scholarly journals New method for determining singularities on enveloped surface and its application to study curvature interference theory of involute worm drive

2021 ◽  
Vol 13 (8) ◽  
pp. 168781402110380
Author(s):  
Mu Shi-Bo ◽  
Zhao Ya-Ping ◽  
Wang Tian-Feng ◽  
Meng Qing-Xiang ◽  
Li Gong-Fa
Keyword(s):  
Design Parameters ◽  
Interference Theory ◽  
Numerical Result ◽  
Enveloping Surface ◽  
Study Results ◽  
Total Differential ◽  
Tangential Vector ◽  
Curvature Interference ◽  
Worm Drive ◽  
Interference Mechanism

In this paper, a more computationally convenient singularity condition of the enveloped surface is proposed using the theory of linear algebra. Its preconditions are only the tangential vector of the enveloping surface, the relative velocity vector, and the total differential of the meshing function. It avoids calculating the curvature parameters of the enveloping surface. It is proved that the singularity conditions of enveloped surface from different references are equivalent to each other and the relational equations among them are obtained. The curvature interference theory for the involute worm drive is established using the proposed singularity condition. The equation for the singularity trajectory is obtained. The calculation method for the singularity trajectory is proposed and its numerical result is obtained. The influence of the design parameters on the singularity trajectory is studied using the proposed curvature interference theory. The study results show that the risk of curvature interference is high when the transmission ratio is too small, especially in the case of the single-threaded worm and large modulus. The proposed singularity condition can also be applied to study the curvature interference mechanism in other types of the worm drive and to study the undercutting mechanism when machining the worm drive.

scholarly journals Community Design Parameters and the Performance of Residential Cogeneration Systems

2007 ◽  
Vol 4 (2) ◽  
Author(s):  
Hazem Rashed-Ali
Keyword(s):  
System Performance ◽  
Design Parameters ◽  
Base Line ◽  
Line Model ◽  
Residential Communities ◽  
Mixed Use ◽  
Study Results ◽  
Cogeneration System ◽  
Design Characteristics ◽  
The Impact

The integration of cogeneration systems in residential and mixed-use communities has the potential of reducing their energy demand and harmful emissions and can thus play asignificant role in increasing their environmental sustainability. This study investigated the impact of selected planning and architectural design parameters on the environmental and economic performances of centralized cogeneration systems integrated into residential communities in U.S.cold climates. Parameters investigated include: 1) density, 2) use mix, 3) street configuration, 4) housing typology, 5) envelope and building systems’ efficiencies, and 6) passive solar energyutilization. The study integrated several simulation tools into a procedure to assess the impact of each design parameter on the cogeneration system performance. This assessment procedure included: developing a base-line model representing typical design characteristics of U.S. residential communities; assessing the cogeneration system’s performance within this model using three performance indicators: percentage of reduction in primary energy use, percentage of reduction in CO2 emissions; and internal rate of return; assessing the impact of each parameter on the system performance through developing 46 design variations of the base-line model representing potential changes in each parameter and calculating the three indicators for each variation; and finally, using a multi-attribute decision analysis methodology to evaluate the relative impact of each parameter on the cogeneration system performance. The study results show that planning parameters had a higher impact on the cogeneration system performance than architectural ones. Also, a significant correlation was found between design characteristics identified as favorable for the cogeneration system performance and those of sustainable residential communities. These include high densities, high use mix, interconnected street networks, and mixing of housing typologies. This indicates a higher potential for integrating cogeneration systems in sustainable communities.Keywords: cogeneration; residential & mixed use communities; energy efficiency; district heating

scholarly journals Parametric Optimisation of a Trigenerative Small Scale Compressed Air Energy Storage System

Proceedings ◽  
2019 ◽  
Vol 23 (1) ◽  
pp. 5
Author(s):  
Mohamad Cheayb ◽  
Sébastien Poncet ◽  
Mylène Marin-Gallego ◽  
Mohand Tazerout
Keyword(s):  
Energy Storage ◽  
Storage System ◽  
Electric Energy ◽  
Optimal Solution ◽  
Energy Storage System ◽  
Compressed Air ◽  
Design Parameters ◽  
Small Scale ◽  
Compressed Air Energy Storage ◽  
Study Results

