Improved Ease of Use Designs for Rapid Heart Cooling

2012 ◽  
Vol 6 (3) ◽  
Author(s):  
Thomas L. Merrill ◽  
Denise R. Merrill ◽  
Jennifer E. Akers
Keyword(s):  
Pressure Difference ◽  
Cooling System ◽  
Cooling Capacity ◽  
Heart Tissue ◽  
Ease Of Use ◽  
Swine Model ◽  
Animal Testing ◽  
Attack Model ◽  
External Cooling ◽  
Cooling Design

Mild hypothermia has been shown to reduce heart tissue damage resulting from acute myocardial infarction (AMI). In previous work we developed a trilumen cooling catheter to deliver cooled blood rapidly to the heart during emergency angioplasty. This paper describes two alternative designs that seek to maintain tissue cooling capability and improve “ease of use.” The first design was an autoperfusion design that uses the natural pressure difference between the aorta and the coronary arteries to move blood through the trilumen catheter. The second design used an external cooling system, where blood was cooled externally before being pumped to the heart through a commercially available guide catheter. Heat transfer and pressure drop analyses were performed on each design. Both designs were fabricated and tested in both in vitro and in vivo settings. The autoperfusion design did not meet a cooling capacity target of 20 W. Animal tests, using swine with healthy hearts, showed that the available pressure difference to move blood through the trilumen catheter was approximately 5–10 mmHg. This differential pressure was too low to motivate sufficient blood flow rates and achieve the required cooling capacity. The external cooling system, however, had sufficient cooling capacity and reasonable scalability. Cooling capacity values varied from 14 to 56 W over a flow range of 30–90 ml/min. 20 W and 30 W were achieved at 38 ml/min and 50 ml/min, respectively. Animal testing showed that a cooling capacity of 30 W delivered to the left anterior descending (LAD) and left circumflex arteries (LCX) of a healthy 70 kg swine can reduce heart tissue temperatures rapidly, approximately 3 °C in 5 min in some locations. Core temperatures dropped by less than 0.5 °C during this cooling period. An autoperfusion design was unable to meet the target cooling capacity of 20 W. An external cooling design met the target cooling capacity, providing rapid (1 °C/min) localized heart tissue cooling in a large swine model. Future animal testing work, involving a heart attack model, will investigate if this external cooling design can save heart tissue.

Design of a Cooling Guide Catheter for Rapid Heart Cooling

2010 ◽  
Vol 4 (3) ◽  
Author(s):  
Thomas L. Merrill ◽  
Denise R. Merrill ◽  
Todd J. Nilsen ◽  
Jennifer E. Akers
Keyword(s):  
Heart Attack ◽  
Mild Hypothermia ◽  
Circulatory System ◽  
The United States ◽  
Cooling Capacity ◽  
Heart Tissue ◽  
Animal Testing ◽  
Local Cooling ◽  
Mock Circulatory System ◽  
Guide Catheter

Cardiovascular disease is the leading cause of death in the United States. Despite decades of care path improvements approximately 30% of heart attack victims die within 1 year after their first heart attack. Animal testing has shown that mild hypothermia, reducing tissue temperatures by 2–4°C, has the potential to save heart tissue that is not adequately perfused with blood. This paper describes the design of a cooling guide catheter that can provide rapid, local cooling to heart tissue during emergency angioplasty. Using standard materials and dimensions found in typical angioplasty guide catheters, a closed-loop cooling guide catheter was developed. Thermal fluid modeling guided the interior geometric design. After careful fabrication and leak testing, a mock circulatory system was used to measure catheter cooling capacity. At blood analog flow rates ranging from 20 ml/min to 70 ml/min, the corresponding cooling capacity varied almost linearly from 20 W to 45 W. Animal testing showed 18 W of cooling delivered by the catheter can reduce heart tissue temperatures rapidly, approximately 3° in 5 min in some locations. Future animal testing work is needed to investigate if this cooling effect can save heart tissue.

