scholarly journals Extrusion Characteristics of Thin Walled Tubes for Catheters Using Thermoplastic Elastomer

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1628
Author(s):  
Soonmo Cho ◽  
Euntaek Lee ◽  
Seunggi Jo ◽  
Gyu Man Kim ◽  
Woojin Kim
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Wall Thickness ◽  
Flow Rate ◽  
High Performance ◽  
Thermoplastic Elastomer ◽  
Air Pressure ◽  
Outer Diameter ◽  
Screw Speed ◽  
Thin Walled

As the market for minimally invasive surgery has grown, the demand for high-precision and high-performance catheters has increased. Catheters for the diagnosis and treatment of cardiovascular or cerebrovascular disease mainly use a braided wire tube with a polymer inner liner and outer jacket to improve the pushability and trackability. The outer jacket should have an accurate inner and outer diameter and while maintaining a wall thickness of 150 µm or less. In this study, we designed and manufactured a tip and die capable of extruding an outer jacket with a wall thickness of 150 µm or less using a medical thermoplastic elastomer for manufacturing 8Fr (2.64 mm diameter) thin-walled tubes. The ovality and inner/outer diameters of the tube were studied according to changes in the screw speed (mass flow rate), puller speed, air pressure applied to the lumen, and distance between the quench and head, which are the main variables of microextrusion processes. The screw speed (mass flow rate), puller speed, and air pressure affected the inner/outer diameter of the tube, with screw speed and puller speed having the largest influence on diameter. The air pressure and distance between quench and head had the greatest influence on ovality. The results show the effect of different processing parameters on the characteristics of the extruded tube, which will help to establish a stable extrusion process for the manufacture of outer jackets for braided catheter shafts.

Analysis and Optimization of Steam Duct for Improving Performance of Steam Cleaner

2012 ◽  
Vol 195-196 ◽  
pp. 52-55
Author(s):  
Jian Hua Wang ◽  
Yun De Shen ◽  
Dong Ji Xuan ◽  
Tai Hong Cheng ◽  
Zhen Zhe Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Quadratic Programming ◽  
Numerical Method ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Optimization Algorithm ◽  
Sequential Quadratic Programming ◽  
High Performance

Not only the price of a steam cleaner but also the performance of it should be considered to improve the competitive power of the products. In this study, a steam duct was optimized by changing the length of guide line for compensating the drawback of the unbalanced mass flow rate of steam from each outlet. For evaluating the mass flow rate of each outlet, a commercial CFD(computational fluid dynamics) code was used. In the process of the optimization, SQP(sequential quadratic programming) optimization algorithm was applied. The numerical method in this study can be widely used to develop a high performance domestic steam cleaner.

Experimental Investigation on Cryogenic Line Chill-Down Process by Using Liquid Nitrogen

2016 ◽  
Author(s):  
Lingxue Jin ◽  
Mansu Seo ◽  
Hyokjin Cho ◽  
Changgi Park ◽  
Cheonkyu Lee ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Liquid Nitrogen ◽  
Mass Flow ◽  
Flow Rate ◽  
Cryogenic Liquid ◽  
Transient Temperature ◽  
Outer Diameter ◽  
Horizontal Pipe ◽  
Pressure Profiles ◽  
Pipe Line

Generally, a part of transporting liquids are used as the coolant to chill down the transfer line. Minimizing the line chill-down time and the consumption of the cryogenic propellant during the line chill-down is a mainly concerned issue. In this study, the cryogenic line chill-down experiments are conducted on a 12.7 mm outer diameter, 1.25 mm wall thickness and 7 m long stainless steel horizontal pipe with liquid nitrogen (LN2) injection. The pipe is vacuum jacketed to reduce the heat inleak from room temperature to the cryogenic liquid. The temperature and the pressure profiles of the chill-down line are obtained at the location 6 meters away from the pipe inlet under various mass flow rates. The history of the transient temperature, the pressure and the mass flow rate during the line chill-down process are monitored for various cases. The relationship between the line chill-down time and the mass flow rate is analyzed and presented for one representative pipe line geometry.

Numerical Research of Aerodynamic Sweep on Leading Edge in the Ram-Rotor

2017 ◽  
Author(s):  
Jian Guan ◽  
Ji-ang Han ◽  
Jingjun Zhong ◽  
Chenguang Yuan
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Performance ◽  
Pressure Ratio ◽  
Leading Edge ◽  
High Mass ◽  
Positive Role ◽  
Performance Curves ◽  
Flow Loss

In order to diminish the flow loss in the ram-rotor and improve its aerodynamic performance, the effect of forward and backward swept leading edge on flow field and shock pattern in the ram-rotor was investigated using 3-dimensional steady CFD. Ram-rotors with sweeping angles of −60°, −30°, −15°, 0°, 15°, 30°, 60° were modeled, and ram-rotor performance, shock pattern and leakage flow in different swept schemes were the main focuses of attention. The effect of sweeping angle was also discussed in this paper. It has been found that forward sweep makes performance curves move to high mass flow rate zone in the performance map. Meanwhile, strake tip loading decreases, and maximum adiabatic efficiency increases by 0.31% compared to baseline ram-rotor. Contrary to the forward swept scheme, performance curves of backward sweep schemes shift to small mass flow rate zone, and the tip leakage near front part of strake is enhanced. Backward sweep plays a positive role in improving pressure ratio with a maximum increment of 0.46% at peak efficiency point, but causes a high flow loss. As sweeping angle changes, there is an optimum angle value to get a high performance.