Recently, major improvement on compressed air energy storage technology has been made by using the heat of compression for heating energy or using it to preheat the compressed air in the expansion phase and by demonstrating its ability to produce cooling energy. Thus, the trigenerative compressed air energy storage has been introduced. In this paper, we introduce a configuration of trigenerative compressed air energy storage system giving the preference to the electric energy production. The study then focuses on undertaking an optimization study via a parametric analysis considering the mutual effects of parameters. This analysis is applied to a micro-scale application including the existing technological aspects. The parametric study results applied on the hot temperature of the thermal energy storage indicate the possibility to find an optimal solution as a trade-off between system performances and other parameters reflecting its cost. On the contrary, the selection of the maximal storage pressure cannot be achieved by finding a compromise between energy density and system efficiency. A complete study of other design parameters will be addressed in a future publication.

A Parametric Study on Interlaminar Shear Strains in Cord-Rubber Composites

1984 ◽  
Vol 57 (1) ◽  
pp. 168-183 ◽  
Author(s):  
J. DeEskinazi ◽  
R. J. Cembrola
Keyword(s):  
Shear Strain ◽  
Relative Motion ◽  
Strong Influence ◽  
Design Parameters ◽  
Cross Sectional ◽  
Design Variables ◽  
Study Results ◽  
Shear Strains ◽  
Interlaminar Shear ◽  
Belt Width

Abstract The effect of different design variables used in the construction of tire belts on the interply shear phenomenon was studied using a simple, belted cylinder structure. Only balanced belt constructions were considered. The finite element method was used in the analysis of the belted structure. Predicted results were verified by performing experiments with selected combinations of the design parameters studied. Predicted and experimental results indicate the presence of interply shear strains in the cross-sectional plane of the belts; however, due to difficulties involved in measuring these strains experimentally, they have not been treated in this study. Results for shear strains in the circumferential planes only have been presented. Results for the interply shear strains at the belt edge indicate that the belt cord angle has a very strong influence on the interply shear phenomenon. It was shown that the shape of the curve depicting the relationship between cord angle and interply shear strains is influenced by other design variables of the belt as well as properties of adjacent plies, such as the bladder used to simulate a radial tire carcass ply. Interply shear strains decrease with increasing thickness between the plies and modulus of the interply rubber. In the case of a stiffer rubber, the reduction in shear strain is entirely due to a reduction in the relative motion between the belts. However, in the case of an increased interply thickness, which is accompanied by an increase in relative motion between the belts, the reduction in shear is the result of the relative motion being distributed over a larger thickness. Increasing the belt cord modulus results in an increase in interply shear strains for relatively low values of the modulus. However, beyond a certain value, approximately the modulus of fiberglass cords, increasing the cord modulus does not significantly affect interply shear strains. The shear strain-belt width relationship is strongly influenced by the cord angle used in the belts. Depending on the value of the latter, the shear strain can be a decreasing function of belt width or remain relatively constant as belt width is varied. The degree of localization of the interply shear phenomenon at the belt edge was also studied. All of the variables considered in this study, with the exception of the cord modulus, seem to affect the distribution of the shear strain along the width of the belt to varying extents. The belt width seems to have a strong influence, with wider belts resulting in significant shear strains confined to the vicinity of the belt edge.

scholarly journals Analysis of Short-Term Prestress Losses in Post-tensioned Structures Using Smart Strands

2022 ◽  
Vol 16 (1) ◽  
Author(s):  
Sang-Hyun Kim ◽  
Sung Yong Park ◽  
Sung Tae Kim ◽  
Se-Jin Jeon
Keyword(s):  
Prestressed Concrete ◽  
General Assumption ◽  
Design Parameters ◽  
Short Term ◽  
Prestress Losses ◽  
Predictive Equations ◽  
Girder Bridges ◽  
Long Span ◽  
Prestressing Force ◽  
Study Results

AbstractThe proper estimation of prestressing force (PF) distribution is critical to ensure the safety and serviceability of prestressed concrete (PSC) structures. Although the PF distribution can be theoretically calculated based on certain predictive equations, the resulting accuracy of the theoretical PF needs to be further validated by comparison with reliable test data. Therefore, a Smart Strand with fiber optic sensors embedded in a core wire was developed and applied to a full-scale specimen and two long-span PSC girder bridges in this study. The variation in PF distribution during tensioning and anchoring was measured using the Smart Strand and was analyzed by comparison with the theoretical distribution calculated using the predictive equations for short-term prestress losses. In particular, the provisions for anchorage seating loss and elastic shortening loss were reviewed and possible improvements were proposed. A new method to estimate the amount of anchorage slip based on real PF distributions revealed that the general assumption of 3–6-mm slip falls within a reasonable range. Finally, the sensitivity of the PF distribution to a few of the variables included in the equation of the elastic shortening loss was examined. The study results confirmed that the developed Smart Strand can be used to improve the design parameters or equations in PSC structures by overcoming the drawbacks of conventional sensing technologies.

