Evaporative cooling efficiency of a fogging system in a rose greenhouse

2006 ◽  
Vol 46 (9) ◽  
pp. 1231 ◽  
Author(s):  
H. H. Ozturk
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Water Reservoir ◽  
Absolute Humidity ◽  
Experimental Period ◽  
Ventilation Rate ◽  
Air Flow Rate ◽  
Nozzle Clogging ◽  
The Difference ◽  
Water Softener

The objective of this study was to investigate the effect of a fogging system on the microclimate of a rose greenhouse. The experiments were carried out in a multi-span plastic greenhouse, 106 wide by 205 m long, made of 11 spans. The fogging system consisted of a water softener and filters to prevent nozzle clogging, a water reservoir, pumps and a pressure regulator, and fog generating nozzles. Three nozzle lines with 82 fog generating nozzles were installed in each span of the plastic greenhouse. At each nozzle line, 82 fog generating nozzles were uniformly located at 2.5 m nozzle spacing. The fog generating nozzle parameters were determined to characterise the efficiency of the fogging system based on air flow rate and evaporation flow rate. The results showed that the fogging system was able to keep the air temperature inside the plastic greenhouse 6.6°C lower than that outside. The average ventilation rate of the plastic greenhouse was 13.6 m3/s during the experimental period. The efficiency of the fogging system ranged from 11.7 to 80%. The efficiency of the fogging system increased as the difference between the dry-bulb temperature and wet-bulb temperature rose. The results indicated that air relative humidity inside the plastic greenhouse was increased by 25% on average by means of the fogging system examined in this study. The evaporation flow rate varied between 130 and 1223 g/h.m2, whereas the air flow rate ranged from 39.3 to 298 kg/h.m2. Fogging system efficiency increased linearly with evaporation flow rate and the absolute humidity difference between the inside and outside air.

Sealing Effects of Squeeze Air Film

1986 ◽  
Vol 108 (4) ◽  
pp. 594-597 ◽  
Author(s):  
H. Takada ◽  
S. Kamigaichi ◽  
H. Miura
Keyword(s):  
Flow Rate ◽  
Vibration Amplitude ◽  
Ambient Pressure ◽  
Air Flow ◽  
Face Seal ◽  
Air Flow Rate ◽  
The Difference ◽  
Air Film ◽  
Theoretical Results ◽  
Good Agreement

The sealing effects of squeeze air film were analyzed experimentally and theoretically. The air flow rate and the sealed pressure were measured in a squeeze face seal. The air flow rate can be expressed as the difference between the flow rate by the pumping and the flow rate by the leakage. The air flow rate by the pumping increases proportionally to the square of the vibration amplitude of the surface, as does the sealed pressure. The air flow rate by the leakage increases proportionally to the pressure difference between the vessel pressure and the ambient pressure. The experimental results showed good agreement with the theoretical results.

scholarly journals PENGARUH MODIFIKASI BACKCUT SEAT VALVE DAN UNDERCUTSTEM TERHADAP EFISIENSI VOLUMETRIK PADA CYLINDER HEAD MESIN ASTRO 108 CC

KOMPUTEK ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 13
Author(s):  
Aldi Prasetiyo ◽  
Sudarno Sudarno ◽  
Yoga Arob Wicaksono
Keyword(s):  
Flow Rate ◽  
Cylinder Head ◽  
Motor Vehicle ◽  
Air Flow ◽  
Volumetric Efficiency ◽  
Injection System ◽  
Fuel System ◽  
Air Flow Rate ◽  
Simple Modification ◽  
The Difference

As technology develops in the automotive world, more and more motor vehicle manufacturers are also applying the latest technologies, especially for vehicles sold in general. Call it, for example, the development of the fuel system, which was still a carburetor, now uses an injection system, from S.O.H.C to D.O.H.C. these technologies are useful for increasing volumetric efficiency. In this study, the researchers wanted to increase the volumetric efficiency of the Astro 108 cc engine by applying a simple modification, namely the inlet and exhaust that was modified with a 30 backcut on the valve, undercut system, and 4 angle valve jobs (30 , 45, 60 , 75 ). By applying these modifications to the Astro 108 cc engine, it can increase its volumetric efficiency, say at 2300 rpm with standard inlet and exhaust conditions producing an air flow rate of 0.000358 m3 / s and 0.000814 m3 / s, this data is obtained from pressure taking on the water box meter. The difference in flow occurs because the air that enters the inlet and exhaust is smoother due to the modifications made. With this flow rate, at 2300 rpm standard head produces a volumetric efficiency of 19.05712%, and 43.26364% with a modified head.

