scholarly journals Analysis of the Efficiency of Using Heat Exchangers with Porous Inserts in Heat and Gas Supply Systems

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5854 ◽  
Author(s):  
Natalia Rydalina ◽  
Elena Antonova ◽  
Irina Akhmetova ◽  
Svetlana Ilyashenko ◽  
Olga Afanaseva ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Heat Exchangers ◽  
Theoretical Calculations ◽  
Residential Buildings ◽  
Classical Equation ◽  
Porous Metal ◽  
Compact Heat Exchangers ◽  
Equation Boundary ◽  
Particular Solution ◽  
Gas Supply

The creation of efficient and compact heat exchangers is one of the priority tasks arising during the design of heat and gas supply to industrial and residential buildings. As a rule, finned surfaces and turbulization of heat carrier flows are used to increase the efficiency of heat exchange in heat exchangers. The present paper proposes to use novel materials, namely porous material, in the design of highly efficient heat exchangers. The investigation was carried out experimentally and theoretically. To study the possibility of creating such heat exchangers, a multi-purpose test bench is created. The aim of the study was to assess the intensity of heat transfer in heat exchangers using porous metal. Laboratory tests are carried out as part of the experimental study. In the theoretical study, the classical equation for the change in the heat flux density when the coolant passes through the porous insert was used. As a result, a mathematical model was obtained in the form of a second-order differential equation. Boundary conditions were set and a particular solution was obtained. The results of theoretical calculations were compared with experimental data. The performed study experimentally confirmed the efficiency of using porous metal inserts in the design of shell-and-tube heat exchangers. The compiled mathematical model allows one to perform engineering calculations of the considered heat exchangers with porous inserts.

scholarly journals Hydraulic Calculation of Copper Pipelines for Heating and Internal Gas Supply Systems

2018 ◽  
Vol 17 (6) ◽  
pp. 508-514
Author(s):  
M. A. Rutkowski ◽  
A. S. Shybeka ◽  
K. I. Halynia
Keyword(s):  
Pressure Loss ◽  
Theoretical Calculations ◽  
Residential Buildings ◽  
Hydraulic Calculation ◽  
Design Standards ◽  
Heating Systems ◽  
Local Loss ◽  
Supply Systems ◽  
Gas Supply

Copper pipelines are widely used while designing modern heating systems, water and gas supply of residential buildings and these pipelines have a number of advantages in comparison with steel and plastic pipelines. The main reason for limited use of copper pipes is their cost which is practically twice as much as cost of steel pipes, and four times higher than the coat of polypropylene pipes. Modern design standards in Belarus do not contain specific requirements for calculation of copper pipelines. Therefore hydraulic calculation of heating systems has been considered and analyzed on the basis of norms of Russian Federation. The drawback of all theoretical calculations presented in Russian standards is their abstraction from general laws of fluid and gas mechanics. For this reason theoretical foundations of hydraulic calculations for all pipelines have been considered and expressions have been given for determination of pressure loss due to friction and in local loss. Main flow regimes have been considered on the basis of I. Nikuradze’s experiments in order to determine linear losses and dependences for determination of friction coefficient in laminar, transient and turbulent modes have been presented in the paper. Values of local loss coefficient for main pipeline elements are given for calculation of pressure loss and the paper also shows determination of value z with due account of equipment capacity. An analysis of nomograms presented in Russian norms and researches has been carried out; shortcomings have been revealed and the ways directed on their perfection have been found. Nomograms for calculation of specific pressure losses in heating systems and internal gas supply have been constructed on the basis of natural gas and propane with due account of dependences presented in the paper. Nomograms for finding equivalent length of a single local loss have been constructed for calculation of internal gas supply systems.

