Temperature rise characteristics of the valve-controlled adjustable damping shock absorber

2020 ◽  
Vol 21 (1) ◽  
pp. 111
Author(s):  
Fangwei Xie ◽  
Jinxin Cao ◽  
Erming Ding ◽  
Kuaidi Wan ◽  
Xinshi Yu ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Heat Dissipation ◽  
Shock Absorber ◽  
Heat Radiation ◽  
Vibration Velocity ◽  
Outer Diameter ◽  
Dissipation Model ◽  
The Difference

The thermodynamic study of the valve-controlled adjustable damping shock absorber is conducted in order to solve the problem of oil leakage caused by excessive temperature rise of shock absorber. In this paper, the temperature rise of the valve-controlled adjustable damping shock absorber is analyzed from the perspective of energy conservation. Combined with the theory of fluid mechanics, the damping heat model is established, and the heat dissipation model of the shock absorber is established based on heat convection, heat conduction and heat radiation. The corresponding thermal equilibrium equation is established on the basis of damping heat and heat dissipation. The effects of vibration velocity, outer diameter, thickness and length of reservoir cylinder, and wind velocity on its thermal performance have been investigated. Specifically, temperature after thermal equilibrium will grow with the increase of vibration velocity and thickness of reservoir cylinder and degrade with the increase of outer diameter, length of reservoir cylinder and wind velocity. The higher the balance temperature, the shorter time is required to arrive thermal equilibrium. The difference between the experimental and simulation values of oil temperature after thermal equilibrium was not more than 2 °C, which verified the correctness of the theoretical model, while the experimental value in the process of temperature rise lagged behind the simulation value, which was mainly caused by the cumulative error of step-by-step iteration and the mechanical hysteresis in the experiment. The conclusions obtained can provide some references for the design of shock absorbers.

scholarly journals A new method to calculate the friction coefficient of ball screws based on the thermal equilibrium

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882073
Author(s):  
Lu-Chao Zhang ◽  
Li Zu
Keyword(s):  
Friction Coefficient ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Heat Dissipation ◽  
Mechanical Efficiency ◽  
New Method ◽  
Measuring System ◽  
Ball Screw ◽  
Heat Absorption ◽  
Screw Mechanism

Based on the theory of thermal transmission, this article provides a new method to acquire the friction coefficient in ball screw mechanism. While the screw is in thermal equilibrium, the heat absorption is equal to the heat dissipation. The heat absorption is able to be achieved by calculating the heat energy due to the friction at the contact area and the heat dissipation can be calculated by the law of thermodynamics. When the temperature rise is determined, the heat dissipation can be obtained and the friction coefficient in ball screw mechanism can be calculated further. In order to confirm the validity of this method, a measuring system is constructed to obtain the temperature rise of ball screws. The experimental results show that the temperature rise has the same tendency with the theoretical values depending on this model. Therefore, it can be exploited to predict the temperature rise of ball screws in the rated life cycle when the ball screw is under the condition of thermal equilibrium. Furthermore, this model can be used to evaluate the mechanical efficiency, which is an important parameter for the performance of the ball screw.

scholarly journals Simulation of heat dissipation model of lithium-ion battery pack

2021 ◽  
Vol 300 ◽  
pp. 01014
Author(s):  
Maode Li ◽  
Chuan He ◽  
Jinkui Zheng
Keyword(s):  
Phase Change ◽  
Temperature Rise ◽  
Heat Dissipation ◽  
Lithium Ion ◽  
Maximum Temperature ◽  
Air Cooling ◽  
Power Battery ◽  
Staggered Arrangement ◽  
Dissipation Model ◽  
Cooling Methods

Lithium-ion power battery has become an important part of power battery. According to the performance and characteristics of lithiumion power battery, the influence of current common charge and discharge and different cooling methods on battery performance was analysed in this paper. According to the software simulation, in the 5C charge-discharge cycle, the maximum temperature of the cells with regular arrangement is 57.97°C, the maximum temperature of the cells with staggered arrangement is 55.83°C, and the maximum temperature of phase change cooling is 47.42°C. The most important thing is that the temperature difference between the cells with phase change cooling is only 5.5°C. Some simulation results of air cooling and phase change show that phase change cooling can control the heat dissipation and temperature rise of power battery well. The research in this paper can provide better theoretical guidance for the temperature rise, heat transfer and thermal management of automotive power battery.

