scholarly journals INCREASE THE EFFICIENCY OF GRAIN COOLING AFTER DRYING AND HEAT TREATMENT

2021 ◽  
pp. 111-120
Author(s):  
Borys Kotov ◽  
Roman Kalinichenko ◽  
Anatoliy Rud Anatoliy Rud ◽  
Sergiy Hrushetskiy
Keyword(s):  
Heat Transfer ◽  
Air Flow ◽  
Ambient Air ◽  
Pneumatic Transport ◽  
High Quality ◽  
Bucket Elevator ◽  
Cooling Air ◽  
Independent Mode ◽  
Cooling Part

One of the main requirements for grain dryers is the need for high-quality cooling of grain material after drying. Today, the most widespread are grain coolers built into grain dryers. As the practice of operation has shown, the most widespread in agriculture mine grain dryers with their cooling zones are ineffective: the temperature of the grain after cooling often exceeds the ambient air temperature by 15-30 0C, which is unacceptable. Devices with boxes have such disadvantages as uneven distribution air in the volume of grain mass and the corresponding uneven temperature field of the cooling air, limited opportunities for intensifying heat transfer during grain cooling. More promising for agricultural grain dryers are external coolers, which are installed separately from the dryer and can operate in an independent mode, which has a number of advantages: the quality of cooling improves, the productivity of existing grain dryers increases due to the use of the cooling part as a dryer. The main disadvantages of using the existing external column coolers: the need for an additional vehicle - a bucket elevator for reloading grain from the dryer to the column; vertical arrangement, it is necessary to use transporting means for grain for feeding to a considerable height. But if a pneumatic transport loader with a pulsating air flow is used as a vehicle, then the efficiency of the coolers can be increased due to the removal of a part of the heat accumulated by the grain by the transporting air flow. The paper proposes an analytical rationale for increasing the efficiency of coolers with pneumatic transport in a pulsating air flow.

Transient Heat Transfer Simulation in Rapid Heat Cycle Molding with Electric Heating

2012 ◽  
Vol 497 ◽  
pp. 121-125
Author(s):  
Shao Fei Jiang ◽  
Yin Kong ◽  
Ji Quan Li ◽  
Guo Zhong Chai
Keyword(s):  
Heat Transfer ◽  
Injection Molding ◽  
Temperature Response ◽  
Electric Heating ◽  
High Quality ◽  
Heat Cycle ◽  
Heat Transfer Simulation ◽  
Plastic Injection ◽  
Plastic Products

The demand of high quality for plastic products has facilitated the development of Plastic Injection Molding Technology, many new sorts of methods were created to improve the surface quality of plastic products, such as Rapid Heat Cycle Molding. But the temperature response law hasn’t figured out yet, and the influence elements of this process haven’t been clear, which seriously delay the appliction of Rapid Heat Cycle Molding.

Highest-Efficient Film Cooling by Improved NEKOMIMI Film Cooling Holes: Part 1 — Ambient Air Flow Conditions

2013 ◽  
Author(s):  
Karsten Kusterer ◽  
Nurettin Tekin ◽  
Frederieke Reiners ◽  
Dieter Bohn ◽  
Takao Sugimoto ◽  
...  
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Air Flow ◽  
Ambient Air ◽  
Flow Conditions ◽  
Test Rig ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Cooling Technology ◽  
Cooling Air

In modern gas turbines, the film cooling technology is essential for the protection of the hot parts, in particular of the first stage vanes and blades of the turbine, against the hot gases from the combustion process in order to reach an acceptable life span of the components. As the cooling air is usually extracted from the compressor, the reduction of the cooling effort would directly result to an increased thermal efficiency of the gas turbine. Understanding of the fundamental physics of film cooling is necessary for the improvement of the state-of-the-art. Thus, huge research efforts by industry as well as research organizations have been undertaken to establish high efficient film cooling technologies. It is a today common knowledge that film cooling effectiveness degradation is caused by secondary flows inside the cooling jets, i.e. the Counter-Rotating Vortices (CRV) or sometimes also mentioned as kidney-vortices, which induce a lift-off of the jet. Further understanding of the secondary flow development inside the jet and how this could be influenced, has led to hole configurations, which can induce Anti-Counter-Rotating Vortices (ACRV) in the cooling jets. As a result, the cooling air remains close to the wall and is additionally distributed flatly along the surface. Beside different other technologies, the NEKOMIMI cooling technology is a promising approach to establish the desired ACRV. It consists of a combination of two holes in just one configuration so that the air is distributed mainly on two cooling air streaks following the special shape of the generated geometry. The original configuration was found to be difficult for manufacturing even by advanced manufacturing processes. Thus, the improvement of this configuration has been reached by a set of geometry parameters, which lead to configurations much easier to be manufactured but preserving the principle of the NEKOMIMI technology. Within a numerical parametric study several advanced configurations have been obtained and investigated under ambient air flow conditions similar to conditions for a wind tunnel test rig. By systematic variation of the parameters a further optimization with respect to highest film cooling effectiveness has been performed. A set of most promising configurations has been also investigated experimentally in the test rig. The best configuration outperforms the basic configuration by 17% regarding the overall averaged adiabatic film cooling effectiveness under the experimental conditions.

