An Experimental Study of a “Once-Through” Thermosiphon System

An experimental study was conducted on the operation of a “once-through” thermosiphon system. This new type of natural circulation system, unlike the standard thermosiphon system, heats the collector fluid in one pass without any recirculation. An electrically heated manifold was used to simulate the useful solar gain. Power was varied with time in 22 half-hour increments to simulate the actual daily useful solar gain. The time-dependent responses of the system in terms of temperatures and mass flow rates were recorded and plotted. The response time for mass flow and temperature to approach steady state varied directly with the size of the power step. Two experiments were conducted; one which tracked mass flows and outlet temperatures for variable useful solar gains, and a second which tracked mass flows at constant outlet temperature for variable useful solar gains.

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Compressible Flow Ejectors: Part II—Flow Field Measurements and Analysis

Journal of Fluids Engineering ◽

10.1115/1.3447153 ◽

1974 ◽

Vol 96 (3) ◽

pp. 282-288 ◽

Cited By ~ 12

Author(s):

K. R. Hedges ◽

P. G. Hill

Keyword(s):

Experimental Study ◽

Mach Number ◽

Mass Flow ◽

Field Measurements ◽

Flow Ratio ◽

Flow Rates ◽

Jet Mixing ◽

Mass Flow Rates ◽

Exit Mach Number ◽

Mass Flow Ratio

An experimental study has been made of compressible jet mixing in an axisymmetric ejector of converging-diverging geometry. The mass flow ratio was in the range 1.3 to 2.6 and the nozzle exit Mach number was 1.82. Ejector performance characteristics were obtained as well as measurements of pressure and velocity distribution over a range of mass flow rates. The experimental results were used to test the reliability of the analytical model of the flow described in Part I of the paper.

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Effect of nozzle angle, turbine inlets and mass flow rate on the performance of a bladeless turbine

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650919893539 ◽

2019 ◽

Vol 234 (8) ◽

pp. 1101-1107

Author(s):

Muhammad Ali Kamran ◽

Shahryar Manzoor

Keyword(s):

Experimental Study ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Working Fluid ◽

Operating Parameters ◽

Lower Mass ◽

Flow Rates ◽

Significant Parameter ◽

Mass Flow Rates

A comprehensive experimental study on the effects of different operating parameters on the efficiency of tesla turbine is reported. A bladeless turbine with nine discs and up to four turbine inlets was used, with water as the working fluid. The parameters investigated are the nozzle angle, number of turbine inlets and mass flow rates. Contrary to earlier studies, an effort was made to determine the performance under varying loading conditions, and hence identify the complete performance characteristics. The study revealed that efficiency of the turbine increases at lower nozzle angles and higher number of turbine inlets. It was observed that the nozzle angle becomes a significant parameter when the number of turbine inlets is increased. Efficiencies up to 78% were achieved when the working fluid entered the turbine through two nozzles at an angle of 7°. It was also noted that the turbine is most efficient at the designed mass flow rate, and the efficiency reduces appreciably if lower mass flow rates are fed to the turbine. The results obtained are an important contribution to the available knowledge and can be used as design references for further studies.

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Performance Analysis of Air and Oxy-Fuel Laminar Combustion in a Porous Plate Reactor

Energies ◽

10.3390/en12091706 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1706

Author(s):

Furqan Tahir ◽

Haider Ali ◽

Ahmer A.B. Baloch ◽

Yasir Jamil

Keyword(s):

