scholarly journals Heat transfer enhancement of the open-type heat recovery unit

2020 ◽  
Vol 177 ◽  
pp. 03019
Author(s):  
Stanislav Davydov ◽  
Rafail Apakashev ◽  
Konstantin Kokarev
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Combustion Products ◽  
Specific Humidity ◽  
Gas Temperature ◽  
Transfer Enhancement ◽  
Gas Combustion ◽  
Open Type ◽  
Heat Transfer Efficiency ◽  
Recovery Unit

An increase in the heat transfer efficiency of the open-type heat recovery unit due to the sequential heat and mass transfer enhancement is considered. The graphs of variances in the water temperature, gas temperature, gas enthalpy and gas specific humidity at the end of each site are presented. The proposed designs of the open-type heat recovery unit can be used for the flue gas disposal, including the disposal of natural gas combustion products in the greenhouse facility.

scholarly journals Heat Transfer Enhancement for site level indirect heat recovery systems using nanofluids as the intermediate fluid

2016 ◽  
Vol 105 ◽  
pp. 923-930 ◽  
Author(s):  
Amir H. Tarighaleslami ◽  
Timothy G. Walmsley ◽  
Martin J. Atkins ◽  
Michael R.W. Walmsley ◽  
James R. Neale
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Recovery ◽  
Transfer Enhancement

scholarly journals An experimental heat-transfer study for a heat-recovery unit made of corrugated tubes

2013 ◽  
Vol 53 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Primož Poredoš ◽  
Tomaž Šuklje ◽  
Sašo Medved ◽  
Ciril Arkar
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Experimental Heat ◽  
Recovery Unit ◽  
Experimental Heat Transfer ◽  
Transfer Study

scholarly journals A review on the thermal performance of nanofluid inside circular tube with twisted tape inserts

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402092489
Author(s):  
Saadah Ahmad ◽  
Shahrir Abdullah ◽  
Kamaruzzaman Sopian
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Volume Fraction ◽  
Fluid Mixing ◽  
Transfer Efficiency ◽  
Working Fluid ◽  
Twisted Tape ◽  
Transfer Enhancement ◽  
Heat Transfer Efficiency ◽  
Improve Heat Transfer

Working fluid with higher thermal conductivity and tube with better fluid mixing are two crucial elements for heat transfer enhancement in heat exchanger system. Hence, several methods and techniques have been explored to improve heat transfer efficiency, including dispersing nanoparticles into conventional heat transfer fluid and inserting instruments inside the tube of the heat exchanger. Studies have shown that nanofluid can improve heat transfer efficiency of the system due to its higher thermal conductivity and drastic Brownian motion of nanoparticles while inserts within tube can improve heat transfer efficiency by increasing axial velocity of working fluid for better fluid mixing. This article summarized 109 of journals from recent research on heat transfer enhancement of nanofluid flowing inside the tube with inserts as well as discussing the significant parameters that affected the system’s efficiency such as nanoparticles’ volume fraction, Reynolds number and types and configurations of inserts. Ultimately, analysis will be carried out to determine the most suitable modification of twisted tape inserts with the most optimum value of nanoparticle volume fraction for turbulence flow regime. Finally, some problems that need to be solved for future research such as agglomeration and pressure drop are discussed.

Heat Transfer Properties and Energy-Exergy Efficiency in a Finned Cross-Flow Heat Recovery Unit

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Isak Kotcioglu ◽  
Ahmet Cansiz
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Cross Flow ◽  
Exergy Loss ◽  
Entropy Generation Number ◽  
Recovery Unit ◽  
Transfer Unit ◽  
Flow Heat ◽  
Inlet Conditions ◽  
Transfer Properties

In this study, a cross-flow heat recovery-exchanger system operating with unmixed fluids was manufactured and tested. The thermodynamic analysis of the system was presented via determining the variations of exergy loss with Reynolds number. The analysis also included the effects of convergent and divergent plate-type winglets on heat transfer properties of the designed system. Experimental tests consisted of temperature and pressure drop measurements for the Reynolds numbers (3000 and 12,000) according to the working conditions of the boiler, fan, preheater, and reheater. The effects of inlet conditions of the working fluids on the heat transfer characteristics were correlated via entropy generation number and exergy loss. The variation of the effectiveness with the number of transfer unit of heat recovery unit was calculated and discussed in terms of literature.