Numercial Simulation of Sinter Cooling Process

2010 ◽  
Author(s):  
Fengguo Tian ◽  
D. Frank Huang ◽  
Chenn Q. Zhou
Keyword(s):  
Heat Transfer ◽  
Initial Temperature ◽  
Air Flow ◽  
Convection Heat Transfer ◽  
Cooling Process ◽  
Initial Temperature Distribution ◽  
Cooling Air Flow ◽  
Sinter Cooler ◽  
Cooling Air ◽  
Cooling Model

A 2-D sinter cooling model is built to simulate the hot iron ore sinter cooling process in a sinter cooler. In this model the convection heat transfer is applied for the heat transfer between the sinter particle skin and the cooling air flow. Thermal conduction is used for the heat conduction within the sinter particles, and fluid dynamics is applied tothe cooling gas distributions. This model will be able to analyze the effects of sinter particle size, size distribution, hot sinter initial temperature, initial temperature distribution, sinter cooler size, cooler configuration and cooling air flow rate as well as cooling air temperature on the sinter cooling process. In this paper the 2-D sinter cooling model is presented along with certain parametric study examples.

Heat Exchange Effectiveness and Pressure Drop for Air Flow Through Perforated Plates With and Without Crosswind

1994 ◽  
Vol 116 (2) ◽  
pp. 391-399 ◽  
Author(s):  
C. F. Kutscher
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Pressure Drop ◽  
Air Flow ◽  
Ambient Air ◽  
Perforated Plates ◽  
Wind Speeds ◽  
New Type ◽  
Flow Through ◽  
Heat Exchange Effectiveness

Low-porosity perforated plates are being used as absorbers for heating ambient air in a new type of unglazed solar collector. This paper investigates the convective heat transfer effectiveness for low-speed air flow through thin, isothermal perforated plates with and without a crosswind on the upstream face. The objective of this work is to provide information that will allow designers to optimize hole size and spacing. In order to obtain performance data, a wind tunnel and small lamp array were designed and built. Experimental data were taken for a range of plate porosities from 0.1 to 5 percent, hole Reynolds numbers from 100 to 2000, and wind speeds from 0 to 4 m/s. Correlations were developed for heat exchange effectiveness and also for pressure drop. Infrared thermography was used to visualize the heat transfer taking place at the surface.

Enhancement of Tire Durability by Considering Air Flow Field5

2009 ◽  
Vol 37 (2) ◽  
pp. 103-121 ◽  
Author(s):  
K. Kato ◽  
M. Yamaguchi ◽  
T. Miyazono ◽  
M. Tsuruta
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
High Temperature ◽  
Air Flow ◽  
Ambient Air ◽  
General Phenomenon ◽  
Elasticity Parameter ◽  
Experimental Works ◽  
Flow Turbulence

Abstract Rolling tire performance is frequently affected by multiple physics. For instance, dry handling is influenced by the tire temperature as a consequence of the heat generation by material viscosity and the heat transfer to ambient air. The general phenomenon is complex and even interactive in that the elasticity parameter affecting tire deformation is a function of the temperature and that the temperature depends considerably on the air flow on tire surface. This paper refers to connecting the different physics of outside air flow and thermomechanical system of tire. Especially, the heat transfer across tire surface is focused from the viewpoint of thermofluid dynamics. Macroscopic flow turbulence to accelerate the heat transfer is studied in a case study of the run-flat tire, where high temperature due to very large deformation is of a key issue. Numerical simulation is conducted in parallel to experimental works in assessing heat flow and temperature on the surface. It is shown that the proposed geometry of rib sidewall reduces the tire temperature and improves the tire life remarkably.

