Design and Numerical Analysis of a Vane Shaped Receiver Hole in a Cover-Plate Preswirl System

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Yuxin Liu ◽  
Gaowen Liu ◽  
Xiaozhi Kong ◽  
Yangang Wang
Keyword(s):  
Temperature Drop ◽  
Operating Conditions ◽  
Cover Plate ◽  
Cooling Performance ◽  
Aerodynamic Loss ◽  
Low Leakage ◽  
System A ◽  
New Type ◽  
Model C ◽  
Plate System

In a cover-plate system, rotating receiver hole is an important component, because its structure and characteristics directly influence the aerodynamic loss and cooling performance in the preswirl system. A new type of vane shaped (VS) receiver hole was designed and presented in this paper. Numerical simulations were carried out to compare the performances among high-radius direct transfer system (model-A), low-radius cover-plate system with simple drilled (SD) receiver holes (model-B), and low-radius cover-plate system with VS receiver holes (model-C). Results indicate that for the operating conditions simulated here, temperature drop effectiveness of the high-radius preswirl system is much better compared to the low-radius system with SD receiver hole. With VS receiver hole, the aerodynamic loss in model-C is the lowest. The nondimensional static pressure at preswirl nozzle exit is only 0.93, around 10% lower than model-B. Moreover, it has a more remarkable cooling performance. The temperature drop effectiveness of model-C can be as high as 0.52, around 67.7% higher compared to model-A. The system with VS receiver hole could not only realize the advantage of low leakage flow as a low-radius system, but also could achieve higher temperature drop compared to high-radius system.

Remote Heat Pipe Based Heat Exchanger Performance in Notebook Cooling

2005 ◽  
Author(s):  
Seyyed Khandani ◽  
Himanshu Pokharna ◽  
Sridhar Machiroutu ◽  
Eric DiStefano
Keyword(s):  
Heat Exchanger ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Cooling System ◽  
Temperature Drop ◽  
Operating Conditions ◽  
Cooling Systems ◽  
Temperature Variations ◽  
Non Linear ◽  
Condenser Temperature

Remote heat pipe based heat exchanger cooling systems are becoming increasingly popular in cooling of notebook computers. In such cooling systems, one or more heat pipes transfer the heat from the more populated area to a location with sufficient space allowing the use of a heat exchanger for removal of the heat from the system. In analsysis of such systems, the temperature drop in the condenser section of the heat pipe is assumed negligible due to the nature of the condensation process. However, in testing of various systems, non linear longitudinal temperature drops in the heat pipe in the range of 2 to 15 °C, for different processor power and heat exchanger airflow, have been measured. Such temperature drops could cause higher condenser thermal resistance and result in lower overall heat exchanger performance. In fact the application of the conventional method of estimating the thermal performance, which does not consider such a nonlinear temperature variations, results in inaccurate design of the cooling system and requires unnecessarily higher safety factors to compensate for this inaccuracy. To address the problem, this paper offers a new analytical approach for modeling the heat pipe based heat exchanger performance under various operating conditions. The method can be used with any arbitrary condenser temperature variations. The results of the model show significant increase in heat exchanger thermal resistance when considering a non linear condenser temperature drop. The experimental data also verifies the result of the model with sufficient accuracy and therefore validates the application of this model in estimating the performance of these systems.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.

Agglomeration Technologies of Processing Powder Wastes

2015 ◽  
Vol 244 ◽  
pp. 121-129
Author(s):  
Marian Peciar ◽  
Roman Fekete ◽  
Peter Peciar
Keyword(s):  
Research Work ◽  
Operating Conditions ◽  
Airborne Particles ◽  
Raw Material ◽  
Production Cycle ◽  
Shear Forces ◽  
Material Resources ◽  
New Type ◽  
Two Phases ◽  
High Technologies

This article deals with the presentation of modern applications for processing powdered, primarily hazardous, waste to an agglomeration form appropriate for subsequent processing by classical methods, for example in the construction, automotive and consumer goods industries. The aim of the research work was to set appropriate operating conditions in order to appreciate currently non-processable wastes resulting from the intensive production of often extremely expensive materials. Technologies which enable returning powder waste back into the primary production cycle were developed and experimentally tested, thus saving raw material resources. When necessary for the fixing of fine airborne particles with a problematic compacting curve (hard to compress, repulsive due to the surface charge) extrusion processes using a patented technology enabling controlled modification of shear forces in the extrusion zone were successfully applied. A new type of axial extruder allows the elimination of the liquid phase and as a result prevents the clogging of the extrusion chamber. In the case of need for granulation of sensitive materials (for example pharmaceuticals not allowing the addition of any kind of agglomerating fluid or reacting strongly in the contact of the two phases), a process of compaction between rolls with different profiled surface was successfully applied. The developed high technologies and the resulting products thus represent a major contribution to environmental protection in the context of not only the work but also the communal environment.