Temperature Rise Times in Pneumatic Tires

1976 ◽  
Vol 4 (3) ◽  
pp. 181-189 ◽  
Author(s):  
S. K. Clark
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Transfer Coefficients ◽  
Pneumatic Tire ◽  
Heat Transfer Coefficients ◽  
Idealized Model ◽  
Pneumatic Tires

Abstract An idealized model is proposed for heating of a pneumatic tire. A solution is obtained for the temperature rise of such a model. Using known thermal properties of rubber and known heat transfer coefficients, the time to reach thermal equilibrium is estimated.

Effect Analysis of Nitrogen Injection on the Variation of “Oxidation Zone” in Coal Mine Gob Based on Numerical Simulation

2016 ◽  
Vol 9 (1) ◽  
pp. 47-54
Author(s):  
Jing Shen ◽  
Mingran Chang
Keyword(s):  
Numerical Simulation ◽  
Coal Mine ◽  
Heat Dissipation ◽  
Spontaneous Combustion ◽  
Oxidation Zone ◽  
Effect Analysis ◽  
Mine Fire ◽  
Nitrogen Injection ◽  
The Difference ◽  
Residual Coal

One of the main reasons for coal mine fire is spontaneous combustion of residual coal in gob. As the difference of compaction degree of coal and rock, the underground gob can be considered as a porous medium and divided into “three zones” in accordance with the criteria. The “three zones” are “heat dissipation zone”, “oxidation zone” and “choking zone”, respectively. Temperature programming experiments are taken and numerical simulation with obtained experimental data is utilized to analyze the distribution of “three zones” in this paper. Different width and depth of “oxidation zone” are obtained when the inlet air velocity is changed. As the nitrogen injection has inhibition effect on spontaneous combustion of residual coal in gob, nitrogen is injected into the gob. The widths of “oxidation zone” are compared before and after nitrogen injection. And ultimately the optimum location and volume of nitrogen injection are found out.

scholarly journals Research computer numerical simulation on heat dissipation model of submarine data centre based on TOPSIS model

2021 ◽  
Vol 2083 (4) ◽  
pp. 042062
Author(s):  
Rui Qin ◽  
Man Zhang ◽  
Lijie Chen ◽  
Xiao Liu ◽  
Zhengtao Lei ◽  
...  
Keyword(s):  
Data Centers ◽  
Heat Dissipation ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Model Material ◽  
Physical Parameters ◽  
Deep Seawater ◽  
Dissipation Model ◽  
Computer Numerical Simulation ◽  
Optimal Evaluation

Abstract Due to the huge energy consumption of land-based data centers, it is necessary to establish undersea data centers as soon as possible in order to alleviate the problem of resource tension. In this paper, the uniformity of containers is assumed. Through force analysis, it is found that the stress of containers is uniformly distributed, so only the external stress should be considered. Hypothesis submarine data center in the 50 m deep seawater, calculate the container need to withstand stress is 76.417403 Mpa, common material in engineering field, then physical parameters of material to deal with the dimensional and normalization, and establishes a comprehensive evaluation model material, the Topsis method is adopted to solve, to solve the optimal evaluation of the results can be divided into: 7-4 PH Stainless Stee 0.7450 points, so choose it as IU server container material.

