scholarly journals Parametric Study on the Flow Profiles of Vertical Sinter Cooling Bed Using the DEM and Taguchi Method for Waste Heat Recovery

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5030
Author(s):  
Junpeng Fu ◽  
Jiuju Cai
Keyword(s):  
Aspect Ratio ◽  
Taguchi Method ◽  
Waste Heat ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
External Factors ◽  
Influential Factor ◽  
Geometry Factor ◽  
Discharge Velocity ◽  
Performance Of Heat Transfer

To comprehensively understand the effectiveness of external factors on flow characteristics and realize particle flow distribution evenly in bulk layers is an essential prerequisite for improving the performance of heat transfer in vertical sinter cooling beds (VSCBs). The numerical discrete element method (DEM) was applied to investigate external geometric and operational factors, such as the aspect ratio, geometry factor, half hopper angle, normalized outlet scale, and discharge velocity. Using the Taguchi method, a statistical analysis of the effect of design factors on response was performed. In this study, we focused more on external factors than granular properties, be remodelling the external factors was more useful and reliable for actual production in industries. The results showed that the most important factor was the aspect ratio, followed by the geometry factor, normalized outlet scale, half hopper angle, and discharge velocity for the dimensionless height of mass flow. In terms of the Froude number, the most influential factor was the normalized outlet scale with a contribution ratio of 33.81%, followed by the aspect ratio (22.86%), geometry factor (17.73%), discharge velocity (17.73%), and half hopper angle (11.83%).

scholarly journals Simulation Study on Active Air Flow Distribution Characteristics of Closed Heat Pump Drying System with Waste Heat Recovery

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6358
Author(s):  
Hai-Bo Zhao ◽  
Kun Wu ◽  
Jing-Feng Zhang
Keyword(s):  
Heat Pump ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Air Flow ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Drying System ◽  
Heat Pump Drying ◽  
Active Flow

A tridimensional turbulent flow model is established for a closed heat pump drying system with waste heat recovery to improve the drying air flow characteristics and reduce the energy consumption of air circulation. The active flow distribution mode is introduced to guide air flowing in the system’s drying cabinet, top air duct, mixing zone, and heat pump. It is found that the wind velocity in the cabinet’s supply channel is greater than that in the return channel, the velocity distribution in the top duct is uneven, and the outlet velocity of the bypass fan is high and a vortex forms. A partition panel added in the top duct and modulating fans in the drying cabinet are proposed to solve these problems. The simulation results show that removing the circulating fan, changing the volume flow of the bypass fan, adopting the alternative operation mode of the bypass fans, reducing the air volume flow of the supply fan, and reducing the total pressure of the fans can improve the dry air velocity uniformity in the drying cabinet and reduce the energy consumption of the fans. This paper analyzes the closed-loop drying air flow characteristics of the active flow distribution system in the heat pump drying system, which lays a foundation for the wind velocity, temperature, and humidity regulating of heat pump drying system with waste heat recovery.

scholarly journals Modelling of service reservoirs

2001 ◽  
Vol 3 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Hoi Yeung
Keyword(s):  
Plug Flow ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Tracer Test ◽  
Computational Fluid Mechanics ◽  
Width Ratio ◽  
Dual Function ◽  
Water Age ◽  
Reactor Model ◽  
Increased Risk

Service reservoirs were built to provide the dual function of balancing supply with demand and provision of adequate head to maintain pressure throughout the distribution network. Changing demographics in the UK and reducing leakage have led to significant increases in water age and hence increased risk of poor water quality. Computational fluid mechanics has been used to study the behaviour of a range of service reservoirs with a rectangular plan form. Detailed analysis of flow distribution and water age suggests that tanks with horizontal inlets are better mixed when compared with vertical top water level inlets. With increasing length to width ratio, the flow characteristics of tanks with vertical inlets increasingly resemble plug flow. A new multi-channel reactor model was developed to model the recirculations in service reservoirs. This simple model can be used to characterise the flow characteristics of service reservoirs from tracer test results.