scholarly journals Gas Turbine Tubular Combustor Main Injector Optimization for Low Emission Combustion

2018 ◽  
Vol 26 (10) ◽  
pp. 1-12
Author(s):  
Arkan Khikhal Husain ◽  
Mahmood Attallah Mashkoor ◽  
Fuad Abdul Ameer Khalaf
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Performance ◽  
Atmospheric Conditions ◽  
Air Mass ◽  
Fuel Flow ◽  
Low Emission ◽  
Gas Fuel

This work presents the experimental investigation results of high performance and low emission colorless combustion in a gas turbine tubular combustor at atmospheric conditions. Low emission and colorless oxidation reaction is characterized by dispersed flame and temperature under the conditions of preheated air. System performance, emissions of CO and UHC are recorded up to achieve low emission colorless combustion, the flame capturing, Measurements of temperature, inlet air mass flow rate and gas fuel LPG flow rate for variable of fuel main injector holes diameter. concluded that maximal air mass flow rate, with choked fuel flow in the main injector for each cases promotes the formation of colorless pal blue flame combustion, for 3.2 g/s of fuel flow rate with 6 holes and 1mm main injector holes diameter and lower CO emissions and decreasing in UHC emissions (70 → 10) ppmv with increasing in power generation (0.5 → 3.42) kW and decreasing in S.F.C. (21.5 → 3.49) kg/kwh.

scholarly journals Effects of Extrusion Conditions on Physical Properties of Sorghum Based Extruded Products

2021 ◽  
pp. 18-26
Author(s):  
Byreddy Naveena ◽  
Mohan Singh
Keyword(s):  
Moisture Content ◽  
Physical Properties ◽  
Bulk Density ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Screw Speed ◽  
Blend Ratio ◽  
High Temperature Short Time ◽  
Extruded Products

Extrusion cooking is a high temperature short time multivariable unit operation. In this study, response surface methodology (RSM) was used to evaluate the effect of feed parameters i.e., feed moisture (8-16%), blend ratio of sorghum:barley:bengal gram, (70:15:15 to 50:35:15) and machine parameters of twin screw extruder i.e., barrel temperature (120-200oC) and screw speed (120-200 rpm) on physical properties of extrudates i.e., mass flow rate, bulk density and moisture content. The results showed that maximum mass flow rate (0.974 g/s) was observed with the blend ratio 60:25:15, having 8 percent moisture (w.b) extruded at 160oC barrel temperature and a screw speed of 160 rpm. The bulk density of extrudates was found minimum (0.08 g/cc) at 10% moisture content, 65:20:15 blend ratio, 180oC barrel temperature and 180 rpm screw speed and the moisture content of extrudates was found minimum (4.74%) at 10% moisture content, 55:30:15 blend ratio, 180oC barrel temperature and 140 rpm screw speed.

scholarly journals Evaluation of flowability for granulated powder using a test of powder discharge by pressurized air

2021 ◽  
Vol 249 ◽  
pp. 08001
Author(s):  
Koichiro Ogata ◽  
Daigo Ariga
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Bond Number ◽  
Air Pressure ◽  
Particle Sizes ◽  
Powder Bed ◽  
Pressure Region ◽  
Separation Force ◽  
The Relationship

This study experimentally and theoretically examined the flowability and the cohesiveness for powder using a test of powder discharge through an orifice by the pressurized air. The powder used consisted of two kinds of Calcium hydroxide which have different particle sizes by granulation. These sizes are 11µm and 176µm, those called Ca(OH)2 -A and -B. Cohesiveness is characterized by the Bond number which is the ratio of separation force to the gravity force. Flowability is evaluated by the relationship between the mass flow rate and the average air pressure acting on the powder bed. We found that the Bond number of Ca(OH)2 -B was much lower than Ca(OH)2 -A. The relation between the mass flow rate of the powder and the average air pressure indicates Ca(OH)2 -B is easily flowing at the lower pressure region, and Ca(OH)2 -A was scattered at the higher pressure region. This means Ca(OH)2 -B has good flowability by the particle granulation in comparison with Ca(OH)2 -A.

The standard unit mass flow rate of gas-liquid mixtures

2020 ◽  
pp. 13-16
Author(s):  
V.N. Petrov ◽  
◽  
V.F. Sopin ◽  
L.A. Akhmetzyanova ◽  
Ya.S. Petrova ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Liquid Mixtures ◽  
Unit Mass ◽  
Standard Unit

Prediction of Leakage Mass Flow Rate Through Gas Springs

1987 ◽  
Author(s):  
Roberto Bruno Bossio ◽  
Vincenzo Naso ◽  
Marian Cichy ◽  
Boleslaw Pleszewski
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate
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