scholarly journals ANALISIS EFISIENSI BOILER DENGAN METODE INPUT– OUTPUT DI PT. JAPFA COMFEED INDONESIA Tbk. UNIT BANJARMASIN

2019 ◽  
Vol 4 (1) ◽  
pp. 37-46
Author(s):  
Imam Muzaki ◽  
Aqli Mursadin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Process ◽  
Transfer Rate ◽  
Heat Transfer Process ◽  
Heat Losses ◽  
Input Output ◽  
Research Results ◽  
Boiler Efficiency

This paper shows some of the research results. The result of this research shows that the boiler efficiency at operational condition (present) is 79,32% decreased efficiency equal to 9,19% compared with operational condition with efficiency as big as 88,51%. One of the factors analyzing the declining efficiency of the boiler is greatly influencing the heat transfer process, because if there is dirt or crust on the boiler pipe and the fouling, it will result in the process of heat transfer will decrease so that the heat transfer rate will decrease, and will also affect the amount of heat losses in the boiler.

Numerical Simulation of Natural Convection in a Two-Dimensional Enclosure Filled with Nanofluids

2012 ◽  
Vol 560-561 ◽  
pp. 1184-1187
Author(s):  
Su Fen Zhao ◽  
Xin Fang Li
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Transfer Rate ◽  
Transfer Process ◽  
Transfer Rate ◽  
Mass Fraction ◽  
Heat Transfer Process ◽  
Two Dimensional ◽  
Grashof Number ◽  
Transfer Properties

The natural convection of nanofluids in a two-dimensional enclosure is numerically simulated with Fluent software. The effect of copper particle concentration and Grashof number on heat transfer properties is investigated. The results indicate that the suspended copper nanoparticles substantially increase the heat transfer rate at any given Grashof number, and the heat transfer rate of the nanofluid increases remarkably with the mass fraction of nanoparticles. For a given initial Grashof number, as the mass fraction increases, the velocity components of nanofluid increase as a result of an increase in the energy transport through the fluid. In addition, the intensity of the streamline increase with the increases of the Grashof number, which indicate the heat transfer properties are enhanced. The heat transfer process is dominant with the heat exchange at low Gr, while the heat transfer process is dominant with the natural convection at high Gr.

scholarly journals Analytical solution and process analysis of energy pile’s heat transfer rate

2020 ◽  
Vol 205 ◽  
pp. 05026
Author(s):  
Jun Yang ◽  
Zhenguo Yan ◽  
Zhengwei Zhang ◽  
Shu Zeng
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Heat Transfer Performance ◽  
Heat Transfer Process ◽  
Transfer Performance ◽  
Energy Pile ◽  
Energy Piles ◽  
The Difference ◽  
Surrounding Soil

With the ever-increasing energy demand and implications of climate change, the use of energy piles to absorb shallow geothermal energy to regulate room temperature of buildings is considered the best sustainable energy technology, especially in China, and the use of this technology is becoming increasingly popular. At present, studies generally uses the temperature field to analyze the heat transfer performance of the energy pile, which cannot represent the heat transfer rate distribution intuitively. In this study, we used mathematical models to provide an analytical solution to determine the heat transfer rate distribution between the energy pile and surrounding soil. Analysis of the heat transfer process of concrete piles in clay showed that the difference in thermal properties between the energy pile and the surrounding soil affected the whole heat transfer process, especially in the initial stage. The time required to reach the quasi-steady state mainly depended on the pile’s volume heat capacity, the thermal diffusivity of the pile and the surrounding soil. In engineering practice, to enhance the heat transfer performance of energy piles, the following measures can be taken: reduce the difference in thermal properties between the energy pile and surrounding soil and increase the distance between energy piles to improve the heat transfer conditions.

Heat Transfer Augmentation in Solar Collectors Using Nanofluids: A Review

2020 ◽  
Vol 6 (2) ◽  
pp. 72-81 ◽  
Author(s):  
Morteza Anbarsooz ◽  
Maryam Amiri ◽  
Iman Rashidi ◽  
Mohammad Javadi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Heat Transfer Process ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Optical Parameters ◽  
Solar Collectors ◽  
Direct Absorption ◽  
Heat Transfer Augmentation

Background: Enhancing the heat transfer rate in solar collectors is an essential factor for reducing the size of the system. Yet, various methods have been presented in the literature to increase the heat transfer rate from an absorber to the heat transfer fluid. The most important methods are: the use of evacuated receivers, addition of swirl generators/turbulators and use of various nanofluids as the heat transfer fluid. Objective: The current study reviews the achievements in the enhancement of solar collectors’ heat transfer process using various types of nanofluids. The review revealed that the most widely employed nanoparticles are Al2O3 and Carbon nanotubes (CNTs) and the most popular base fluid is water. Most of the investigations are performed on indirect solar collectors, while recently, the researchers focused on direct absorption methods. In the indirect absorption collectors, the thermal conductivity of the working fluid is essential, while in a direct absorption collector, the optical properties are also crucial. Optimization of the optical parameters along with the thermophysical properties of the nanofluid is suggested for the applications of solar collector.

