of the mass flow affect the surface pressure over both the front portion of the cowl and the entire surface of the spike. Further, it has changed both pressure and Mach number at the end of the diffuser, which would consequently affect the performance of the propulsion system. In addition, contrary to the internal boundary layer, the external one far from the cowl lip has been found to be almost independent of the inlet mass flow rate for a constant free stream Mach number.

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Analytical and Experimental Investigation to Determine the Variation of Hottel–Whillier–Bliss Constants for a Scaled Forced Circulation Flat-Plate Solar Water Heater

Journal of Solar Energy Engineering ◽

10.1115/1.4031213 ◽

2015 ◽

Vol 137 (5) ◽

Author(s):

U. C. Arunachala ◽

M. Siddhartha Bhatt ◽

L. K. Sreepathi

Keyword(s):

Mass Flow Rate ◽

Heat Loss ◽

Mass Flow ◽

Flow Rate ◽

Loss Coefficient ◽

Absorber Plate ◽

Forced Circulation ◽

Solar Water ◽

Scale Thickness ◽

Overall Heat Loss Coefficient

Fixed tilt flat-plate solar thermal collectors, popularly known as solar water heaters, still remain as one of the most interesting technologies for utilization of solar energy. The system performance deteriorates due to scaling because of the continuous use of hard water as feed water. The present study deals with the experimental and analytical approach to determine the variation of Hottel–Whillier–Bliss (H–W–B) constants (which compactly represent the efficiency characteristics of a solar water heater) due to variation in solar power input and degree of scaling in case of forced circulation system (FCS) without considering the variation of input power to the circulating pump. Indoor tests are performed with a copper tube to investigate the flow characteristics. This forms a part of conventional FCS, in place of the usual nine-fin tube array in a full-fledged collector. In indoor tests, electrical heating is favored to simulate solar radiation level. Various energy parameters are determined and compared by incorporating the developed numerical code FLATSCALE. Variation between experimental and analytical mass flow rate, overall heat loss coefficient, and H–W–B constants with simulated solar radiation level is plotted. In scaled condition, the drop in instantaneous efficiency is due to both scale thickness and reduced water flow rate. Scale thickness acts as an additional thermal conductive resistance between absorber plate and flowing water. Overall heat loss coefficient increases as absorber plate temperature is high during reduced flow rate. The maximum deviation observed is 21.68% in mass flow rate, 14.64% in absorber plate mean temperature, 7.86% in overall heat loss coefficient, and 12.04% in instantaneous efficiency. Compared to a clean tube, a highly scaled tube of 3.7 mm scale thickness indicates a drop of 4.76% in instantaneous efficiency and 40.28% in mass flow rate. It is concluded that the growth of scale in FCS does not affect the instantaneous efficiency significantly because of the margin in heat carrying capacity of water in spite of high drop in the flow rate.

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Influence of absorber plate shape factor and mass flow rate on the performance of the PVT system

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2019.04.070 ◽

2019 ◽

Vol 156 ◽

pp. 692-701 ◽

Cited By ~ 15

Author(s):

Harendra Pal Singh ◽

Aayush Jain ◽

Arvind Singh ◽

Swati Arora

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Shape Factor ◽

Absorber Plate ◽

Plate Shape

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Analytical and Experimental Investigation to Determine the Variation of H-W-B Constants for a Scaled Forced Circulation Flat Plate Solar Water Heater

Volume 6B: Energy ◽

10.1115/imece2013-63453 ◽

2013 ◽

Author(s):

Arunachala Chandavar ◽

Siddhartha Bhatt ◽

Sreepathi Krishnamurthy

Keyword(s):