Design of an Air-Cooled Radial Turbine: Part 1 — Computational Modelling

2018 ◽  
Author(s):  
Yang Zhang ◽  
Tomasz Duda ◽  
James A. Scobie ◽  
Carl M. Sangan ◽  
Colin D. Copeland ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Experimental Testing ◽  
Temperature Drop ◽  
Computational Modelling ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Topology Optimisation ◽  
Internal Cooling ◽  
Element Analysis ◽  
Radial Turbine

This paper is part of a two-part publication that aims to design, simulate and test an internally air cooled radial turbine. To achieve this, the additive manufacturing process, Selective Laser Melting (SLM), was utilized to allow internal cooling passages within the blades and hub. This is, to the authors’ knowledge, the first publication in the open literature to demonstrate an SLM manufactured, cooled concept applied to a small radial turbine. In this paper, the internally cooled radial turbine was investigated using a Conjugate Heat Transfer (CHT) numerical simulation. Topology Optimisation was also implemented to understand the areas of the wheel that could be used safely for cooling. In addition, the aerodynamic loss and efficiency of the design was compared to a baseline non-cooled wheel. The experimental work is detailed in Part 2 of this two-part publication. Given that the aim was to test the rotor under representative operating conditions, the material properties were provided by the SLM technology collaborator. The boundary conditions for the numerical simulation were derived from the experimental testing where the inlet temperature was set to 1023 K. A polyhedral unstructured mesh made the meshing of internal coolant plenums including the detailed supporting structures possible. The simulation demonstrated that the highest temperature at the blade leading edge was 117 K lower than the uncooled turbine. The coolant mass flow required by turbine was 2.5% of the mainstream flow to achieve this temperature drop. The inertia of the turbine was also reduced by 20% due to the removal of mass required for the internal coolant plenums. The fluid fields in both the coolant channels and downstream of the cooled rotor were analyzed to determine the aerodynamic influence on the temperature distribution. Furthermore, the solid stress distribution inside the rotor was analyzed using Finite Element Analysis (FEA) coupled with the CFD results.

scholarly journals Determining the environmental indicators for vehicles of different categories in relation to CO2 emission based on road tests

2017 ◽  
Vol 170 (3) ◽  
pp. 66-72
Author(s):  
Jerzy MERKISZ ◽  
Łukasz RYMANIAK
Keyword(s):  
Co2 Emissions ◽  
Operating Time ◽  
Environmental Indicators ◽  
Operating Conditions ◽  
Si Engine ◽  
Propulsion Systems ◽  
System A ◽  
In Series ◽  
Series Configuration ◽  
Ci Engine

The article discusses the possibility of determining the environmental indicators for vehicles of different categories in relation to CO2 emissions. These are called toxicity indicators because they concern the compounds: CO, THC and NOx. Three Euro V compliant vehicles with different propulsion systems types were used for the study: a 0.9 dm3 urban passenger car with a SI engine and a start-stop system, a 2.5 dm3 off-road vehicle with a CI engine, and a city bus with a hybrid drive system in series configuration and a CI engine with a displacement of 6.7 dm3. Measurements were made in actual operating conditions in the Poznan agglomeration using a portable emissions measurement system (PEMS). The paper presents the characteristics of the operating time shares of vehicles and propulsion systems as well as CO2 emissions depending on the engine load and crankshaft rotational speed for individual vehicles. The determined toxicity indicators allowed to indicate their usefulness, to make comparisons between tested vehicles, and to identify directions for further work on the application and interpretation of these indicators.