Mass Flow ◽

Carbon Capture ◽

Numerical Study ◽

Porous Plate ◽

Flame Temperature ◽

Fuel Combustion ◽

Mitigation Measures ◽

Outlet Temperature ◽

Flow Rates ◽

Mass Flow Rates

Greenhouse gas emissions from the combustion of fossil fuels pose a serious threat to global warming. Mitigation measures to counter the exponential growth and harmful impact of these gases on the environment require techniques for the reduction and capturing of carbon. Oxy-fuel combustion is one such effective method, which is used for the carbon capture. In the present work, a numerical study was carried out to analyze characteristics of oxy-fuel combustion inside a porous plate reactor. The advantage of incorporating porous plates is to control local oxy-fuel ratio and to avoid hot spots inside the reactor. A modified two-steps reaction kinetics model was incorporated in the simulation for modeling of methane air-combustion and oxy-fuel combustion. Simulations were performed for different oxidizer ratios, mass flow rates, and reactor heights. Results showed that that oxy-combustion with an oxidizer ratio (OR) of 0.243 could have the same adiabatic flame temperature as that of air-combustion. It was found that not only does OR need to be changed, but also flow field or reactor dimensions should be changed to achieve similar combustion characteristics as that of air-combustion. Fifty percent higher mass flow rates or 40% reduction in reactor height may achieve comparable outlet temperature to air-combustion. It was concluded that not only does the oxidizer ratio of oxy-combustion need to be changed, but the velocity field is also required to be matched with air-combustion to attain similar outlet temperature.

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Experimental Study of the Slit Spacing and Bed Height on the Thermal Performance of Slit-Glazed Solar Air Heater

International Journal of Photoenergy ◽

10.1155/2017/9851376 ◽

2017 ◽

Vol 2017 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Seyyed Mahdi Taheri Mousavi ◽

Fuat Egelioglu

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Ambient Air ◽

Solar Air Heater ◽

Outlet Temperature ◽

Flow Rates ◽

Air Mass ◽

Bed Height ◽

Mass Flow Rates

The thermal performances of three slit-glazed solar air heaters (SGSAHs) were investigated experimentally. Three SGSAHs with different bed heights (7 cm, 5 cm, and 3 cm) were fabricated with multiple glass panes used for glazing. The length, width, and thickness of each pane were 154 cm, 6 cm, and 0.4 cm, respectively. Ambient air was continuously withdrawn through the gaps between the glass panes by fans. The experiments were conducted for four different gap distances between the glass panes (0.5 mm, 1 mm, 2 mm, and 3 mm) and the air mass flow rate was varied between 0.014 kg/s and 0.057 kg/s. The effects of air mass flux on the outlet temperature and thermal efficiency were studied. For the SGSAH with bed height of 7 cm and glass pane gap distance of 0.5 mm, the highest efficiency was obtained as 82% at a mass flow rate of 0.057 kg/s and the air temperature difference between the inlet and the outlet (∆T) was maximum (27°C) when the mass flow rate was least. The results demonstrate that for lower mass flow rates and larger gaps, the performance of SGSAH with a bed height of 3 cm was better compared to that of others. However, for higher mass flow rates, the SGSAH with 7 cm bed height performed better.

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ŠILUMNEŠIO DEBITO ĮTAKOS FAZINIO VIRSMO MEDŽIAGOS VEIKIMUI TYRIMAS / INVESTIGATION OF THE INFLUENCE OF MASS FLOW RATE ON PHASE CHANGE MATERIAL BEHAVIOUR

Mokslas - Lietuvos ateitis ◽

10.3846/mla.2019.10578 ◽

2019 ◽

Vol 11 (0) ◽

pp. 1-5 ◽

Cited By ~ 1

Author(s):

Saulius Pakalka ◽

Kęstutis Valančius ◽

Matas Damonskis

Keyword(s):

Experimental Study ◽

Phase Change ◽

Mass Flow Rate ◽

Phase Change Material ◽

Mass Flow ◽

Flow Rate ◽

Heat Transfer Fluid ◽

Flow Rates ◽

Mass Flow Rates ◽

Change Material

The paper presents an experimental study of the influence of heat transfer fluid (HTF) mass flow rate on phase change materials (PCM) behaviour. The experimental study was performed on a specially designed test bench. Research object – PCM based thermal energy storage unit which consists of a stainless steel tank with dual circuit tube-fin copper heat exchanger. The tank (storage volume) was filled with phase change material RT82. The experiment was carried out using three different mass flow rates of HTF: high – 0.25 kg/s, medium – 0.125 kg/s, low – 0.05 kg/s. The analysis showed that in the case of high and medium mass flow rates the melting/solidification process highly depends on the temperature of inlet HTF. Influence of mass flow rate is higher in the case of low mass flow rate.