COMPARATIVE ANALYSIS OF THE RESULTS OF MODELING THE DEPRECIATION OF SMALL ARMS WHEN FIRED IN QUASI-STATIC AND DYNAMIC PRODUCTIONS

2020 ◽  
Vol 6 ◽  
pp. 24-28
Author(s):  
V.L. BARANOV ◽  
A.S. LEVIN
Keyword(s):  
Comparative Analysis ◽  
Elastic Element ◽  
Shock Absorber ◽  
Initial Conditions ◽  
Small Arms ◽  
Dynamic Formulation ◽  
The Difference

Various variants of the initial conditions for calculating the dynamics of the elastic element of the shock absorber are considered. A comparative analysis of the influence of initial conditions on the difference in calculations in the quasi-static and dynamic formulation is carried out.

Introduction to light absorption: visible and ultraviolet spectra

2000 ◽  
Author(s):  
Robert K. Poole ◽  
Uldis Kalnenieks
Keyword(s):  
Electromagnetic Radiation ◽  
Light Absorption ◽  
Energy State ◽  
Monochromatic Light ◽  
Heat Radiation ◽  
Infrared Light ◽  
Visible Radiation ◽  
Absorption Of Light ◽  
The Difference

Light is a form of electromagnetic radiation, usually a mixture of waves having different wavelengths. The wavelength of light, expressed by the symbol λ, is defined as the distance between two crests (or troughs) of a wave, measured in the direction of its progression. The unit used is the nanometre (nm, 10-9 m). Light that the human eye can sense is called visible light. Each colour that we perceive corresponds to a certain wavelength band in the 400-700 nm region. Spectrophotometry in its biochemical applications is generally concerned with the ultraviolet (UV, 185-400 nm), visible (400-700 nm) and infrared (700-15 000 nm) regions of the electromagnetic radiation spectrum, the former two being most common in laboratory practice. The wavelength of light is inversely related to its energy (E), according to the equation: . . . E = ch/ λ . . . where c denotes the speed of light, and h is Planck’s constant. UV radiation, therefore, has greater energy than the visible, and visible radiation has greater energy than the infrared. Light of certain wavelengths can be selectively absorbed by a substance according to its molecular structure. Absorption of light energy occurs when the incident photon carries energy equal to the difference in energy between two allowed states of the valency electrons, the photon promoting the transition of an electron from the lower to the higher energy state. Thus biochemical spectrophotometry may be referred to as electronic absorption spectroscopy. The excited electrons afterwards lose energy by the process of heat radiation, and return to the initial ground state. An absorption spectrum is obtained by successively changing the wavelength of monochromatic light falling on the substance, and recording the change of light absorption. Spectra are presented by plotting the wavelengths (generally nm or μm) on the abscissa and the degree of absorption (transmittance or absorbance) on the ordinate. For more information on the theory of light absorption, see Brown (1) and Chapters 2, 3 and 4. The most widespread use of UV and visible spectroscopy in biochemistry is in the quantitative determination of absorbing species (chromophores), known as spectrophotometry.

Analysis of Stress Distribution for Powder Compression Molding by Finite Element Method

2019 ◽  
Vol 891 ◽  
pp. 269-274 ◽  
Author(s):  
Prakorb Chartpuk ◽  
Chaiwat Chaimahapuk
Keyword(s):  
Stress Distribution ◽  
Natural Frequency ◽  
Ceramic Powder ◽  
Bearing Steel ◽  
Outer Diameter ◽  
Maximum Compression ◽  
Aisi 52100 ◽  
Steel Aisi ◽  
The Difference ◽  
Powder Compression

The ultrasonic mold was designed for the ceramic powder compression. CAD and CAE were used in the design to analyze the mold strength and its natural frequency. The study of stress distribution and compression in upper and lower punch, mold body and waveguide comparison of stresses was analyzed by FEA experiments under maximum compression at 50,000 N to validate the results of both methods and the mold natural frequency. The difference between FEA and experimental analysis was 3-7%, acceptable. The redesign results in a cylindrical mold body with the outer diameter of 80 mm, the height of 100 mm, and the upper punch of 125 mm in length. The six sides are 26 mm of the high waveguide with 100 mm height. The internal and external diameters are 80 and 110 mm, respectively. The mold has been redesigned and can support the maximum compression force of 1,500 kN. with the bearing steel, AISI 52100, obtainable hardness 65 HRC, the stress concentration occurs at the neck of the upper punch using the ultrasonic at 12.00 to 12.45 kHz.

