scholarly journals A Model of Heat Transfer in Counter-Current Heat Exchanger with a Thermoelectric Cooling Element

2019 ◽  
Author(s):  
IGOR BATARONOV ◽  
ALEXANDER KRETININ ◽  
VLADIMIR SELIVANOV ◽  
EKATERINA SPYTSINA ◽  
TATJANA NADEINA
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermoelectric Cooling ◽  
Cooling Element ◽  
Counter Current ◽  
Current Heat

A Novel Gas-Water Heat Exchanger With Minichannels

2008 ◽  
Author(s):  
Yang Chen ◽  
Per Lundqvist ◽  
Bjo¨rn Palm
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Low Pressure ◽  
Shell Side ◽  
Hot Air ◽  
Drop Flow ◽  
Counter Current ◽  
Good Heat ◽  
Current Heat

In the current study, a novel gas water heat exchanger with minichannels is designed, built and tested. The heat exchanger is mainly composed of a number of concentric ring shaped plates, which are made up of several heat exchanger tubes. The ring shaped plates are arranged in parallel and placed in a shell. The heat exchanger is designed as a counter current heat exchanger with laminar flow on the heat exchanger’s shell-side (gas side) and therefore has a very low pressure drop on the shell side. The heat exchanger was tested with water and hot air on its tube-side and shell-side respectively. All the necessary parameters like inlet and outlet temperatures on tube-side and shell-side as well as the pressure drop, flow rate of fluids, etc. were measured. Different existing correlations were used to calculate the overall heat transfer coefficient and the results were compared with the measured value. The measured results show that the new designed heat exchanger can achieve a good heat transfer performance and also maintain a low pressure drop on shell-side (gas side).

A numerical analysis of heat transfer in a cross-current heat exchanger with controlled and newly designed air flows

2018 ◽  
Vol 16 (1) ◽  
pp. 627-636 ◽  
Author(s):  
Witold Żukowski ◽  
Przemysław Migas ◽  
Monika Gwadera ◽  
Barbara Larwa ◽  
Stanisław Kandafer
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flow Resistance ◽  
Substantial Part ◽  
Fluidised Bed ◽  
Air Chamber ◽  
Model Variant ◽  
Counter Current ◽  
Cross Current ◽  
Current Heat

AbstractSimulations of heat transfer between air and flue gases in a plate heat exchanger are presented. The device was designed for the heating of the air supplying a fluidised furnace for the combustion of wet sludge and wood crumbs. The locations of inlets and outlets and the geometry of the heat exchanger are determined by the construction of the furnace. The aim of the simulations was to increase effectiveness of heat transfer through the use of flow redirections with additional baffles placed in the air chamber. The results of the simulations showed that a substantial part of the heat exchanger without baffles is not used effectively. On the basis of a velocity profile, a temperature distribution and a wall heat flux, the geometry of the inter-plate space within the air chamber was modified by adding baffles. The unmodified exchangers had 77% efficiency in comparison to counter-current exchangers with the same heat transfer area. After the application of baffles, the efficiency increased to 83-91% depending on the construction used (one, two or three baffles). The best model variant of the exchanger with baffles led to the increase in the temperature of air supplying the fluidised bed by approximately 76 K in relation to the system without baffles . Unexpectedly, the presented modifications of the geometry of the system had very low influence of the flow resistance in the air chamber. The value of Δp for the system without baffles is almost the same as for the best model variant.