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Experimental study of solar thermal systems with Al2O3 / water nanofluids and efficiency with different tape inserts and different mass flow rates with fixed volume concentration

Journal of Chemical Biological and Physical Sciences ◽

10.24214/jcbps.c.10.3.13865 ◽

2020 ◽

Vol 10 (3) ◽

Keyword(s):

Experimental Study ◽

Mass Flow ◽

Volume Concentration ◽

Solar Thermal ◽

Thermal Systems ◽

Flow Rates ◽

Fixed Volume ◽

Mass Flow Rates

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Calibration of a V-Cone for Low Mass Flows for Small Core Compressor Research

Volume 2A: Turbomachinery ◽

10.1115/gt2020-16104 ◽

2020 ◽

Author(s):

Julia E. Stephens ◽

Sameer Kulkarni

Keyword(s):

Mass Flow ◽

High Speed ◽

Pressure Ratio ◽

Axial Compressor ◽

Flow Rates ◽

Turbofan Engines ◽

Mass Flow Rates ◽

Low Mass ◽

Mass Flows ◽

Multistage Axial Compressor

Abstract Advancements in core compressor technologies are necessary for next generation, high Overall Pressure Ratio (OPR) turbofan engines. High pressure compressors (HPCs) for future engines are being designed with exit corrected mass flow rates less than 2.25 kg/s (5 lbm/s). In order to accurately measure the performance of these advanced designs, high accuracy measurements are needed in test facilities. The W7 High Speed Multistage Axial Compressor Facility at NASA Glenn Research Center has been used to acquire data for advanced compressor designs. This facility utilizes an advanced differential pressure flow meter called a V-Cone. The facility has historically tested components with physical mass flow rates in the range of 27 to 45 kg/s (60 to 100 lbm/s). As such, when the V-Cone was calibrated prior to installation, the calibrations focused on higher mass flow rates, and uncertainties in that regime range from 0.5% to 0.85%. However, for low mass flow rates under 9 kg/s (20 lbm/s), expected in tests of advanced high OPR HPCs rear stages, the uncertainties of the V-Cone exceed 2.5%. To address this, using a method similar to that utilized by the National Institute of Standards and Technology, an array of Critical Flow Venturi Nozzles (CFVs) was installed in the W7 test section and used to calibrate the V-Cone in 0.5 kg/s (1 lbm/s) increments up to 10.5 kg/s (23 lbm/s). This effort details the measurements and uncertainties associated with this calibration which resulted in a final uncertainty of the V-Cone measurements under 1%.

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Experimental Study of the Diversion Crossflow Caused by Subchannel Blockages. Part I: Experimental Procedures and Mass Flow Rates in the Channels

Journal of Fluids Engineering ◽

10.1115/1.3243143 ◽

1984 ◽

Vol 106 (4) ◽

pp. 435-440 ◽

Cited By ~ 8

Author(s):

S. Genc¸ay ◽

A. Tapucu ◽

N. Troche ◽

M. Merilo

Keyword(s):

Experimental Study ◽

Mass Flow ◽

Short Distance ◽

Cross Flow ◽

Geometric Parameters ◽

Slow Process ◽

Hydrodynamic Behavior ◽

Flow Rates ◽

Mass Flow Rates ◽

Different Shapes

In this research, the hydrodynamic behavior of two laterally interconnected channels with blockages in one of them has been studied experimentally. For blockages of different shapes and severities, the mass flow rates as well as the pressures in the channels upstream and downstream of the blockage were determined. The experiments were conducted on a test sections which consists of two-square channels separated by an intermediate plate with slots of different geometric parameters. Two types of blockages have been considered: plate and smooth. The shape of the smooth blockage was a cosine. In the region upstream of the blockage, the diversion cross-flow takes place over a relatively short distance. Downstream of the blockage, the recovery of the diverted flow by the blocked channel is a slow process and the rate of this recovery worsens with increasing blockage severity. For a given blockage rate, the diversion crossflow caused by a smooth blockage is smaller than that of a plate blockage.

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