Heat transfer analysis on dimple geometries and arrangements in dimple jacketed heat exchanger

2019 ◽  
Vol 29 (8) ◽  
pp. 2775-2791 ◽  
Author(s):  
Jin-yuan Qian ◽  
Zan Wu ◽  
Qian-Kun Zhang ◽  
Zhi-Jiang Jin ◽  
Bengt Ake Sunden
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Transfer Performance ◽  
Heat Transfer Analysis ◽  
Transfer Enhancement ◽  
Flow Temperature ◽  
Content Type ◽  
Heat Transfer Efficiency ◽  
Integrated Devices

Purpose The purpose of this paper is to study the effects of dimple geometries and arrangements on the heat transfer enhancement in a dimple jacketed heat exchanger. Design/methodology/approach For the purpose of this paper, with the experimental validated numerical model, this paper carries out numerical simulations of both single dimples with different geometries and the whole dimple jacketed heat exchanger with different dimple arrangements. For a single dimple, its secondary vortex flow, temperature differences and the pressure drop performance for different geometries are analyzed. For the whole dimple jacketed heat exchanger, the heat transfer and pressure drop performances are investigated by comparing the no dimple, triangular and rectangular dimple arrangements. Findings Results show that dimples can improve the heat transfer efficiency compared with conventional jacketed heat exchanger, and specific geometries and arrangement of dimples for better heat transfer performance are figured out. Originality/value This paper considers both dimple geometries and arrangements, which can be useful for further applications in specific integrated devices or similar applications.

Numerical Simulation of the Influence of Deposits on Heat Transfer Process in a Heat Recovery Steam Generator

2011 ◽  
Vol 121-126 ◽  
pp. 1301-1305
Author(s):  
Lin Mu ◽  
Hong Chao Yin
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Flue Gas ◽  
Transfer Rate ◽  
Heat Recovery ◽  
Heat Transfer Process ◽  
Heat Recovery Steam Generator ◽  
Tube Surface ◽  
Total Heat Transfer ◽  
Heat Transfer Efficiency

Flue gas entrains a large number of ash particles which are composed of alkali substances into the heat recovery steam generator (HRSG). The deposition of particles on the tube surface of heat transfer can reduce the heat transfer efficiency significantly. In the present work, an Eulerian- Lagrangian model based on Computational Fluid Dynamics (CFD) is implemented to simulation flue gas turbulent flow, heat transfer and the particle transport in the HRSG. Several User-Defined Functions (UDFs) are developed to predict the particle deposition/ rebounding as well as the influence of physical properties and microstructure of deposits on the heat transfer process. The results show that only after one day deposition, the total heat transfer rate reduces 27.68% compared with the case no deposition. Furthermore, the total heat transfer rate reduces to only 238.74kW after 30 days of continuous operation without any slag removal manipulation. Both numerical simulation and field measurement identify that the deposits play an important role in the heat transfer in the HRSG. Especially, when the deposits can’t be removed designedly according to the actual operating conditions, the HRSG experiences a noticeable decline in heat transfer efficiency due to continuous fouling and slagging on the tube surface.

scholarly journals Adaptation of a Mathematical Model of Generalized Heat Exchange in Furnaces

2020 ◽  
Vol 20 (4) ◽  
pp. 12-22
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Gas Flow ◽  
Calculated Data ◽  
Combustion Products ◽  
Steam Boiler ◽  
Gas Temperature ◽  
Condi Tions ◽  
Proposed Model ◽  
The Mathematical Model

Consideration of the scheme of flows of combustion products in furnaces and flow chambers of combus-tion within the framework of the heat transfer paradigm made it possible to determine the ratio of the genera-lized mechanisms of heat transfer – convection and radiation. The transition from uniform distribution of gas flow velocity to uneven distribution in furnaces with a geometrically peculiar fence has been implemented. This made it possible to take into account the use of recirculation gases, dual-light shades, changes in the shape and size of the cross-section of the furnace, and installation of shade surfaces in a furnace. The condi-tions for the correctness of the mathematical model are considered, and the eigenvalues of the boundary value problem under conditions of an asymmetric temperature field and the function of the gas temperature changing along the height of the furnace are obtained. A comparative analysis of the nature of the change in gas temperature with height according to the proposed model with the calculation for a steam boiler with a capacity of 950 t/h according to the standard method showed a satisfactory agreement of the calculated data with an accuracy of +4.87 %.

Sign in / Sign up

Export Citation Format

Share Document