Experimental investigation and mathematical model of a heat exchanger with porous metal inserts

2020 ◽  
Vol 6 (2) ◽  
pp. 22-40
Author(s):  
Boris G. Aksenov ◽  
Oleg A. Stepanov ◽  
Natalia V. Rydalina
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Theoretical Data ◽  
Porous Metal ◽  
Porous Metals ◽  
Standard Methods ◽  
Porous Aluminum ◽  
The Status

When creating and manufacturing heat exchangers, one of the main tasks is to increase the efficiency of heat transfer. The use of porous metals in heat exchangers is one of the promising ways to increase the heat transfer intensity, which determines the relevance of the study. The paper provides an overview of the status of this issue on literary sources. The purpose of the work is to conduct an experimental study of a heat exchanger with porous materials, to compile a mathematical model that allows analytical calculations of such heat exchangers, to confirm the correctness of the compiled model experimentally. An experimental bench has been created to study a heat exchanger that uses porous aluminum. The hot fluid is warm water that flows through pipes passing through a porous metal. The cold coolant flowing through the pores is freon, which cools the water. A schematic diagram and description of the stand are presented. A test cycle has been conducted. A comparison of the heat transfer intensity for materials of different porosity is given. Using standard methods for calculating heat exchangers in this case is not possible due to the lack of standard methods for determining the area of the inner surface with pores. In the course of the work, the standard equation describing the cooling of a porous body was proposed to be supplemented by the function of distributed heat sources. As a result, we have obtained a mathematical model of the heat exchanger under consideration in a simplified form, which can be used in technical calculations. The calculation results by the obtained method are correlated with the data of experiments. Deviations of empirical and theoretical data are within acceptable limits. The results obtained make it possible to use porous metals in order to increase the heat transfer intensity in the manufacture of heat exchangers. This technique allows calculations with an unknown heat exchange surface area, taking into account the heat capacity and heat of phase transition, if any. According to the methodology, the article is experimental-theoretical. Experiments are being conducted on the created laboratory bench. In parallel, calculations are made according to the developed mathematical model. The results are compared. Conclusions are made of a theoretical and applied nature.

A Comparison of Tapered and Straight Circular Pin-Fin Compact Heat Exchangers for Electronic Appliances

2009 ◽  
Vol 16 (3) ◽  
pp. 301-314
Author(s):  
A. Dewan ◽  
V. Bharti ◽  
V. Mathur ◽  
U. K. Saha ◽  
P. Patro
Keyword(s):  
Heat Exchangers ◽  
Compact Heat Exchangers ◽  
Pin Fin

Research of pressure influence in the gas supply system on the energy consuption level of gas devices

2019 ◽  
Vol 6 (2) ◽  
pp. 56-63
Author(s):  
L. D. Pylypiv ◽  
І. І. Maslanych
Keyword(s):  
Natural Gas ◽  
Residential Buildings ◽  
Supply System ◽  
Normal Operation ◽  
Gas Combustion ◽  
Efficient Operation ◽  
Gas Consumption ◽  
Natural Gas Combustion ◽  
Gas Supply

There are investigated the influence of operating pressures in the gas supply system on the level of such energy indicators as efficiency, gas flow and gas overrun by gas equipment in residential buildings. There is established a relationship between the values of operating pressures in the gas supply system and the gas consumption level of household appliances. The causes of insufficient pressure in the gas networks of settlements are analyzed in the article. There is also developed an algorithm for calculating the change in the efficiency of gas appliances depending on the operational parameters of the gas network. It has been found that the most efficient operation of gas appliances is observed at an overpressure at the inlet of gas appliances of about 1200 Pa.To ensure the required quality of natural gas combustion among consumers and minimize gas consumption there are justified the following measures in the article: coordinating a domestic regulatory framework for assessing the quality of natural gas with international norms and standards; improving the preparation of gas coming from local wells before supplying it to gas distribution networks; auditing low pressure gas pipelines and reconstructing areas affected by corrosion; ensuring standard gas pressure in the network for the normal operation of domestic gas appliances; stating quality indicators of natural gas combustion by gas sales organizations.

modeFRONTIER for Virtual Design and Optimization of Compact Heat Exchangers

2014 ◽  
Author(s):  
Marco Carriglio ◽  
Alberto Clarich ◽  
Rosario Russo ◽  
Enrico Nobile ◽  
Paola Ranut
Keyword(s):  
Heat Exchangers ◽  
Virtual Design ◽  
Design And Optimization ◽  
Compact Heat Exchangers
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