Mass Flow Rate ◽

Heat Loss ◽

Mass Flow ◽

Flow Rate ◽

Circulation System ◽

Absorber Plate ◽

Forced Circulation ◽

Solar Water ◽

Scale Thickness ◽

Overall Heat Loss Coefficient

Fixed tilt flat plate solar thermal collectors, popularly known as solar water heaters still remain as one of the most interesting technologies for utilization of solar energy. The system performance deteriorates due to scaling because of continuous use of hard water as feed water. The present study deals with the experimental and analytical approach to determine the variation of H-W-B (Hottel–Whillier–Bliss) constants (which compactly represent the efficiency characteristics of a solar water heater) due to variation in solar power input and degree of scaling in case of forced circulation system without considering the variation of input power to the circulating pump. Indoor tests are performed with a copper tube to investigate the flow characteristics. This forms a part of conventional forced circulation system, in place of the usual nine-fin tube array in a full fledged collector. In indoor tests, electrical heating is favored to simulate solar radiation level. Various energy parameters are determined and compared by incorporating the developed numerical code FLATSCALE. Variation between experimental and analytical mass flow rate, overall heat loss coefficient, H-W-B constants with simulated solar radiation level are plotted. In scaled condition, the drop in instantaneous efficiency is due to both scale thickness and reduced water flow rate. Scale thickness acts as an additional thermal conductive resistance between absorber plate and flowing water. Overall heat loss coefficient increases as absorber plate temperature is high during reduced flow rate. The maximum deviation observed is 21.68 % in mass flow rate, 14.64 % in absorber plate mean temperature, 7.86 % in overall heat loss coefficient and 12.04 % in instantaneous efficiency. Compared to a clean tube, a highly scaled tube of 3.7 mm scale thickness indicates a drop of 4.76 % in instantaneous efficiency and 40.28 % in mass flow rate. It is concluded that the growth of scale in forced circulation system does not affect the instantaneous efficiency significantly because of the margin in heat carrying capacity of water inspite of high drop in the flow rate.

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Effect of Temperature at Tray Position on Drying of D.ark Re.d Oni.on-slice.s at Elevated Air Velocity

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.c6238.049420 ◽

2020 ◽

Vol 9 (4) ◽

pp. 293-296

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Moisture Ratio ◽

Convective Drying ◽

Flow Rate Ratio ◽

Effect Of Temperature ◽

Drying Process ◽

Air Velocity ◽

Drying Time

The convective drying process is used to dry onion-slices. The drying experiments are conducted at a drying temperature of 50oC, 60oC, 70oC, and at an air velocity of 1.99, 3.54, 5.66, and 7.52 m/s. The objective is to study the influence of tray position on drying of dark red onion. The work diverges in analyzing drying constants at air velocity beyond 2 m/s. The moisture ratio for the middle tray is greater compared to the top and bottom tray. A smaller moisture ratio is observed for 60°C compared to 50 and 70°C. Moisture removal per unit mass flow rate ratio is lowest observed for bottom tray with 60°C. The ratio of moisture content and mass flow rate for 60 and 70 °C, displays a downward trend with drying time. The randomness in the drying rate at 60 °C and 70 °C is comparatively lesser than 50 °C.

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Theoretical Study of New Configuration of Photovoltaic/Thermal Solar Collector (PV/T) Design

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.772.681 ◽

2013 ◽

Vol 772 ◽

pp. 681-687 ◽

Cited By ~ 12

Author(s):

M.I. Fadhel ◽

Sakhr M. Sultan ◽

Saqaff Ahmed Alkaff

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Solar Collector ◽

Theoretical Study ◽

Spiral Flow ◽

Absorber Plate ◽

Insulating Material ◽

Pv Panel ◽

T System

The combination of solar thermal and PV technologies leads to form a single module called PVT system. This system is able to produce heat and electricity simultaneously. In this paper, a new configuration and design of PV/T system are proposed, and a theoretical study of this system is evaluated. The PV/T consists of certain layers which are the glass, air gap, PV panel, absorber plate and insulating material layer. The monocrystalline PV and spiral flow absorber plate are used in this study. The results of the system performance under typical sunny climatic Malaysian condition are presented. The maximum thermal and electrical efficiencies obtained are 64.4 % and 12.13%, respectively. The effect of mass flow rate on the outlet water temperature is also evaluated. It is shown that the optimum mass flow rate for the designed system is between 0.005 and 0.075 kg/s.

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Transient computational fluid dynamics investigations on thermal performance of solar air heater with hollow vertical fins

Thermal Science ◽

10.2298/tsci170531297d ◽

2018 ◽

Vol 22 (6 Part A) ◽

pp. 2389-2399 ◽

Cited By ~ 2

Author(s):

Duraisamy Jagadeesh ◽

Ramasamy Venkatachalam ◽

Gurusamy Nallakumarasamy

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Thermal Performance ◽

Experimental Work ◽

Thermal Efficiency ◽

Solar Air Heater ◽

Outlet Temperature ◽

Absorber Plate ◽

Air Dryer

Evaluation of experimental thermal performance of a single pass solar air dryer is compared with a transient CFD studies is performed. Vertical hollow plates are placed below the absorber plate and compared against the flat solar absorber plate for its performance improvement. Effect of mass-flow rate, the outlet temperature of air is computationally analyzed in comparison with the experimental work, transient boundary conditions for CFD like ambient temperature, solar insolation are taken from the experimental work, and computational results are in good agreement of with experimental results with maximum error percentage of 10%. Thermal efficiency was increased with increase in mass-flow area for without fin configuration, for a specific mass-flow rate thermal efficiency had a good improvement with fin configuration than the without fin configuration.

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