Spray Performances and Cryogenic Characteristics of C02 Snow under Cryosurgery Guided by Endoscopic

2014 ◽  
Vol 30 (3) ◽  
pp. 247-253
Author(s):  
T.-C. Lin ◽  
Y.-J. Shen ◽  
M.-R. Wang
Keyword(s):  
Cooling Rate ◽  
Design Parameter ◽  
Injection Pressure ◽  
Operation Time ◽  
Conversion Ratio ◽  
Main Flow ◽  
Cylinder Pressure ◽  
Bypass Flow ◽  
Impact Area ◽  
Effective Design

ABSTRACTThis research experimentally investigated effects of injection pressure, formation chamber and bypass flow on spray performances and cryogenic characteristics of CO2 snow under cryosurgery guided by endoscopic. Results show that CO2 snow has a superior freezing capability in the application of cryosurgery. The length of formation chamber is an effective design parameter to control spray performances and cryogenic characteristics. Increase in the length of formation chamber can increase snow size and conversion ratio, as well as the cooling rate and impact area of the tissue. Thus, it is suitable for the application on wider range nidus. Moreover, the bypass flow can efficiently modulate the cooling effect of the main flow with CO2 snow particles, and extend the operation time of cryosurgery. The experimental results also show that decrease the cylinder pressure, decrease the length of formation chamber, and increase the diameter of bypass apertures can slow down the flying velocity of CO2 snow which are effective methods to control the jet velocity and prevent the risk of penetration.

Development of Reformative Surgery Method Using Partial Freezing for the Liver

2006 ◽  
Vol 128 (6) ◽  
pp. 862-866
Author(s):  
M. Takahashi ◽  
S. Nomura ◽  
M. Jindai ◽  
S. Shibata ◽  
X. Zhu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Degrees Of Freedom ◽  
Operation Time ◽  
Basic Research ◽  
Freezing Temperature ◽  
The Finite Element Method ◽  
Porcine Liver ◽  
Liver Sample ◽  
Peltier Module ◽  
Increment Rate

To minimize surgical stresses including blood loss and operation time to the patients during hepatic resection, we studied the feasibility of a combination of a partial liver freezing technique and shape-memory alloy, which also enables a free-designed resection curve. In this surgical procedure, the region surrounding a tumor in the liver is frozen to excise and prevent hemorrhage. The liver was frozen by a Peltier module. The effects of cooling rate and freezing temperature on the excision force that arise between a scalpel and the liver are carried out experimentally as a basic research for partial freezing surgical procedures. A porcine liver was used as a liver sample. The physical properties were estimated by using the finite element method based on the heat transfer characteristics of the liver. Isolation of the liver was conducted using a scalpel attached to the end-effector of a 3 degrees of freedom robot. In the experiments, the minimum excision force was obtained at a temperature between 272K and 275K; therefore, it is preferable that the liver be excised within this temperature range. Lowering of the cooling rate decreases the excision force even if the temperature of the liver remains unchanged. The lower the temperature of the liver is, the larger the increment rate of excision force is with regard to the cooling rate.

Investigation on the combustion noise of a pilot-ignited direct-injection natural-gas engine

2016 ◽  
Vol 230 (14) ◽  
pp. 1942-1957 ◽  
Author(s):  
Menghan Li ◽  
Qiang Zhang ◽  
Guoxiang Li
Keyword(s):  
Natural Gas ◽  
Direct Injection ◽  
Injection Pressure ◽  
Pressure Level ◽  
Combustion Noise ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Engine Load ◽  
Gas Engine ◽  
Natural Gas Engine

In this paper, the effects of the injection timing, the injection pressure and the engine load on the combustion noise of a pilot-ignited direct-injection natural-gas engine were explored by analysing the separate components of the in-cylinder pressure. The results suggested that retarding the injection timing and reducing the injection pressure are effective ways of controlling the combustion noise. This can be attributed to the promoted burning rate at advanced injection timings and to the increased injection pressure. However, the effect of the engine load seems to be less obvious, although the resonance pressure level appears to increase with increasing engine load; the estimated combustion noise shows a decreasing tendency.

