Influence of secondary air mass flow rates on gas/particle flow characteristics near the swirl burner region

Energy ◽  
2011 ◽  
Vol 36 (5) ◽  
pp. 3599-3605 ◽  
Author(s):  
Jianping Jing ◽  
Zhengqi Li ◽  
Lin Wang ◽  
Lizhe Chen ◽  
Guohua Yang
Keyword(s):  
Mass Flow ◽  
Flow Characteristics ◽  
Particle Flow ◽  
Swirl Burner ◽  
Flow Rates ◽  
Air Mass ◽  
Mass Flow Rates ◽  
Secondary Air

An Experimental Study of the Flow of R-407C in an Adiabatic Spiral Capillary Tube

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
M. K. Mittal ◽  
R. Kumar ◽  
A. Gupta
Keyword(s):  
Experimental Data ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Tube ◽  
Flow Characteristics ◽  
Flow Rates ◽  
Tube Test ◽  
Mass Flow Rates ◽  
R 134A

The objective of this study is to investigate the effect of coiling on the flow characteristics of R-407C in an adiabatic spiral capillary tube. The characteristic coiling parameter for a spiral capillary tube is the coil pitch; hence, the effect of the coil pitch on the mass flow rate of R-407C was studied on several capillary tube test sections. It was observed that the coiling of the capillary tube significantly reduced the mass flow rate of R-407C in the adiabatic spiral capillary tube. In order to quantify the effect of coiling, the experiments were also conducted for straight a capillary tube, and it was observed that the coiling of the capillary tube reduced the mass flow rate in the spiral tube in the range of 9–18% as compared with that in the straight capillary tube. A generalized nondimensional correlation for the prediction of the mass flow rates of various refrigerants was developed for the straight capillary tube on the basis of the experimental data of R-407C of the present study, and the data of R-134a, R-22, and R-410A measured by other researchers. Additionally, a refrigerant-specific correlation for the spiral capillary was also proposed on the basis of the experimental data of R-407C of the present study.

Effect of Moisture Content on Mixing Air With Water-Liquid Flowing Through Inverted U-Tube for Power Plant Condenser Applications

2019 ◽  
Author(s):  
Khaled Yousef ◽  
Ahmed Hegazy ◽  
Abraham Engeda
Keyword(s):  
Water Vapor ◽  
Mass Flow ◽  
Static Pressure ◽  
Air Entrainment ◽  
Vapor Mixture ◽  
Flow Rates ◽  
Air Mass ◽  
Side Tube ◽  
Mass Flow Rates ◽  
Vapor Mass

Abstract Computational Fluid Dynamics (CFD) for air/water-vapor and water-liquid two-phase flow mixing with condensation in a vertical inverted U-tube is presented in this paper. This study is to investigate the flow behaviors and underlying some physical mechanisms encountered in air/water-vapor and water-liquid mixing flow when condensation is considered. Water-liquid flows upward-downward through the inverted U-tube while the air/water-vapor mixture is extracted from a side-tube just after the flow oriented downward. The CFD simulation is carried out for a side air/water-vapor mixture volume fraction (αm) of 0.2–0.7, water-vapor mass fraction (Xv) of 0.1–0.5 in the side air/water-vapor mixture and water-liquid mass flowrate (mw) of 2,4,6, and 8 kg/s. The present results reveal that, at lower air mass flow rate, no significant effect of Xv on the generated static pressure at the inverted U-tube higher part. However, by increasing the air mass flow rates, ma ≥ 0.001 at mw = 2 kg/s, and ma ≥ 0.00125 at mw = 4 kg/s, we can infer that the lowest static pressure can be attained at Xv = 0.1. This may be attributed to the increased vapor and air mass flow rates from the side tube which results in shifting the condensation from the tube highest part due to air accumulation. This leads to increasing the flow pressure and decelerating the water-liquid flow. Raising mw from 2 to 4 kg/s at the same vapor mass ratio results in a lower static pressure due to more condensation of water vapor. The turbulent intensity and kinetic energy starts to drop approximately at ma = 0.002 kg/s, and αm = 0.55–0.76 at mw = 2 kg/s for all Xv values but no noticeable change at mw = 4 kg/s occurs. These findings estimate the operational values of air and water mass flow rates for stable air entrainment from the side-tube. Increasing the air and vapor mass ratio over these values may block the evacuation process and fails the system continuance. Likewise more air entrainment from the side-tube will decelerate the water flow through the inverted U-tube and hence the flow velocity will decrease thereafter. Moreover, this study reveals that the inverted U-tube is able to generate a vacuum pressure down to 55.104 kPa for the present model when vapor condensation is considered. This generated low-pressure helps to vent an engineering system from the non-condensable gases and water vapor that fail its function if these are accumulated with time. Moreover, the water-liquid mass flow rate in the inverted U-tube can be used to sustain the required operating pressure for this system and extract the non-condensable gases with a less energy consuming system. The present CFD model provides a good physical understanding of the flow behavior for air/water-vapor and water-liquid flow for possible future application in the steam power plant.

