scholarly journals Thermal performance measurement of additive manufactured high-temperature compact heat exchangers

2021 ◽  
Vol 2116 (1) ◽  
pp. 012095
Author(s):  
M. Fuchs ◽  
D. Heinrich ◽  
X. Luo ◽  
S. Kabelac
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Fluid Temperature ◽  
Test Rig ◽  
Temperature Heat

Abstract Due to increased distribution of high-temperature processes in energy and process plants, more efficient and compact high-temperature heat exchangers are being developed. The additive manufacturing allows the construction of compact sizes and application-specific requirements. To evaluate the thermal performance of these heat exchangers, experimental investigations are evident. This study presents a test rig for testing compact high-temperature heat exchangers as well as a first set of thermal performance data of an additively manufactured plate-fin heat exchanger. The test rig can provide a maximum fluid temperature of 900°C and a maximum mass flow rate of 0.8 kg/min. A steam unit can add steam to the fluid stream to evaluate the influence of gas radiation on the thermal performance. The capabilities of this test rig are being tested with the plate-fin heat exchanger, varying the mass flow rate between 0.2 - 0.52 kg/min at a hot and cold inlet temperature of 750°C and 250°C. The overall effectiveness of the heat exchanger is approx. 0.9.

scholarly journals Analytical and Experimental Investigation of a Plate Fin Heat Exchanger at Cryogenics Temperature

2021 ◽  
Vol 39 (4) ◽  
pp. 1225-1235
Author(s):  
Ajay K. Gupta ◽  
Manoj Kumar ◽  
Ranjit K. Sahoo ◽  
Sunil K. Sarangi
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Cryogenic Temperature ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Compact Size

Plate-fin heat exchangers provide a broad range of applications in many cryogenic industries for liquefaction and separation of gasses because of their excellent technical advantages such as high effectiveness, compact size, etc. Correlations are available for the design of a plate-fin heat exchanger, but experimental investigations are few at cryogenic temperature. In the present study, a cryogenic heat exchanger test setup has been designed and fabricated to investigate the performance of plate-fin heat exchanger at cryogenic temperature. Major parameters (Colburn factor, Friction factor, etc.) that affect the performance of plate-fin heat exchangers are provided concisely. The effect of mass flow rate and inlet temperature on the effectiveness and pressure drop of the heat exchanger are investigated. It is observed that with an increase in mass flow rate effectiveness and pressure drop increases. The present setup emphasis the systematic procedure to perform the experiment based on cryogenic operating conditions and represent its uncertainties level.

Transient Response of a Cross Flow Heat Exchanger Subjected to Temperature and Flow Perturbations

2015 ◽  
Author(s):  
Karthik Silaipillayarputhur ◽  
Stephen A. Idem
Keyword(s):  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Transient Performance ◽  
Numerical Predictions ◽  
Minimum Capacity ◽  
Flow Heat

The transient performance of a multi-pass cross flow heat exchanger subjected to temperature and mass flow rate perturbations, where the heat exchanger flow circuiting is neither parallel flow nor counter flow, is considered in this work. A detailed numerical study was performed for representative single-pass, two-pass, and three-pass heat exchangers. Numerical predictions were obtained for cases where the minimum capacity rate fluid was subjected to a step change in inlet temperature in absence of mass flow rate perturbations. Likewise, numerical predictions were obtained for the heat exchangers operating initially at steady state, where a step mass flow rate change of the minimum capacity rate fluid was imposed in the absence of any fluid temperature perturbations. The transient performance of this particular heat exchanger configuration subjected to these temperature and flow disturbances has not been discussed previously in the available literature. In the present study the energy balance equations for the hot and cold fluids and the heat exchanger wall were solved using an implicit central finite difference method. A parametric study was conducted by varying the dimensionless quantities that govern the transient response of the heat exchanger over a typical range of values. Because of the storage of energy in the heat exchanger wall, and finite propagation times associated with the inlet perturbations, the outlet temperatures of both fluids do not respond instantaneously. The results are compared with previously published transient performance predictions of multi-pass counter flow and parallel flow heat exchangers.

Review and Analysis of Cross Flow Heat Exchanger Transient Modeling for Flow Rate and Temperature Variations

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Tianyi Gao ◽  
James Geer ◽  
Bahgat Sammakia
Keyword(s):  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Transient Response ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Inlet Temperature ◽  
Flow Rate Change ◽  
Flow Heat

Heat exchangers are important facilities that are widely used in heating, ventilating, and air conditioning (HVAC) systems. For example, heat exchangers are the primary units used in the design of the heat transfer loops of cooling systems for data centers. The performance of a heat exchanger strongly influences the thermal performance of the entire cooling system. The prediction of transient phenomenon of heat exchangers is of increasing interest in many application areas. In this work, a dynamic thermal model for a cross flow heat exchanger is solved numerically in order to predict the transient response under step changes in the fluid mass flow rate and the fluid inlet temperature. Transient responses of both the primary and secondary fluid outlet temperatures are characterized under different scenarios, including fluid mass flow rate change and a combination of changes in the fluid inlet temperature and the mass flow rate. In the ε-NTU (number of transfer units) method, the minimum capacity, denoted by Cmin, is the smaller of Ch and Cc. Due to a mass flow rate change, Cmin may vary from one fluid to another fluid. The numerical procedure and transient response regarding the case of varying Cmin are investigated in detail in this study. A review and comparison of several journal articles related to the similar topic are performed. Several sets of data available in the literatures which are in error are studied and analyzed in detail.