scholarly journals The Differential Impact of Various Injection Pressures on the Exergy of a Diesel Engine Using Biodiesel-Diesel Fuel Blends

2021 ◽  
Vol 14 (1) ◽  
pp. 345
Author(s):  
Mostafa Kiani Deh Kiani ◽  
Sajad Rostami ◽  
Gholamhassan Najafi ◽  
Mohamed Mazlan
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Diesel Fuel ◽  
Exergy Analysis ◽  
Direct Injection ◽  
Injection Pressure ◽  
Cylinder Pressure ◽  
Fuel Blends ◽  
Lack Of Information ◽  
Good Agreement

Contrary to energy, exergy may be destroyed due to irreversibility. Exergy analysis can be used to reveal the location, and amount of energy losses of engines. Despite the importance of the exergy analysis, there is a lack of information in this area, especially when the engine is fueled with biodiesel–diesel fuel blends under various injection operating parameters. Thus, in this research, the exergy analysis of a direct-injection diesel engine using biodiesel–diesel fuel blends was performed. The fuel blends (B0, B20, B40, and B100) were injected into cylinders at pressures of 200 and 215 bars. Moreover, the simulation of exergy and energy analyses was done by homemade code. The simulation model was verified by compression of experimental and simulation in-cylinder pressure data. The results showed there was good agreement between simulation data and experimental ones. Results indicated that the highest level of in-cylinder pressure at injection pressure of 215 bars is more than that of 200 bars. Moreover, by increasing the percentage of biodiesel, the heat transfer exergy, irreversibility, burnt fuel, and exergy indicator decreased, but the ratio of these exergy parameters (except for heat transfer exergy) to fuel exergy increased. These ratios increased from 46 to 50.54% for work transfer exergy, 16.57 to 17.97% for irreversibility, and decreased from 16 to 15.49% for heat transfer exergy. In addition, these ratios at 215 bars are higher than at 200 bars for all fuels. However, with increasing the injection pressure and biodiesel concentration in fuel blends, the exergy and energy efficiencies increased.

Effect of Injection Parameters and Strategy on the Noise From a Single Cylinder Direct Injection Diesel Engine

2011 ◽  
Author(s):  
Sukhbir Singh Khaira ◽  
Amandeep Singh ◽  
Marcis Jansons
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Injection Pressure ◽  
Combustion Noise ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Frequency Spectra ◽  
Single Cylinder ◽  
Direct Injection Diesel Engine ◽  
Injection Parameters

Acoustic noise emitted by a diesel engine generally exceeds that produced by its spark-ignited equivalent and may hinder the acceptance of this more efficient engine type in the passenger car market (1). This work characterizes the combustion noise from a single-cylinder direct-injection diesel engine and examines the degree to which it may be minimized by optimal choice of injection parameters. The relative contribution of motoring, combustion and resonance components to overall engine noise are determined by decomposition of in-cylinder pressure traces over a range of load, injection pressure and start of injection. The frequency spectra of microphone signals recorded external to the engine are correlated with those of in-cylinder pressure traces. Short Time Fourier Transformation (STFT) is applied to cylinder pressure traces to reveal the occurrence of motoring, combustion noise and resonance in the frequency domain over the course of the engine cycle. Loudness is found to increase with enhanced resonance, in proportion to the rate of cylinder pressure rise and under conditions of high injection pressure, load and advanced injection timing.