Vascular Anatomy of the Counter-Current Heat Exchanger of Skipjack Tuna

1974 ◽  
Vol 61 (1) ◽  
pp. 145-153 ◽  
Author(s):  
E. DON STEVENS ◽  
HOW MAN LAM ◽  
J. KENDALL
Keyword(s):  
Heat Transfer ◽  
Blood Flow ◽  
Heat Exchanger ◽  
Vascular Anatomy ◽  
Dorsal Aorta ◽  
Gas Transfer ◽  
Skipjack Tuna ◽  
Cardinal Vein ◽  
Counter Current ◽  
Current Heat

1. The anatomy of the counter-current heat exchanger of skipjack tuna is described and the pattern of blood flow is analysed. 2. The pattern of blood flow is from the dorsal aorta, through the exchanger to segmental arteries to the tissues, from the tissues to segmental veins and back through the exchanger to the post-cardinal vein. 3. The vessels in the exchanger are about the same size as systemic arterioles and venules and are about 10 mm long. There are about 125000 of each type in a 2 kg tuna. 4. The velocity of blood flow in the exchanger is about 1/80th of that in the dorsal aorta and post-cardinal vein allowing time for heat transfer. 5. There are many valves in the segmental veins which may be expected because of the resistance offered by the exchanger. 6. The vessels in the tuna heat exchanger are an order of magnitude larger than those in the swim-bladder rete, thus permitting heat transfer but preventing gas transfer.

scholarly journals PDE Observer Design for Counter-Current Heat Flows in a Heat-Exchanger

2017 ◽  
Vol 50 (1) ◽  
pp. 7127-7132 ◽  
Author(s):  
Fairouz Zobiri ◽  
Emmanuel Witrant ◽  
François Bonne
Keyword(s):  
Heat Exchanger ◽  
Observer Design ◽  
Heat Flows ◽  
Counter Current ◽  
Current Heat

scholarly journals The effect of meal temperature on heart rate in Rhodnius prolixus

2019 ◽  
Author(s):  
Chloé Lahondère ◽  
Maurane Buradino ◽  
Claudio R. Lazzari
Keyword(s):  
Heart Rate ◽  
Heat Exchanger ◽  
Rhodnius Prolixus ◽  
List Type ◽  
Meal Intake ◽  
Warm Blood ◽  
Counter Current ◽  
The Impact ◽  
Current Heat

AbstractRhodnius prolixus is able to cool down the ingested blood during feeding on a warm-blooded host. This is possible because of a counter-current heat exchanger located in its head, which transfers heat from the warm blood to the insect haemolymph and can dissipate through the head cuticle. Given the key role haemolymph circulation in thermoregulation, we investigated the modulation of the activity of the heart during the warmed meal intake. We evaluated the impact of meal temperature on the heart rate and found that feeding led to an increase in the frequency of heart contractions, which increases with increasing food temperature. We also found that females have a higher heart rate during feeding compare to males.HIGHLIGHTSFeeding increases the heart rate of Rhodnius prolixusThe higher the meal temperature, the higher the heart rate becomesFemales have a higher heart rate than males

scholarly journals RESEARCH OF THE FUNCTIONING AND OPTIMIZATION PROCESS OF THE STRUCTURAL-TECHNOLOGICAL PARAMETERS

2020 ◽  
pp. 142-150
Author(s):  
Vitaliy Yaropud
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flow Rate ◽  
Thermal Power ◽  
Design Parameters ◽  
Theoretical Studies ◽  
Technological Parameters ◽  
Air Flows ◽  
Counter Current ◽  
Pipe Heat