Application of Conjugate CFD to the Internal Cooling Air Flow System of Gas Turbines

2003 ◽  
Author(s):  
D. Brillert ◽  
H. J. Dohmen ◽  
F.-K. Benra ◽  
O. Schneider ◽  
A. V. Mirzamoghadam
Keyword(s):  
Heat Transfer ◽  
Thermal Effects ◽  
Gas Turbines ◽  
Air Flow ◽  
Jet Flow ◽  
Calculation Procedure ◽  
Internal Cooling ◽  
Cooling Air Flow ◽  
Cooling Air ◽  
Material Temperature

Continuous improvements of the secondary air system are basic elements to increase efficiency and power of heavy duty gas turbines. It is becoming more important to perform a precise calculation of the heat transfer characteristics and to produce accurate predictions of the air/metal temperature in the internal cooling air system. Thermal effects influences the cooling behavior and consequently the cooling efficiency and the material temperature. The material temperature influences the stresses and the creep behavior that is important for life prediction and the reliability of the engine. Furthermore, the material temperature influences the clearances and therefore, the cooling mass-flow. This paper deals with a complex internal blade feed system comprising a forced radially-inward jet-flow into a large rotating cavity and the numerical coupling of different cooling air flow passages with component heat transfer, i.e. conjugate CFD. A calculation procedure was adopted to reproduce the measured rotating main shaft temperatures from the Siemens Model V84.3A gas turbine prototype. Based on this procedure, flow and heat transfer throughout the sub-cavities were discussed and the shaft temperature distribution was obtained. Results indicate a strong interaction between the thermal effects of the cooler radial jet-flow and the hotter seal gap regions. Moreover, the deficiencies in the adopted calculation procedure were identified.

Influence of technology parameters of free-cutting steel continuous casting on the billet internal structure

2020 ◽  
Vol 76 (2) ◽  
pp. 139-142
Author(s):  
A. T. Kunakbaeva ◽  
A. M. Stolyarov ◽  
M. V. Potapova
Keyword(s):  
Regression Analysis ◽  
Continuous Casting ◽  
Internal Structure ◽  
Sulfur Content ◽  
Manganese Content ◽  
High Quality ◽  
Correlation And Regression Analysis ◽  
Cutting Steel ◽  
Continuously Cast

Free-cutting steel gains specific working properties thanks to the high content of sulfur and phosphorus. These elements, especially sulfur, have a rather high tendency to segregation. Therefore, segregation defects in free-cutting steel continuously cast billets can be significantly developed. The aim of the work was to study the influence of the chemical composition of freecutting steel and casting technological parameters on the quality of the macrostructure of continuously cast billets. A metallographic assessment of the internal structure of cast metal made of free-cutting steel and data processing by application of correlation and regression analysis were the research methods. The array of production data of 43 heats of free-cutting steel of grade A12 was studied. Steel casting on a five-strand radial type continuous casting machine was carried out by various methods of metal pouring from tundish into the molds. Metal of 19 heats was poured with an open stream, and 24 heats – by a closed stream through submerged nozzles with a vertical hole. High-quality billets had a cross-sectional size of 150×150 mm. The macrostructure of high-quality square billets made of free-cutting steel of A12 grade is characterized by the presence of central porosity, axial segregation and peripheral point contamination, the degree of development of which was in the range from 1.5 to 2.0 points, segregation cracks and strips – about 1.0 points. In the course of casting with an open stream, almost all of these defects are more developed comparing with the casting by a closed stream. As a result of correlation and regression analysis, linear dependences of the development degree of segregation cracks and strips both axial and angular on the sulfur content in steel and on the ratio of manganese content to sulfur content were established. The degree of these defects development increases with growing of sulfur content in steel of A12 grade. These defects had especially strong development when sulfur content in steel was of more than 0.10%. To improve the quality of cast metal, it is necessary to have the ratio of the manganese content to the sulfur content in the metal more than eight.

Experience of clinical testing of personal telemedicine system ‘Obereg’ for remote monitoring of patients in intensive care units

2020 ◽  
pp. 52-58 ◽  
Author(s):  
A. A. Eryomenko ◽  
N. V. Rostunova ◽  
S. A. Budagyan ◽  
V. V. Stets
Keyword(s):  
Intensive Care ◽  
Intensive Care Units ◽  
Remote Monitoring ◽  
Clinical Testing ◽  
Transportation Of Patients ◽  
High Quality ◽  
Telemedicine System ◽  
Accuracy Of Measurements ◽  
Hospital Equipment

The experience of clinical testing of the personal telemedicine system ‘Obereg’ for remote monitoring of patients at the intensive care units of leading Russian clinics is described. The high quality of communication with the remote receiving devices of doctors, the accuracy of measurements, resistance to interference from various hospital equipment and the absence of its own impact on such equipment were confirmed. There are significant advantages compared to stationary patient monitors, in particular, for intra and out-of-hospital transportation of patients.

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