Preparation of Sm2Fe17 Columnar Grains Ribbons by Rapid Quenching

2014 ◽  
Vol 1004-1005 ◽  
pp. 367-370
Author(s):  
Guo Biao Lin ◽  
Xiang Luo ◽  
Wen Long Bi ◽  
Xiao Qian Bao ◽  
Wei Min Mao
Keyword(s):  
Cooling Rate ◽  
Melt Spinning ◽  
Injection Pressure ◽  
Rapid Quenching ◽  
Vacuum Melting ◽  
Nozzle Size ◽  
Columnar Grains

The ingot of Sm-Fe alloy was prepared by vacuum melting. After a process of coarse crushing, it was made into Sm-Fe ribbons by melt-spinning. By analysis of XRD and SEM, it was confirmed that the ribbons composed of fine Sm2Fe17columnar grains with almost the same orientation can be obtained under the condition of 5~7m/s surface rotating velocity of Cu wheel, suitable nozzle size, injection pressure, temperature and composition of the Sm-Fe melt to regulate cooling rate and crystallization. The achievement of the ribbons lays a foundation for preparing anisotropic Sm2Fe17Nxmagnetic powders by rapid quenching.

The Study of the Design Parameter of Lead Rubber Bearing

2012 ◽  
Vol 184-185 ◽  
pp. 591-594
Author(s):  
Jie Wang ◽  
Jian Xin Liu
Keyword(s):  
Design Parameter ◽  
Scientific Basis ◽  
Equivalent Damping ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Value Range ◽  
Isolation Device ◽  
Effective Design ◽  
Computing Method ◽  
Equivalent Linear Model

The Lead-Rubber-Bearing is a type of isolation device in entirety. Its design parameter is complicated. when it is used in bridges, it always need plenty of time to design. It is not beneficial to its application and dissemination. The design formula now available are lack of relevance，can not provide a clear and distinct computation measure. This paper explains in a systematic way the formula and reasonable value range of the design parameter. These parameters include the diameter and height of lead pin, effective design deflection, the equivalent linear model, shear strain of rubber bearing shear stress of the lead，initial rigidity and second rigidity and so on. At last this paper induces computing method of equivalent rigidity and equivalent damping constant and gives some examples。This paper gives scientific basis for the concrete design and makes the bearing standard and serial to lay a foundation for its application.

Prediction of the effect of injection parameters on NOx emission and burning quality in the direct injection diesel engine using a modified multizone model

1998 ◽  
Vol 212 (5) ◽  
pp. 427-436 ◽  
Author(s):  
H Salem ◽  
S. H. El-Bahnasy ◽  
M Elbaz
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Injection Pressure ◽  
Cylinder Pressure ◽  
Injection Parameters ◽  
Multizone Model ◽  
Engine Power

Combustion process in a quiescent chamber diesel engine is modelled using a multizone model. This model divides the cylinder charge into two zones, namely the unburnt zone (surrounding air) and the burnt zone (fuel spray with entrained air). The burnt zone is subdivided into 16 concentric sprays, instead of only eight sprays as in previous work, each one with its own temperature and composition. Liquid fuel, fuel vapour, air and products of combustion are assumed to be present in each zone. Real gas relations are used to calculate the properties of the mixture while products of combustion are assumed to be in chemical equilibrium at local temperature. The extended Zeldovich mechanism is used to predict the NO x formation. The cylinder pressure, temperature, heat release rate, NO x rate and concentration are calculated. For different injection pressures, injection advance angles and different fuel orifice hole diameters, the results show that the model can predict the measured cylinder pressure with high accuracy but it predicts the measured heat release rate and NO x emission rate with moderate accuracy. In addition, the effect of injection parameters on the NO x emission and engine power is predicted and it has been shown that NO x emission can be reduced without noticeable loss of engine power. This can be done by appropriate choice of injection pressure, injection advance angle and fuel nozzle hole diameters.

The Effect of Cooling Rate on the Formation of Dendritic Ice in a Pipe With No Main Flow

1977 ◽  
Vol 99 (3) ◽  
pp. 419-424 ◽  
Author(s):  
R. R. Gilpin
Keyword(s):  
Temperature Distribution ◽  
Cooling Rate ◽  
Dendritic Growth ◽  
Pipe Wall ◽  
Ice Nucleation ◽  
Thermal Boundary Condition ◽  
Main Flow ◽  
Freezing Process ◽  
Water Pipe ◽  
Flow Through