Effect of heating rate on evaporative heat loss in the microwave-exposed mouse

1982 ◽  
Vol 53 (2) ◽  
pp. 316-323 ◽  
Author(s):  
C. J. Gordon
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Heat Dissipation ◽  
Dew Point ◽  
Whole Body ◽  
Evaporative Heat Loss ◽  
Heat Absorption ◽  
Deep Body Temperature ◽  
The Difference ◽  
Body Heat

Male CBA/J mice were administered heat loads of 0–28 J X g-1 at specific absorption rates (SARs) of either 47 or 93 W X kg-1 by exposure to 2,450-MHz microwave radiation at an ambient temperature of 30 degrees C while evaporative heat loss (EHL) was continuously monitored with dew-point hygrometry. At an SAR of 47 W X kg-1 a threshold heat load of 10.5 J X g-1 had to be exceeded before EHL increased. An approximate doubling of SAR to 93 W X kg-1 reduced the threshold to 5.2 J X g-1. Above threshold the slopes of the regression lines were 1.15 and 0.929 for the low- and high-SAR groups, respectively. Thus the difference in threshold and not slope attributes to the significant increase in EHL when mice are exposed at a high SAR (P less than 0.02). In separate experiments a SAR of 47 W X kg-1 raised the deep body temperature of anesthetized mice at a rate of 0.026 degrees C X s-1, whereas 93 W X kg-1 raised temperature at 0.049 degrees C X s-1. Hence the sensitivity of the EHL mode of heat dissipation is directly proportional to the rate of heat absorption and to the rate of rise in body temperature. These data contradict the notion that mammals have control over whole-body heat exchange only (i.e., thermoregulation) but instead indicate that the EHL system is highly responsive to the rate of heat absorption (i.e., temperature regulation).

scholarly journals In Bangladeshi Female Cadaver, the Change of Outer Diameter of the Infundibulum of Fallopian Tube in Advancing Age

2018 ◽  
Vol 8 (2) ◽  
pp. 23-25
Author(s):  
Hasna Hena ◽  
Shamim Ara ◽  
Hosna Ara Perven ◽  
Dilruba Siddiqua ◽  
Fatema Johora ◽  
...  
Keyword(s):  
Fallopian Tube ◽  
Age Groups ◽  
Normal Structure ◽  
Outer Diameter ◽  
Fallopian Tubes ◽  
Cross Sectional ◽  
Medical College ◽  
The Difference ◽  
Group B ◽  
The Right

Context: Problems with the fallopian tubes can lead to infertility. Disease can be defined and measured only in terms of deviation from normal structure. Detailed morphological and histological knowledge is essential for the diagnosis and management of fallopian tube disease. Objectives: To identify the outer diameter of the infundibulum and its changes with advancing age. Study Design: Cross sectional descriptive type of study. Period and place: Department of anatomy, Dhaka Medical College from July 2008 to June 2009. Materials: Present study was performed on post mortem fallopian tubes of 60 Bangladeshi female. Among them lowest age was 12 years and highest age was 50 years. Methods: Samples were divided into three differential age groups: Group A (10-13 years), Group B (14-45 years), Group C (46-50 years). All samples were studied morphologically and histologically. Results: The mean outer diameter of the infundibulum of the right and left fallopian tubes ranged from 0.80±0.01 to 1.03±0.22 mm. The difference between all the groups were statistically significant (p < 0.001). Conclusion: There was change in outer diameter of the infundibulum of fallopian tubes of left and right in relation to age. Update Dent. Coll. j: 2018; 8 (2): 23-25

Sign in / Sign up

Export Citation Format

Share Document