Qualitative Diagnosis of Solid Breast Mass by Blood Flow in Solid Breast Mass Based on Color Doppler Ultrasound

2021 ◽  
Vol 11 (6) ◽  
pp. 1608-1615
Author(s):  
Ding Zuopeng ◽  
Liu Weiyong ◽  
Hu Chunmei ◽  
Wang Tao ◽  
Wang Mingming
Keyword(s):  
Breast Cancer ◽  
Blood Flow ◽  
Differential Diagnosis ◽  
Color Doppler ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Color Doppler Ultrasound ◽  
Blood Flow Distribution ◽  
Breast Masses ◽  
Malignant Breast

The incidence of breast cancer ranks first among female malignant tumor. With the increase of the sensitivity of color Doppler ultrasound blood flow, the blood flow distribution in and around the tumor can be clearly displayed, and the analysis of hemodynamic parameters is provided, which provides convenience for the study of tumor blood flow characteristics. Studies have shown that tumor cells can secrete a substance called angiogenesis factor, which makes the tumor site form a rich vascular network to promote tumor growth and metastasis. The tumor has many new blood vessels, abnormal structure, thin wall, lack of muscle layer, and is prone to form arteriovenous rash. These characteristics provide a pathological basis for color Doppler flow imaging (CDFI) for the diagnosis of breast cancer. This article discusses the role of two-dimensional sonographic features in the differential diagnosis of benign and malignant breast masses, CDFI was used to study the blood flow distribution and hemodynamic characteristics in benign and malignant breast masses; explore the value of blood flow characteristics and blood flow parameters in the differential diagnosis of breast masses. The experimental results show that the detection rate of blood flow signals and the classification of blood flow signals in the malignant group are higher than those in the benign group, mainly level II and III blood flow, and the irregular branched blood flow is more common, especially when the tumor appears penetrating blood flow supports the diagnosis of malignancy. PSV, RI and PI have a certain differential meaning in the diagnosis of benign and malignant breast masses. PSV, RI and PI of malignant masses are higher than benign masses. For tumors without obvious necrosis, the larger the tumor diameter, the richer the blood flow and the higher the blood flow grade is. The malignant tumors have more blood flow than the benign ones.

CFD Study on the Flow Characteristics in Filleted Microchannels

2011 ◽  
Vol 103 ◽  
pp. 268-273
Author(s):  
Hong Jie Yan ◽  
Ping Zhou ◽  
Ze Lin Xu ◽  
Zhuo Chen ◽  
Jing Wen Mo
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Flow Model ◽  
Constant Width ◽  
Flow Characteristics ◽  
Flow Pressure ◽  
Cfd Method ◽  
Poiseuille Number ◽  
The Relationship ◽  
Laminar Flow Model

The flow characteristics of water in filleted microchannels were simulated based on CFD method. The flow pressure drop at different aspect ratioandRenumber were rearranged on the simulating results with laminar flow model. The results indicated that the pressure drop enlarges with the increase of in the case of the constant width of the microchannel. Within the range ofRenumber of interest, Poiseuille number of the flow is constant for differentRe, but decreases with increasing aspect ratio. An equation was fitted to describe the relationship betweenPonumber and aspect ratio, i.e. .

scholarly journals Swirling Flows Characteristics in a Cylinder Under Effect of Buoyancy

Mechanika ◽  
2021 ◽  
Vol 27 (3) ◽  
pp. 201-208
Author(s):  
Mustafa FEKHAR ◽  
Rachid SACI ◽  
Renée GATIGNOL
Keyword(s):  
Aspect Ratio ◽  
Thermal Stratification ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Swirling Flows ◽  
Viscous Effects ◽  
Thermal Buoyancy ◽  
State Diagrams ◽  
The Core ◽  
Flow Stagnation

Thermal buoyancy, induced by injection or by differential heating of a tiny rod is explored to control breakdown in the core of a helical flow driven by the lid rotation of a cylinder. Three main parameters are required to characterize numerically the flow behavior; namely, the rotational Reynolds number Re, the cavity aspect ratio and the Richardson number Ri. Warm injection/rod, Ri > 0, is shown to prevent on-axis flow stagnation while breakdown enhancement is evidenced when Ri < 0. Results revealed that a bubble vortex evolves into a ring type structure which may remain robust, as observed in prior related experiments or, in contrast, disappear over a given range of parameters (Λh, Re, Ri > 0). Besides, the emergence of such a toroidal mode was not found to occur under thermal stratification induced by a differentially heated rod. Moreover, three state diagrams were established which provide detailed flow characteristics under the distinct and combined effects of buoyancy strength, viscous effects and cavity aspect ratio.