Experimental Performance Evaluation of a Catalytic Flat Plate Fuel Reformer for Fuel Cell Grade Reformate

2014 ◽  
Author(s):  
Susanta K. Das ◽  
K. Joel Berry
Keyword(s):  
Fuel Cell ◽  
Flat Plate ◽  
Reaction Rates ◽  
Design Parameters ◽  
Channel Height ◽  
Inlet Temperature ◽  
Cfd Model ◽  
Current Voltage ◽  
Study Results ◽  
Current Voltage Characteristics

Compact and efficient fuel reforming system design is a major challenge because of strict requirements of efficient heat distribution on both the reforming and combustion side. As an alternative to traditional packed bed tubular reformers, catalytic flat plate fuel reformer offers better heat integration by combining the combustion reaction on one side and reforming reaction on the other side. In this study, with the help of a two-dimensional computational fluid dynamics (CFD) model, a catalytic flat plate fuel reformer is built and investigated its performance experimentally. The CFD model simulation results help to capture the effect of design parameters such as catalyst layer thickness, reaction rates, inlet temperature and velocity, and channel height. The CFD model study results also help to design and built the actual reformer in such a way that eliminate the limitations or uncertainties of heat and mass transfer coefficients. In our study, we experimentally evaluated the catalytic flat plate fuel reformer performance using natural gas. The effect of reformate gas on the current-voltage characteristics of a 5kW high temperature PEM fuel cell (HTPEMFC) stack is investigated extensively. The results shows that the overall system performance increases in terms of current-voltage characteristics of HTPEMFC while fed with reformate directly from the catalytic flat plate reformer.

Determination of the Most Dangerous Meshing Point for Modified Hourglass Worm Drives

2011 ◽  
Author(s):  
Yaping Zhao ◽  
Tianchao Wu
Keyword(s):  
Nonlinear Equations ◽  
Slight Modification ◽  
Second Step ◽  
System Of Nonlinear Equations ◽  
Type Ii ◽  
Severe Condition ◽  
Worm Gearing ◽  
Curvature Interference ◽  
Worm Drive

A kind of modified hourglass worm drives, which is frequently called the type II worm gearing for short, has various favorable meshing features. Nevertheless, its sole shortcoming is the undercutting of the worm wheel. In the condition of adopting slight modification, this problem can be overcome due to the removal of a part of one sub-conjugate area containing the curvature interference limit line. In order to measure the effect of the avoidance of undercutting, a strategy to determine the meshing point in the most severe condition is proposed for a type II worm drive. The presented strategy can be divided into two steps. The first step is to establish a system of nonlinear equations in five variables in accordance with the theory of gearing. The second step is to solve the procured nonlinear equations by numerical iterative method to ascertain the meshing point required. A numerical example is presented to verify the validity and feasibility of the proposed scheme.

scholarly journals The Analysis of the Influence of Rock Massif Water Saturation on the Mine Workings Anchoring Design Parameters

2019 ◽  
Vol 105 ◽  
pp. 01027
Author(s):  
Sergey Tsibaev ◽  
Alexey Renev ◽  
Evgenyi Kudrin ◽  
Damir Zaiatdinov
Keyword(s):  
Compression Strength ◽  
Water Saturation ◽  
Sedimentary Rocks ◽  
Strength Properties ◽  
Design Parameters ◽  
Uniaxial Compression Strength ◽  
Petrographic Composition ◽  
Study Results ◽  
Mine Workings ◽  
Water Saturated