A simplified method of temperature control maximizing productivity of the batch reactor; The effect of inertia of the cooling system

1982 ◽  
Vol 47 (2) ◽  
pp. 454-464 ◽  
Author(s):  
František Jiráček ◽  
Josef Horák
Keyword(s):  
Mathematical Model ◽  
Temperature Control ◽  
Cooling System ◽  
Batch Reactor ◽  
Exothermic Reaction ◽  
Cooling Capacity ◽  
Variable Activity ◽  
Simplified Method ◽  
Opening And Closing ◽  
Time Of Operation

The effect has been studied of the inertia of the cooling system on the reliability of control of the temperature of the reaction mixture. The study has been made using a mathematical model of the batch reactor with an exothermic reaction. The temperature has been controlled by a two-level controller opening and closing the flow of the coolant. The aim of the control has been to maintain a constant value of the degree of utilization of the cooling capacity of the reactor. The instantaneous value of the degree of utilization has been assessed from the ratio of times for which the cooling system is idle to the time of operation. The reliability of control has been studied for variable activity of the catalyst.

Rechargeable Personal Air Conditioning Device

2016 ◽  
Author(s):  
Yilin Du ◽  
Jan Muehlbauer ◽  
Jiazhen Ling ◽  
Vikrant Aute ◽  
Yunho Hwang ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Cooling Capacity ◽  
Comfort Level ◽  
Vapor Compression ◽  
Air Conditioning System ◽  
System A ◽  
Single Person ◽  
Vapor Compression Cycle ◽  
Compression Cycle

A rechargeable personal air-conditioning (RPAC) device was developed to provide an improved thermal comfort level for individuals in inadequately cooled environments. This device is a battery powered air-conditioning system with the phase change material (PCM) for heat storage. The condenser heat is stored in the PCM during the cooling operation and is discharged while the battery is charged by using the vapor compression cycle as a thermosiphon loop. The conditioned air is discharged towards a single person through adjustable nozzle. The main focus of the current research was on the development of the cooling system. A 100 W cooling capacity prototype was designed, built, and tested. The cooling capacity of the vapor compression cycle measured was 165.6 W. The PCM was recharged in nearly 8 hours under thermosiphon mode. When this device is used in the controlled built environment, the thermostat setting can be increased so that building air conditioning energy can be saved by about 5–10%.

A Numerical Analysis on the System Impedance in a Fan Cooling System

2003 ◽  
Author(s):  
Dong-Il Kim ◽  
Ki-So Bok ◽  
Han-Bae Lee
Keyword(s):  
Numerical Analysis ◽  
Pressure Drop ◽  
Flow Rate ◽  
Pressure Difference ◽  
Cooling System ◽  
Computational Time ◽  
Computational Domain ◽  
Impedance Curve ◽  
Fan Cooling ◽  
Large Investment

To seek the fan operating point on a cooling system with fans, it is very important to determine the system impedance curve and it has been usually examined with the fan tester based on ASHRAE standard and AMCA standard. This leads to a large investment in time and cost, because it could not be executed until the system is made actually. Therefore it is necessary to predict the system impedance curve through numerical analysis so that we could reduce the measurement time and effort. This paper presents how the system impedance curve (pressure drop curve) is computed by CFD in substitute for experiment. In reverse order to the experimental principle of the fan tester, pressure difference was adopted first as inlet and outlet boundary conditions of the system and then flow rate was calculated. After determining the system impedance curve, it was compared with experimental results. Also the computational domain of the system was investigated to minimize computational time.

scholarly journals Application of Ultrasonic Atomization in a Combined Circulation System of Spray Evaporative Cooling and Air Cooling for Electric Machines

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1773
Author(s):  
Yu Wang ◽  
Lin Ruan
Keyword(s):  
Cooling System ◽  
Evaporative Cooling ◽  
Convection Heat Transfer ◽  
Cooling Capacity ◽  
Circulation System ◽  
Air Cooling ◽  
Test Model ◽  
Ultrasonic Atomization ◽  
System A ◽  
Air Circulation

A combined circulation system of spray evaporative cooling and air cooling (CCSSECAC) is a way to enhance the cooling performance of an air-cooled electric machine while maintaining its existing structure. Based on a traditional air-cooled machine, when the discrete evaporative cooling medium particles are scattered into the airflow, they will reach the heat source with the air circulation. The cooling capacity of the cooling system is enhanced simultaneously through the phase transition and convection heat transfer. Ultrasonic atomization is a simple way to produce tiny droplets and a good way to improve the performance of CCSSECAC. To verify the effectiveness of such a system, a principle test model was built and a multi-operational condition experiment was carried out as an exploratory study. The experimental results showed that the new cooling system was feasible for horizontal machines, and the stator coil temperature was significantly reduced compared with the air-cooled mode.