Overall Efficiency of a Radial Fin Assembly Under Dehumidifying Conditions

1998 ◽  
Vol 120 (4) ◽  
pp. 299-304 ◽  
Author(s):  
L. Rosario ◽  
M. M. Rahman
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Exchanger ◽  
Relative Humidity ◽  
Heat And Mass Transfer ◽  
Heat Transfer Rate ◽  
Transfer Process ◽  
Transfer Rate ◽  
Total Heat ◽  
Overall Efficiency

The aim of this paper is the analysis of heat transfer in a radial fin assembly during the process of dehumidification. An individual finned tube geometry is a reasonable representation of heat exchangers used in air conditioning. The condensation process involves both heat and mass transfer and the cooling takes place by the removal of sensible as well as latent heat. The ratio of sensible to total heat is an important quantity that defines the heat transfer process during a dehumidifier operation. A one-dimensional model for heat transfer in the fin and the heat exchanger block is developed to study the effects of condensation on the fin surface. The combined heat and mass transfer process is modeled by incorporating the ratio of sensible to total heat in the formulation. The augmentation of heat transfer due to fin was established by comparing the heat transfer rate with and without fins under the same operating conditions. Calculations were carried out to study the effects of relative humidity and dry bulb temperature of the incoming air, and cold fluid temperature inside the coil on the performance of the heat exchanger. An analysis of the overall efficiency for the assembly was also done. Results were compared to those under dry conditions, wherever appropriate. Comparison between present results and those published for rectangular as well as radial fins under fully wet conditions were made. These comparisons established the validity of the present model. It was found that the heat transfer rate increased with increment in both dry bulb temperature and relative humidity of the air. The augmentation factor, however, decreased with increment in relative humidity and the dry bulb temperature. The fin efficiency decreased with relative humidity.

Analysis of Effect of Fouling on Thermodynamic Performance of Convective Heat Transfer Process Through a Duct

2002 ◽  
Author(s):  
Shuangying Wu ◽  
Danling Zeng
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Convective Heat Transfer ◽  
Transfer Process ◽  
Wall Temperature ◽  
Transfer Rate ◽  
Heat Transfer Process ◽  
Constant Wall Temperature ◽  
Thermodynamic Performance ◽  
Increase Rate

Based on the first and second laws of thermodynamics simultaneously, the effect of fouling on the thermodynamic performance of convective heat transfer process through a duct with constant wall temperature and constant heat flux is investigated analytically when the flow is turbulent. A criterion evaluating the effect of fouling is defined as the entropy generation increase rate per unit heat transfer rate. The effect of Reynolds number (not considering fouling) and dimensionless inlet temperature difference and dimensionless wall heat flux on the entropy generation increase rate per unit heat transfer rate is discussed. In addition, the results with constant wall temperature are compared with that with constant wall heat flux.

Design of the Blast Furnace Wall Structure Made of Efficient Materials. Part 4. Calculation Examples

2020 ◽  
Vol 786 (11) ◽  
pp. 30-34
Author(s):  
A.M. IBRAGIMOV ◽  
◽  
L.Yu. GNEDINA ◽  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Blast Furnace ◽  
Boundary Value Problems ◽  
Transfer Process ◽  
Rational Design ◽  
Boundary Value ◽  
Heat Transfer Process ◽  
Furnace Wall ◽  
Time Interval

This work is part of a series of articles under the general title The structural design of the blast furnace wall from efficient materials [1–3]. In part 1, Problem statement and calculation prerequisites, typical multilayer enclosing structures of a blast furnace are considered. The layers that make up these structures are described. The main attention is paid to the lining layer. The process of iron smelting and temperature conditions in the characteristic layers of the internal environment of the furnace is briefly described. Based on the theory of A.V. Lykov, the initial equations describing the interrelated transfer of heat and mass in a solid are analyzed in relation to the task – an adequate description of the processes for the purpose of further rational design of the multilayer enclosing structure of the blast furnace. A priori the enclosing structure is considered from a mathematical point of view as the unlimited plate. In part 2, Solving boundary value problems of heat transfer, boundary value problems of heat transfer in individual layers of a structure with different boundary conditions are considered, their solutions, which are basic when developing a mathematical model of a non-stationary heat transfer process in a multi-layer enclosing structure, are given. Part 3 presents a mathematical model of the heat transfer process in the enclosing structure and an algorithm for its implementation. The proposed mathematical model makes it possible to solve a large number of problems. Part 4 presents a number of examples of calculating the heat transfer process in a multilayer blast furnace enclosing structure. The results obtained correlate with the results obtained by other authors, this makes it possible to conclude that the new mathematical model is suitable for solving the problem of rational design of the enclosing structure, as well as to simulate situations that occur at any time interval of operation of the blast furnace enclosure.

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