scholarly journals PROFESSIONAL RISKS TO HEALTH OF THE PERSONNEL OF EXIT BRIGADES OF SERVICE OF THE FIRST HELP

2021 ◽  
Vol 21 (4) ◽  
pp. 17-23
Author(s):  
V. O. Krasovskij ◽  
L. M. Karamova ◽  
G. R. Basharova
Keyword(s):  
Operating Conditions ◽  
Muscular System ◽  
System A ◽  
The Given

Clause analyzes the reasons of professional risks for health of the personnel of exit brigades of the first help. Clinical and hygienic researches in regional substation of a megacity have shown that in labour activity of these workers it is necessary to consider as leading professional harm action of transport vibration. The given circumstance and other reasons provide professional risks of development of illnesses of cardiovascular, bone-muscular system, a gastroenteric path. The interdepartmental complex of actions on improvement of operating conditions of the exit personnel is offered.

scholarly journals Plea Bargaining Changing Nordic Criminal Procedure: Sweden and Finland as Examples

2021 ◽  
pp. 255-269
Author(s):  
Laura Ervo
Keyword(s):  
Conflict Resolution ◽  
Procedural Justice ◽  
Plea Bargaining ◽  
Legal Culture ◽  
European Countries ◽  
Court Culture ◽  
Criminal Proceedings ◽  
System A ◽  
Northern European ◽  
New Type

AbstractA plea bargaining system is a novelty and originally a legal transplant in Northern European countries. It exists—in some form—for instance in Finland, Norway and Denmark, whereas in Sweden only the system of crown witnesses is likely to be introduced. In this chapter plea bargaining is put into the East-Nordic—Finnish and Swedish—contexts. How does plea bargaining fit into the East-Nordic court culture? Which ingredients does the contemporary legal culture consist of? In which way is court culture changing due to the new values in the society? Or are the amendments made primarily to reduce the costs of the state? Fairness, procedural justice, conflict resolution, negotiated law, pragmatically acceptable compromise, procedural truth, court service, communication and interaction are examples of the topics that are currently discussed in Finland and Sweden. At the same time, the use of written proceedings and proceedings in the absence of an accused are increasing. Is the plea bargaining system a step towards a more effective and economic criminal procedural system or is it mirroring new type of thinking concerning criminal proceedings? In this chapter, these elements are discussed. Finland is used as a main example. The Finnish situation is also compared with Sweden.

Mill experience of calcium carbonate scale formation in green liquor pipelines

TAPPI Journal ◽  
2020 ◽  
Vol 19 (8) ◽  
pp. 387-397
Author(s):  
ALISHA GIGLIO ◽  
HONGHI TRAN ◽  
MARIA BJORK ◽  
RICKARD WADSBORN ◽  
HAL LAGIMODIERE ◽  
...  
Keyword(s):  
Kraft Pulp ◽  
Temperature Drop ◽  
Metal Substrate ◽  
Scale Formation ◽  
Operating Conditions ◽  
Pulp Mills ◽  
Green Liquor ◽  
Kraft Pulp Mills ◽  
High Degree ◽  
Calcium Carbonate Scale

Experience of hard calcite (CaCO3) scale formation in green liquor pipelines at four kraft pulp mills was systematically investigated to determine if there is any correlation between the severity of the scaling problem at each mill and the design and operating conditions of its causticizing plant. The results show that the high degree of supersaturation of calcium ions (Ca2+) in the liquor is the main contributing factor. Mills that operate at a lower green liquor total titratable alkali (TTA), higher causticity, and a larger liquor temperature drop are more likely to pro-duce a green liquor that is supersaturated with Ca2+, and thus experience more severe scaling problems. In order to minimize CaCO3 scaling, the green liquor handling equipment should be operated as steady as possible to avoid conditions that allow Ca2+ to be supersaturated. The strategies include minimizing variations in liquor TTA, insulating the green liquor pipelines to reduce temperature gradients, and adding lime mud to weak wash to provide seeds for precipitation to occur on mud particles instead of on metal substrate.

scholarly journals CFD Simulation Research on Agglomeration between Coal-fired Ash Fine Particulate and Atomized Droplets

2020 ◽  
Vol 165 ◽  
pp. 01006
Author(s):  
Yiquan Guo ◽  
Junying Zhang
Keyword(s):  
Power Plant ◽  
Flow Field ◽  
Cfd Simulation ◽  
Negative Impact ◽  
Droplet Diameter ◽  
Temperature Drop ◽  
Operating Conditions ◽  
Gas Temperature ◽  
Simulation Research ◽  
Agglomeration Process