Domestic and foreign scientists in recent years have performed a considerable amount of scientific research on the biological justification of optimal combinations of microclimate parameters required for the normal development of animals. However, the results of the studies do not allow one to specify the optimal parameters for different species of animals, taking into account their age, sex, weight and level of feeding. While it is possible to specify rather wide limits of change of temperature and relative humidity of air at which productivity is maximum, and technical and economic efficiency is approximately the same. Providing microclimate regulations in livestock premises is associated with significant costs of electricity and heat, which is about 17% of the producers' costs. To create a microclimate in livestock premises based on the above technological parameters and the analysis of the design features of the recuperators, two design and technological schemes of the three-pipe recuperator, which differ in the directions of movement of air flows, are proposed. The purpose of the research is to increase the efficiency of the technological process of functioning of the three-pipe recuperator for livestock premises by substantiating its structural and mode parameters. The results of theoretical studies of pneumatic losses in the three-pipe recuperator determined the dependence of pressure and power losses on the length of the air duct of the three-pipe recuperator, the radius of the external duct and the volume flow rate of air. As a result of theoretical studies, a mathematical model of the heat transfer process in a three-pipe heat exchanger was developed, with condensation in it, which allows to determine the temperature distribution of air flows by its length and its thermal capacity. The results of theoretical studies of the process of heat transfer in the design and technological schemes of a three-pipe recirculator with counter-current and direct-current showed that the counter-current variant is more effective. Optimization of the results of theoretical studies allowed us to determine the dependence of the design parameters of the three-pipe heat exchanger on the volumetric flow rate of air, subject to the highest useful thermal power.

Poisson Conduction Shape Factors for “Mixed Case” Counter-Current Heat Transfer Applications

2004 ◽  
Author(s):  
Devashish Shrivastava ◽  
Robert B. Roemer
Keyword(s):  
Heat Transfer ◽  
Vessel Wall ◽  
Source Term ◽  
The Other ◽  
Tissue Temperature ◽  
Shape Factors ◽  
Mixed Case ◽  
Boundary Temperature ◽  
Counter Current ◽  
Current Heat

The effects of a source term and geometry on vessel-vessel and vessel-tissue Poisson conduction shape factors (VVPCSFs and VTPCSFs) are studied for uniformly heated, finite, non-insulated tissues for the ‘mixed case’ i.e., when the tissue boundary temperature lies in between the two vessel wall temperatures. In addition, two alternative formulations for the VTPCSFs are compared; while both formulations use the vessel wall temperature, one uses the tissue boundary temperature, and the other the area averaged tissue temperature. Results show that the VVPCSFs are only geometry dependent and do not depend on the applied power or the two vessel wall and tissue boundary temperatures. Conversely, the VTPCSFs are strong functions of these variables.

Heat exchange in relation to blood flow between thorax and abdomen in bumblebees

1976 ◽  
Vol 64 (3) ◽  
pp. 561-585
Author(s):  
B. Heinrich
Keyword(s):  
Blood Flow ◽  
Heat Exchanger ◽  
Heart Beat ◽  
Thoracic Temperature ◽  
Wide Range ◽  
Narrow Passage ◽  
Switch Mechanism ◽  
Low Amplitude ◽  
Counter Current ◽  
Current Heat

1. The narrow passage within the petiole between thorax and abdomen is anatomically constructed so that counter-current exchange should retain heat in the thorax despite blood flow to and from the cool abdomen. 2. However, the counter-current heat exchanger can be physiologically circumvented. Exogenously heated bumblebees prevented overheating of the thorax by shunting heat into the abdomen. They also regurgitated fluid, which helped to reduce head temperature but had little effect on thoracic temperature. 3. Temperature increases in the ventrum of the abdomen occurred in steps exactly coinciding with the beats of the ventral diaphragm, and with the abdominal ‘ventilatory’ pumping movements when these were present. The ability to prevent overheating of the thorax by transport of heat to the abdomen was abolished when the heart was made inoprative. 4. At low thoracic temperatures the ventral diaphragm beat at a wide range or rates and with varying interbeat intervals, while the heart beat at a high frequency relative to the ventral diaphragm, but at a very low amplitude. However, when thoracic temperature exceeded 43 degrees C the amplitudes of both were high, and the interbeat intervals as well as the beating frequencies of the two pulsatile organs became identical in any one bee. Furthermore, heated bees engaged in vigorous abdominal pumping at the same frequency as that of their heart and ventral diaphragm pulsations. 5. The results indicate that the anatomical counter-current heat exchanger is reduced or eliminated during heat stress by ‘chopping’ the blood flow into pulses, and the blood pulses are shunted through the petiole alternately by way of a switch mechanism.

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