Dendritic ice forms in a pipe when there is no main flow through the pipe during the freezing process. This ice form occurs because the quiescent water supercools considerably below 0°C before ice nucleation occurs. It has been shown that growth of dendritic ice can cause blockage of a water pipe [1] much sooner than would have been predicted if the ice grew as a solid annulus. The extent of the dendritic growth is largely determined by the temperature distribution that exists in the pipe at the time of ice nucleation. In this paper the factors effecting the temperature distribution and thus the extent of dendritic ice growth are examined to determine the conditions under which blockage by dendritic ice is likely to occur. The factors that are important are the cooling rate the pipe is exposed to, the ice nucleation temperature, and the type of thermal boundary condition the pipe wall provides.

scholarly journals Experimental Study of Injection Parameters on the Performance of a Diesel Engine with Fischer–Tropsch Fuel Synthesized from Coal

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3280 ◽  
Author(s):  
Jinhong Shi ◽  
Tie Wang ◽  
Zhen Zhao ◽  
Tiantian Yang ◽  
Zhengwu Zhang
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Injection Pressure ◽  
Injection Timing ◽  
Nox Emissions ◽  
Cylinder Pressure ◽  
Fischer Tropsch ◽  
Ignition Point ◽  
Injection Parameters ◽  
Combustion Emissions

Experimental research was conducted on a turbo-charged, inter-cooling and common-rail diesel engine with Fischer–Tropsch fuel synthesized from Coal-to-liquid (CTL), in order to investigate the influence of different injection parameters on the combustion, emissions and efficiency characteristics of the engine. The results showed that the ignition point was advanced, the in-cylinder pressure and heat release rate increased as the injection timing advanced and the injection pressure increased. By comparing the peak in-cylinder pressure of 100 cycles for one sample, it was found that the coefficient variation (COV) remained under 2% throughout the tests and the combustion process remained stable. NOx emissions decreased with delayed injection timing and lower injection pressure. In contrast to NOXNOx emissions, soot emissions were almost zero when the injection pressure was up to 143.5 MPa. The indicated thermal efficiency (ITE) showed no obvious change with different injection parameters, and remained under 40% in all the tests.

scholarly journals Experimental Study of DI Diesel Engine Operational and Environmental Behavior Using Blends of City Diesel with Glycol Ethers and RME

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1547 ◽  
Author(s):  
Theodoros C. Zannis ◽  
Roussos G. Papagiannakis ◽  
Efthimios G. Pariotis ◽  
Marios I. Kourampas
Keyword(s):  
Diesel Engine ◽  
Oxygen Content ◽  
Direct Injection ◽  
Engine Performance ◽  
Injection Pressure ◽  
Cylinder Pressure ◽  
Performance Parameters ◽  
Glycol Ethers ◽  
Pressure Injection ◽  
Di Diesel Engine

An experimental investigation is performed in a single-cylinder direct-injection (DI) diesel engine using city diesel oil called DI1 and two blends of DI1 with a mixture of glycol ethers. The addition of glycol ethers to fuel DI1 produced oxygenated fuels GLY10 (10.2 mass-% glycol ethers) and GLY30 (31.3 mass-% glycol ethers) with 3% and 9% oxygen content, respectively. The addition of biofuel rapeseed methyl ester (RME) to fuel DI1 produced oxygenated blend RME30 (31.2 mass-% RME) with 3% oxygen content. Engine tests were performed with the four fuels in the DI diesel engine at 2500 RPM and at 20%, 40%, 60%, and 80% of full load. The experimental diesel engine was equipped with devices for recording cylinder pressure, injection pressure, and top dead center (TDC) position and also it was equipped with exhaust gas analyzers for measuring soot, NO, CO, and HC emissions. A MATLAB 2014 code was developed for analyzing recorded cylinder pressure, injection pressure, and TDC position data for all obtained engine cycles and for calculating the main engine performance parameters. The assessment of the experimental results showed that glycol ethers have more beneficial impact on soot and NO emissions compared to RME, whereas RME have less detrimental impact on engine performance parameters compared to glycol ethers.

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