In this paper, a collision model between atomized droplets of agglomeration solution and particles is established. On this basis, the effects of flue gas temperature, atomized droplet diameter and other factors on the particle agglomeration process are studied. In addition, the evaporation model of agglomeration solution in the flue of a power plant is established for the coal-fired unit of power plant. Through CFD software, the variation of flow field velocity, temperature and pressure in the flue is simulated to determine whether the chemical agglomeration technology has negative impact on the actual operating conditions of the power plant. The simulation results show that the velocity and pressure of the flow field in the flue have no obvious change after the agglomerating agent is injected. Besides, the temperature drop of about 7°C. The droplets evaporate completely at a distance of 7-8 m after spraying. The evaporation time of droplets is within 1.6 s.

Experimental and numerical investigation on the vertical bearing behavior of discrete connected new-type precast reinforced concrete floor system

2020 ◽  
Vol 23 (11) ◽  
pp. 2276-2291
Author(s):  
Rui Pang ◽  
Yibo Zhang ◽  
Longji Dang ◽  
Lanbo Zhang ◽  
Shuting Liang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cover Plate ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Concrete Floor ◽  
New Type ◽  
Vertical Bearing ◽  
Floor System ◽  
Bearing Behavior

This article proposes a new type of discrete connected precast reinforced concrete diaphragm floor system that consists of precast flat slabs and slab joint connectors. An experimental investigation of discrete connected new-type precast reinforced concrete diaphragm under a vertical distributed static load was conducted, and the effect of slab joint connectors on the load-bearing capacity was evaluated. Then, a finite element analysis of discrete connected new-type precast reinforced concrete diaphragm, precast reinforced concrete floors without slab connectors, and cast-in-situ reinforced concrete floor were performed to understand their working mechanism and determine the differences in load-bearing behavior. The results indicate that the load-bearing capacity and stiffness of discrete connected new-type precast reinforced concrete diaphragm increase considerably as the hairpin and cover plate hybrid slab joint connectors can efficiently connect adjacent precast slabs and enable them to work together under a vertical load by transmitting the shear and moment forces in the orthogonal slab laying direction. The deflection of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction is mainly caused by the opening deformation of the slab joint and the rotational deformation of the precast slabs. This flexural deformation feature can provide reference for establishing the bending stiffness analytical model of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction, which is vitally important for foundation of the vertical bearing capacity and deformation calculation method. The deflection and crack distribution patterns infer that the discrete connected new-type precast reinforced concrete diaphragm processes the deformation characteristic of two-way slab floor, which can provide a basis for the theoretical analysis of discrete connected new-type precast reinforced concrete diaphragm.

scholarly journals Experimental and Theoretical Study on the Cooling Performance of a CO2 Mobile Air Conditioning System

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1927 ◽  
Author(s):  
Dandong Wang ◽  
Binbin Yu ◽  
Junye Shi ◽  
Jiangping Chen
Keyword(s):  
Air Conditioning ◽  
Theoretical Study ◽  
Cooling Capacity ◽  
Air Conditioning System ◽  
Cooling Performance ◽  
System A ◽  
Hfc 134A ◽  
Expansion Valve ◽  
The Impact ◽  
Compressor Efficiency

CO2 (GWP = 1) is considered as a promising natural alternative refrigerant to HFC-134a in mobile air conditioning (MAC) applications. The objective of this study is to investigate the cooling performance characteristics of a CO2 MAC system. A prototype CO2 MAC system, consisting of a CO2 electrical compressor, CO2 parallel flow microchannel heat exchangers, and an electrical expansion valve, was developed and tested. Factor analysis experiments were conducted to reveal the effect of outdoor temperature on the cooling performance of this CO2 MAC system. Compared with a conventional R134a MAC system, the prototype CO2 MAC system achieved comparable cooling capacity, but had COP reductions of 26% and 10% at 27 °C and 45 °C outdoor conditions, respectively. In addition, based on refrigerant properties, theoretical cycle analysis was done to reveal the impact of evaporator, gas cooler and compressor, on the system cooling performance. It is concluded that the increase of overall compressor efficiency or the decrease of gas cooler approaching temperature could greatly improve the COP of this CO2 MAC system.

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