Diesel Spray Rate-of-Momentum Measurement Uncertainties and Diagnostic Considerations

2014 ◽  
Author(s):  
Benjamin W. Knox ◽  
Michael J. Franze ◽  
Caroline L. Genzale
Keyword(s):  
Force Measurement ◽  
Control Volume ◽  
Flow Characteristics ◽  
Fuel Temperature ◽  
Integrated Electronics ◽  
Injector Nozzle ◽  
Fuel Delivery ◽  
Discharge Velocity ◽  
The Face ◽  
Measurement Uncertainties

Interpretation of combustion and emissions outcomes in diesel engines is often enhanced by accurate knowledge of the transient fuel delivery rate and flow characteristics of the injector nozzle. Important physical characteristics of these flows, including velocity profile and flow separation or cavitation effects, are difficult to measure directly, but can be characterized from a flow-averaged perspective through the measurement of nozzle flow coefficients, namely the discharge, velocity, and area contraction coefficients. Both the transient fuel mass flow rate and the flow-averaged nozzle coefficients can be found by measuring the mass and momentum flux of the fuel stream leaving the nozzle during injection through the application of an impingement technique, where fuel is sprayed onto the face of a transducer calibrated for force measurement in close proximity to the nozzle. While several published experiments have employed the spray impingement method to quantify rate-of-injection, the experimental setup and equipment selections vary widely and may contribute to disagreements in measured rate-of-injection. This paper identifies and provides estimates of measurement uncertainties that can arise when employing different experimental setups using the impingement method. It was observed that the impingement technique was sensitive to the design of the strike cap, specifically the contact area between the cap and transducer diaphragm, in addition to fuel temperature. Conversely, we observed that the impingement technique was relatively insensitive to angular and vertical misalignment, where the uncertainty can be estimated using control volume analysis. Transducer selection, specifically those with low acceleration sensitivity, high resonant frequency, and integrated electronics piezoelectric circuitry substantially reduce the noise in the measurement.

Flow Distribution and Slug Flow Characteristics for Hydraulically Equilibrium Air-Water Two-Phase Flows in a Vertical 2×3 Rod Channel

2003 ◽  
Author(s):  
Keiko Kano ◽  
Michio Sadatomi ◽  
Akimaro Kawahara ◽  
Tsukasa Kuno
Keyword(s):  
Flow Characteristics ◽  
Prediction Method ◽  
Flow Distribution ◽  
Bubble Velocity ◽  
Accurate Estimation ◽  
Two Phase ◽  
Taylor Bubble ◽  
Rod Bundle ◽  
Superficial Gas Velocity ◽  
Churn Flow

To complete subchannel analysis for predicting thermal-hydraulic behavior of coolant in a BWR rod bundle channel, accurate estimation of fluid transfer between subchannels is necessary. In order to validate a prediction method, flow distributions data of gas and liquid phases are essential. But, such data reported so far are limited to those in a two-subchannel system alone. Then we have measured flow distributions of both phases and Taylor bubble velocity in a multi-subchannel system as called 2×3 rod bundle channel. It has been found that flow distributions of gas and liquid in bubble and annular flows under a hydraulically equilibrium flow condition are close to those of single-phase flow, but in slug-churn flow the distributions are different. In slug-churn flow, both superficial gas velocity and Taylor bubble velocity are higher in larger subchannel. These experimental data are presented and discussed in this paper.

Numerical Simulation of the Temperature Field and the Flow Field Inside the Domestic Cooling and Heating Unit’s Water Tank

2012 ◽  
Author(s):  
Chao Zhu ◽  
Mo Yang ◽  
Yuwen Zhang ◽  
Jinlong Wang
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Flow Field ◽  
Water Temperature ◽  
Waste Heat ◽  
Flow Distribution ◽  
Water Tank ◽  
Heating Unit ◽  
Speed Up

A water tank of the domestic cooling and heating unit, which has a helix coil, is used to recover the waste heat of the unit. The temperature field and the flow field in the water tank have great effects on the variation of the water temperature in it. In order to obtain the temperature distribution, the flow distribution and the influencing factors, and then obtain the changing situation of the water temperature, the temperature field and the flow field of the water tank are simulated by using Fluent. The results showed that the water temperature will change with different coil decorate. The numerical model which is created by Fluent is appropriate and could be used to improve the layout of the coil in the water tank and speed up heating.

Sign in / Sign up

Export Citation Format

Share Document