scholarly journals Experimental Investigation on Triple Concentric Tube Heat Exchanger with Helical Baffles

2020 ◽  
Vol 6 (11) ◽  
pp. 14-20
Author(s):  
Rohit Kumar Gaur ◽  
Dr. Shashi Kumar Jain ◽  
Dr. Sukul Lomash
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Solid Particles ◽  
Tube Heat Exchanger ◽  
High Heat Transfer

A heat exchanger is a device used to transfer thermal energy between two or more liquids, between a solid surface and a liquid, or between solid particles and a liquid at different temperatures and in thermal contact where shell and tube heat exchangers contain a large number of tubes packed in a jacket whose axes are parallel to those of the shell. Heat transfer occurs when one fluid flows into the pipes while the other flows out of the pipes through the jacket. In industry, three-tube heat exchanger tubes are used as condensers, evaporators, sub cooler, heat recovery heat exchangers, etc. The three concentric tube heat exchanger is a constructively modified version of the double concentric tube heat exchanger as an intermediate tube adds some advantages over the double tube heat exchangers in that it is larger tube surface area heat transfer per unit of length.  In the present study, the triple tube heat exchanger is further modified by inserting helical baffle over the surface of one of the tubes and observed turbulence flow which may lead to high heat transfer rates between the fluids of heat exchanger. Further, the Reynolds number, Nusselt number, friction factor of the flow at different mass flow rates of the hot fluid while keeping a constant mass flow rate of cold and normal temperature fluids were calculated. It was found that as the mass flow rate of the fluid increases the Reynolds number increases, the turbulence in the flow will increase which will cause the intermixing of the fluid, higher the rate of intermixing, more will be the heat transfer of the system.  

scholarly journals Experimentation on Augmenting Heat Transfer Characteristics of (Ethylene Glycol + Water) Mixture in A Combined (Pipe in Pipe and Shell & Tube) Heat Exchanger

2019 ◽  
Vol 8 (3) ◽  
pp. 4442-4449
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Working Fluid ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient

In this research work, the design of pipe in pipe, shelland-tube and combined heat exchanger (previously mentioned types were combined to consider as one unit) has been made. These three heat exchangers have been utilized for two kinds of flows i.e., parallel as well counter flow types individually. The design of combined heat exchanger takes been proposed with the idea of increasing the heat transfer area and to understand the behavior of various parameters involved by comparing with the individual heat exchangers. 75:25 aqueous Ethylene Glycols, have been used as the working fluid in all three heat exchangers of counter as well parallel flow conditions. Total quantity of working fluid is 12 liters, in which 6liters of fluid is used as cold fluid and the other half is used as hot fluid. As a result, overall heat transfer coefficient (U) has been increased with increase of mass flow rate. Highest overall heat transfer coefficient value observed as 1943w/m2 -k at highest mass flow rate (within the considerations of this work) of 0.145 kg/s. The highest decrement in LMTD recorded for 0.0425 to 0.145 increase of mass flow rate is 49.32% in shell-and-tube heat exchanger of parallel flow arrangement. The highest effectiveness is observed for pipe in pipe counter flow heat exchanger case, which is 0.39 at a mass flow rate of 0.145kg/s.

scholarly journals Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): sensitivity analysis on the Newberry volcanic setting

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hannah R. Doran ◽  
Theo Renaud ◽  
Gioia Falcone ◽  
Lehua Pan ◽  
Patrick G. Verdin
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Energy Flow ◽  
Closed Loop ◽  
Working Fluid ◽  
Valuable Insight ◽  
Deep Borehole

AbstractAlternative (unconventional) deep geothermal designs are needed to provide a secure and efficient geothermal energy supply. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as the working fluid mass flow rate, the casing and cement thermal properties, and the wellbore radii dimensions. The results conclude the highest energy flow rate to be 1.5 MW, after an annulus radii increase and an imposed mass flow rate of 5 kg/s. At 3 kg/s, the DBHE yielded an energy flow rate a factor of 3.5 lower than the NWG 55-29 conventional design. Despite this loss, the sensitivity analysis allows an assessment of the key thermodynamics within the wellbore and provides a valuable insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of subcritical conditions, and could aid the development of unconventional designs within future EGS work like the Newberry Deep Drilling Project (NDDP). Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems to support EGS projects that could extend to deeper depths.

scholarly journals An experimental study of the thermal performance of the square and rhombic solar collectors

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 487-494 ◽  
Author(s):  
Aminreza Noghrehabadi ◽  
Ebrahim Hajidavaloo ◽  
Mojtaba Moravej ◽  
Ali Esmailinasab
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Solar Collectors ◽  
Heating Systems ◽  
Solar Water Heating

Solar collectors are the key part of solar water heating systems. The most widely produced solar collectors are flat plate solar collectors. In the present study, two types of flat plate collectors, namely square and rhombic collectors are experi?mentally tested and compared and the thermal performance of both collectors is investigated. The results show both collectors have the same performance around noon (?61%), but the rhombic collector has better performance in the morning and afternoon. The values for rhombic and square collectors are approximately 56.2% and 53.5% in the morning and 56.1% and 54% in the afternoon, respectively. The effect of flow rate is also studied. The thermal efficiency of rhombic and square flat plate collectors increases in proportion to the flow rate. The results indicated the rhombic collector had better performance in comparison with the square collector with respect to the mass-flow rate.

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