Here in the study results of the sedimentary rocks water saturation effect on the main parameters of anchoring of mine workings: resistance, density and installation step of the support. A series of tests of rock samples with different intervals of their water saturation has been produced. It has been established that water saturation leads to a significant change in the strength properties of sedimentary rocks, depending on their petrographic composition and the period of exposure to moisture. The relation between the degree of water saturation and a decrease in the uniaxial compression strength, between the strength of a dry sample and its tendency to decrease in strength properties under the influence of moisture, between the period of exposure to moisture and decrease in strength properties has been established. The results of the study will allow to more accurately classify the rocks of the roof according to the factors of collapse and stability, which has a significant impact on the calculation of the anchoring parameters of mine workings in water-saturated zones.

scholarly journals Theoretical Study for an Adsorption Refrigerator

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Abdulghani M. Ramadan
Keyword(s):  
Adsorption Capacity ◽  
Waste Heat ◽  
Cooling System ◽  
Operating Conditions ◽  
Equilibrium Adsorption ◽  
Design Parameters ◽  
Low Grade ◽  
Equilibrium Pressure ◽  
Study Results ◽  
Equilibrium Adsorption Capacity

Adsorption cooling technology is one of the effective means to convert low grade thermal energy in to effective cooling, which improves energy efficiency and lowers environmental pollution. The main objective of this study is to investigate the thermal performance of an adsorption refrigerator theoretically. The working adsorbent/adsorbate pair used is Granular Activated Carbon, GAC/R134a pa*ir. The effect of different design parameters and operating conditions on the system performance is studied and interpreted.Some assumptions and approximations are also considered. A computer program is written using Matlab. Results show that the equilibrium adsorption capacity is highly affected by the driving temperature and equilibrium pressure. Increasing equilibrium pressure leads to a corresponding increase in the equilibrium adsorption capacity whereas it is value is decreased as the driving temperature increases. Moreover, increasing the driving and evaporator temperatures raise the values of the Specific Cooling Effect (SCE) andCoefficient of Performance (COP). The maximum values of SCE and COP are 60 KJ/kg and 0.4 corresponding to driving and evaporator temperatures of 100 oC and 20 oC respectively. However, increasing the condenser temperature leads to a remarked decrease in SCE and COP of the cooling system. SCE and COP values are 32 KJ/kg and 0.22 at driving and condenser temperatures of 100 oC and 40 oC respectively. When comparing the present study results with literature, there is a good agreement in general. It is clear that the adsorption cooling system can be driven effectively by low grade heat sources such as, solar energy, waste heat energy, geothermal energy…etc.

Resonance Reliability Sensitivity Analysis for Random Cam Mechanism System

2013 ◽  
Vol 842 ◽  
pp. 378-381
Author(s):  
Xin Xin Si ◽  
Rui Jun Zhang ◽  
Lu Lu Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Perturbation Method ◽  
Stability Criterion ◽  
Random Variables ◽  
Design Parameters ◽  
Performance Function ◽  
Cam Mechanism ◽  
Reliability Sensitivity ◽  
Reliability Sensitivity Analysis ◽  
Study Results

Targeting at realizing analysis of resonance reliability sensitivity for cam mechanism system, considering the uncertainty of the design parameters, the performance function of the resonance reliability of the cam mechanism is established based on stability criterion of vibration. The perturbation method is employed to calculate the resonance reliability of cam mechanism. Combined with the sensitivity technology, the effects of random variables on occurring resonance failure of cam mechanism system were discussed. The study results can provide theoretical reference for anti-resonance design of cam mechanism system.

Determination of the Most Dangerous Meshing Point for Modified-Hourglass Worm Drives

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Yaping Zhao ◽  
Yimin Zhang
Keyword(s):  
Nonlinear Equations ◽  
Slight Modification ◽  
System Of Nonlinear Equations ◽  
Type Ii ◽  
Severe Condition ◽  
Numerical Iteration ◽  
Worm Gearing ◽  
Curvature Interference ◽  
Worm Drive

A type of modified-hourglass worm gear drive, frequently called type-II worm gearing for short, has various favorable meshing features. Its sole shortcoming is the undercutting of the worm wheel. By adopting a slight modification, this problem can be overcome due to the removal of a part of one subconjugate area containing the curvature interference limit line. To measure how effectively the undercutting is avoided, a strategy to determine the meshing point in the most severe condition is proposed for a type-II worm drive. The strategy presented consists of two steps. The first step is to establish a system of nonlinear equations in five variables in accordance with the theory of gearing. The second step is to solve the system of nonlinear equations by a numerical iteration method to ascertain the meshing point required. A numerical example is presented to verify the validity and feasibility of the proposed scheme.

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