Plastic pipe solidification in extrusion

2018 ◽  
Vol 38 (6) ◽  
pp. 591-603
Author(s):  
Pongthep Poungthong ◽  
Chanyut Kolitawong ◽  
Chaimongkol Saengow ◽  
Alan Jeffrey Giacomin
Keyword(s):  
Residual Stress ◽  
Cooling System ◽  
Outer Wall ◽  
Solidification Time ◽  
Solidification Temperature ◽  
Pipe Surface ◽  
Plastic Pipe ◽  
External Cooling ◽  
Wall Boundary Conditions ◽  
Pipe Extrusion

AbstractIn plastic pipe extrusion, hot molten extrudate emerges from an annular. This highly viscous liquid is then cooled and solidified, calledquenching, in a quench tank. In this paper, we focus on the external cooling system. We use an adiabatic inner wall and differing outer wall boundary conditions: isothermal and convection. The solid-liquid interface, at the solidification temperature, moves inward with deceleration. We adimensionalize the energy balance and solve for the interface speed in terms of the solidifcation coefficient,λ. We arrive at the exact solutions for the evolving solidified thickness. Finally, we use the residual stress model developed by Jansen [Int. Polym. Proc. 1994, 9, 82–89]. to predict the compressive residual stress at the outer pipe surface. Our new exact solution for the solidification time agrees well with the data from the plastic pipe industry. The goals of this paper are to help plastics engineers calculate the solidification time, to design the cooling chamber and to predict the residual quenching stress.

Experimental Study of Capillary Radiant Cooling System with Parameters Changing

2013 ◽  
Vol 300-301 ◽  
pp. 1048-1053 ◽  
Author(s):  
Yong Hong Wang
Keyword(s):  
Room Temperature ◽  
Cooling System ◽  
Cooling Capacity ◽  
Test Methods ◽  
Radiation Response ◽  
Volume Changes ◽  
Indoor Temperature ◽  
Radiant Cooling ◽  
Radiation Laboratory ◽  
The Impact

In this paper, the test methods of radiation laboratory and data analysis in detail were introduced. The impact of the capillary system with different parameters changing, such as water temperature or water flow the capillary cooling capacity changes, and the capillary cooling system when the initial radiation response time were specificially studied. Under different parameters while cooling capillary volume changes associated with the indoor temperature can be seen under certain conditions, the capillary cooling capacity and room temperature has a linear relationship.

scholarly journals The 701F Gas Turbine Design Process: Upgrade and Innovations

1999 ◽  
Author(s):  
B. Facchini ◽  
C. Carcasci ◽  
G. Ferrara ◽  
L. Innocenti ◽  
D. Coutandin ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Design Process ◽  
Cooling System ◽  
Design Procedure ◽  
Operating Conditions ◽  
Pollutant Emission ◽  
Inlet Section ◽  
Blade Cooling ◽  
Cooling Design ◽  
Power Capability

In this paper, a Fiat Avio 701F gas turbine re-design process is presented. This already tested gas turbine has been modified, for a particular re-powering application: a reduction in the net power production is required, whereas efficiency and exhaust temperature have been improved by mean of increased hot gas temperature at the first nozzle inlet section. Consequently this re-powering solution clearly requires consistent re-design efforts to satisfy specific plant operating conditions. The gas turbine power output has been tuned to the required value by reducing the air inlet mass flowrate; the combustion chamber setting has been modified with particular attention to the control of pollutant emission level. The increase of inlet stator turbine temperature necessitated a complete review of the three cooled turbine stages. The aim of greater overall efficiency with inlet and exit turbine temperature increase also involved the introduction of a new blade material. For design tool flexibility the blade cooling design procedure has been improved making better optimization of the cooling system possible. In this paper a detailed description of the several gas turbine modifications with particular attention to the blade cooling design procedure and to the corresponding simulation results is reported. The modifications developed could also be introduced on the new version of the 701F, at full power capability, in order to get better efficiency and power.

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