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Modeling and optimization of radish root extract drying as peroxidase source using spouted bed dryer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shahrbanoo Hamedi ◽  
M. Mehdi Afsahi ◽  
Ali Riahi-Madvar ◽  
Ali Mohebbi
Keyword(s):  
Kinetic Parameters ◽  
Flow Rate ◽  
Air Flow ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interactive Effects ◽  
Root Extract ◽  
Air Flow Rate ◽  
Spouted Bed ◽  
Radish Root

AbstractThe main advantages of the dried enzymes are the lower cost of storage and longer time of preservation for industrial applications. In this study, the spouted bed dryer was utilized for drying the garden radish (Raphanus sativus L.) root extract as a cost-effective source of the peroxidase enzyme. The response surface methodology (RSM) was used to evaluate the individual and interactive effects of main parameters (the inlet air temperature (T) and the ratio of air flow rate to the minimum spouting air flow rate (Q)) on the residual enzyme activity (REA). The maximum REA of 38.7% was obtained at T = 50 °C and Q = 1.4. To investigate the drying effect on the catalytic activity, the optimum reaction conditions (pH and temperature), as well as kinetic parameters, were investigated for the fresh and dried enzyme extracts (FEE and DEE). The obtained results showed that the optimum pH of DEE was decreased by 12.3% compared to FEE, while the optimum temperature of DEE compared to FEE increased by a factor of 85.7%. Moreover, kinetic parameters, thermal-stability, and shelf life of the enzyme were considerably improved after drying by the spouted bed. Overall, the results confirmed that a spouted bed reactor can be used as a promising method for drying heat-sensitive materials such as peroxidase enzyme.

Method to Determine an Optimal Air-Flow Rate in Solar Collectors

1979 ◽  
Vol 3 (6) ◽  
pp. 357-362
Author(s):  
H. C. Hewitt ◽  
E. I. Griggs
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Solar Collectors ◽  
Air Flow Rate

Model-Based Analysis of Transient Behavior of Large Scale CFB Boilers

2003 ◽  
Author(s):  
Ari Kettunen ◽  
Timo Hyppa¨nen ◽  
Ari-Pekka Kirkinen ◽  
Esa Maikkola
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Air Flow ◽  
Model Parameters ◽  
Air Flow Rate ◽  
Process Data ◽  
Cfb Boiler ◽  
Flow Rates ◽  
Load Change ◽  
Secondary Air

The main objective of this study was to investigate the load change capability and effect of the individual control variables, such as fuel, primary air and secondary air flow rates, on the dynamics of large-scale CFB boilers. The dynamics of the CFB process were examined by dynamic process tests and by simulation studies. A multi-faceted set of transient process tests were performed at a commercial 235 MWe CFB unit. Fuel reactivity and interaction between gas flow rates, solid concentration profiles and heat transfer were studied by step changes of the following controllable variables: fuel feed rate, primary air flow rate, secondary air flow rate and primary to secondary air flow ratio. Load change performance was tested using two different types of tests: open and closed loop load changes. A tailored dynamic simulator for the CFB boiler was built and fine-tuned by determining the model parameters and by validating the models of each process component against measured process data of the transient test program. The know-how about the boiler dynamics obtained from the model analysis and the developed CFB simulator were utilized in designing the control systems of three new 262 MWe CFB units, which are now under construction. Further, the simulator was applied for the control system development and transient analysis of the supercritical OTU CFB boiler.

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