Investigation of Flow Instabilities Near the Rim Cavity of a 1.5 Stage Gas Turbine

2009 ◽  
Author(s):  
M. Rabs ◽  
F.-K. Benra ◽  
H. J. Dohmen ◽  
O. Schneider
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Gas Turbines ◽  
Flow Instabilities ◽  
Navier Stokes ◽  
Flow Rates ◽  
Air Mass ◽  
Hot Gas ◽  
Path Modelling ◽  
Mass Flow Rates

The present paper gives a contribution to a better understanding of the flow at the rim and in the wheel space of gas turbines. Steady state and time-accurate numerical simulations with a commercial Navier-Stokes solver for a 1.5 stage turbine similar to the model treated in the European Research Project ICAS-GT were conducted. In the framework of a numerical analysis, a validation with experimental results of the test rig at the Technical University of Aachen will be given. In preceding numerical investigations of realistic gas turbine rim cavities with a simplified treatment of the hot gas path (modelling of the main flow path without blades and vanes), so called Kelvin-Helmholtz vortices were found in the area of the gap when using appropriate boundary conditions. The present work shows that these flow instabilities also occur in a 1.5 stage gas turbine model with consideration of the blades and vanes. Therefore, several simulations with different sealing air mass flow rates (CW 7000, 20000, 30000) have been conducted. The results show, that for high sealing air mass flow rates Kelvin-Helmholtz Instabilities are developing. These vortices significantly coin the flow at the rim.

Image Analysis of Particle Flow in Centrifugal Solar Particle Receiver

2021 ◽  
Author(s):  
Serdar Hicdurmaz ◽  
Reiner Buck ◽  
Bernhard Hoffschmidt
Keyword(s):  
Image Processing ◽  
Image Analysis ◽  
Numerical Model ◽  
Film Thickness ◽  
Flow Characteristics ◽  
Particle Flow ◽  
Flow Rates ◽  
Solar Particle ◽  
Stationary Zone ◽  
Mass Flow Rates

Abstract Particle solar receivers promise economical and operational advantages compared to the molten salt based solar receivers. In this study, an experiment is designed to observe the particle flow characteristics in the Centrifugal Solar Particle Receiver. A set of experiments for various receiver rotation speeds and particle mass flow rates is conducted, and experimentally obtained raw results are post-processed by means of an Image Processing Routine based on 4BestEstimate algorithm[1]. The axial advance of the particles in 1 turn, the particle film thickness and the ratio of the stationary zone to the receiver circumference are measured in order to be later used in the validation study of the Discrete Element Method based numerical model.

Design and analysis of bubble-injected water ramjets with discrete injection configurations by computational fluid dynamics method

2012 ◽  
Vol 227 (9) ◽  
pp. 1945-1955 ◽  
Author(s):  
Arash Nemati Hayati ◽  
Seyed Mohammad Hashemi ◽  
Mehrzad Shams
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mass Flow ◽  
Operating Conditions ◽  
Flow Rates ◽  
Air Mass ◽  
Mixing Chamber ◽  
Mass Flow Rates ◽  
Dynamics Method ◽  
Water Ramjet

In this study, the performance of a typical bubbly water ramjet was investigated by the application of computational fluid dynamics method at different vessel velocities up to 80 knots for a range of air mass flow rates up to 0.9 kg/s. For this purpose, the validity of presented method was preliminarily examined for a converging–diverging nozzle. Then, a designed ramjet with discrete injection configuration was studied at different operating conditions. It was proved that the injection process significantly increases the amount of generated thrust up to 10 times more than the thrust of a single-phase water ramjet. The results suggest that for optimum operation of the ramjet, specific values should be assigned for both inlet and mixing chamber diameters with respect to outlet diameter. Furthermore, it seems that the modification of mixing chamber profile can effectively improve the performance, as the generated thrust of model with throat-like chamber surpasses that for conventional model up to more than two times. Finally, in order to rectify the contradiction of results obtained in previous literatures on the dependency of thrust on vessel velocity, a meaningful relation was derived between the generated thrust of the ramjet with the advance velocity at different air mass flow rates.

A Comparison of a Mono, Twin and Double Scroll Turbine for Automotive Applications

2015 ◽  
Author(s):  
Jason Walkingshaw ◽  
Georgios Iosifidis ◽  
Tobias Scheuermann ◽  
Dietmar Filsinger ◽  
Nobuyuki Ikeya
Keyword(s):  
Mass Flow ◽  
Flow Characteristics ◽  
High Mass ◽  
Flow Rates ◽  
Engine Simulation ◽  
Engine Model ◽  
Trade Offs ◽  
Mass Flow Rates ◽  
The Individual ◽  
The Impact

As a means of meeting ever increasing emissions and fuel economy demands car manufacturers are using aggressive engine downsizing. To maintain the power output of the engine turbocharging is typically used. Due to the miss-match of the mass flow characteristics of the engine to the turbocharger, at low engine mass flow rates, the turbocharger can suffer from slow response known as “Turbolag”. Mono-scroll turbines are capable of providing good performance at high mass flow rates and in conjunction with low inertia mixed flow turbines can offer some benefits for transient engine response. With a multi-entry system the individual volute sizing can be matched to the single mass flow pulse from the engine cylinders. The exhaust pulse energy can be better utilised by the turbocharger turbine improving turbocharger response, while the interaction of the engine exhaust pulses can be better avoided, improving the scavenging of the engine. The behaviour of a mono-scroll turbocharger with the engine using engine simulation tools has been well established. What requires further investigation is the comparison with multi-entry turbines. CFD (Computational Fluid Dynamics) has been used to examine the single admission behaviour of a twin and double scroll turbine. Turbocharger gas stand maps of the multi-entry turbines have been measured at full and single admission. This data has been used in a 0D engine model. In addition, the turbine stage has been tested on the engine and a validation of the engine model against the engine test data is presented. Using the validated engine model a comparison has been made to understand the differences in the sizing requirements of the turbine and the interaction of the mono-scroll and multi-entry turbines with the engine. The impact of the different efficiency and mass flow rate trends of the mono and multi-entry turbochargers are discussed and the trade-offs between the design configurations regarding on engine behaviour are investigated.

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

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
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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