Consume Power Torque and Conveyor energy efficiency for a Horizontal Screw Conveyor with three different Screw Flight –A Comparison

Material handling cost plays crucial role in any manufacturing industries. A judicious selection of material handling system or equipment can only help to enhance productivity and thereby increasing profitability of an industry. Extensive studies require for establishing cost effective solution related to selection of right handling system. The objective of work is to find out running cost associated with screw type horizontal conveyor through experimental investigation of consume power and associated torque against three different types of screw flight(Continuous, Ribbon and Cut Flight) of same nominal diameter and pitch while keeping conveying distance as constant with same material at different screw speed. The experiment was conducted against two different trough heights for finding out mass flow rate. The consume power, torque and conveying energy efficiency calculated with three different screw flight and the results were compared for analysis. Hence on the basis of experimental results, conclusion was drawn. Present work confirming experimentally that the consume power at conveyor shaft and torque in case of ribbon flight was found to be 10 percent less than that of the continuous screw type of same nominal diameter, pitch and helix angle with same range of speed against single conveying material type in case of both the trough height(112 mm and 180 mm), which was in line with the statement made earlier[6]. In addition to that a trial has been made to establish a comparison in terms of consume power in between ribbon and cut flight against a constant trough height, which was not reported earlier. This comparative study may be helpful for taking decision in selecting material handling equipment type for specific application area. Now a day overall energy consumption becomes serious concern for different industries.

Proposal on Hybrid Design Method of Outer Port Facilities Using Failure Probability

Lately, many efforts have been made to address the problem concerned with deterministic design using reliability-based design, and the research results are significant. However, there is considerable confusion in the design practice regarding how to use failure probability, the main output of reliability-based design. In this rationale, this study aims to develop a robust hybrid deterministic design method for outer port facilities using the failure probability. To this end, we first reviewed the design process of Eulleungdo East Breakwater, some of which were recently damaged. It was revealed that the exceeding probability of design wave height of 5.2 m was merely 0.65, which corresponds to a return period of 1.53 years, showing that the outer port facilities of Ulleungdo were considerably underdesigned. In an effort to find an alternative that can overcome the limitations of the deterministic design method, which is highly likely to involve subjective judgment, a Level III reliability design was carried out. In doing so, tri-modal Gaussian wave slope distribution was used as a probabilistic model for wave slope. Numerical results show that failure probability was excessively estimated in the Gaussian distribution, and even if the TTP size was slightly reduced, the failure probability increased rapidly. Although failure probability is sensitive to the change in nominal diameter, there is a gradually increasing zone where the failure probability change rapidly decreases when the nominal diameter is larger than the critical value. The presence of a Gradually Increasing Zone mentioned above implies that it is uneconomical and has no physical background to adjust the nominal diameter to be larger than the critical value. Therefore, it can be easily conceived that outer port facility design should be performed using a failure probability provided by Level III reliability-based design.

Systematic Comparison on Convective Heat Transfer Characteristics of Several Pin Fins for Turbine Cooling

This paper is focused on the heat transfer augment ability and friction factor of different cross-section pin fins. An experimental study is conducted in a wide rectangular channel. The steady-state thermochromic liquid crystals (TLC) method is applied to measure the tested surface temperature. Nine sets of pin fins are employed in the experiment. The nominal diameter of all pin fins is the same value. Nine sets of pin fins have three roundness shapes (Circle, Ellipse and Oblong), three streamline shapes (Dropform, NACA and Lancet) and three quadrangle shapes (Diamond, Diamond-s and Square), respectively. The arrangement parameters of all nine shapes are kept the same. As they have the same nominal diameter and arrangement, the channel blockage ratio is the same for each pin fin set. Reynolds numbers range from 10,000 to 60,000. The pressure losses of pin fin arrays are measured to obtain friction factor. Meanwhile, the overall thermal performances of all nine sets are also considered and compared. The results show heat transfer enhancement abilities of quadrangle shape pin fins are relatively higher than the roundness and streamline shapes. Diamond-s pin fins present the largest averaged Nusselt number and overall thermal performance on the endwall for all the nine pin fins under different Re. Concerning overall thermal performance, the traditional Circle pin fin is the second best. The pressure loss of streamline shape pin fins is the lowest in these three shape types. Moreover, the characteristic of local heat transfer distribution varies substantially for different pin shapes at low Re.

Analysis of Flow Characteristics and Effects of Turbulence Models for the Butterfly Valve

In the present study, the flow characteristics of butterfly valves with different sizes DN 80 (nominal diameter: 76.2 mm), DN 262 (nominal diameter: 254 mm), DN 400 (nominal diameter: 406 mm) were numerically investigated under different valve opening percentages. Representative two-equation turbulence models of two-equation k-epsilon model of Launder and Sharma, two-equation k-omega model of Wilcox, and two-equation k-omega SST model of Menter were selected. Flow characteristics of butterfly valves were examined to determine turbulence model effects. It was determined that increasing turbulence effect could cause many discrepancies between turbulence models, especially in areas with large pressure drop and velocity increase. In addition, sensitivity analysis of flow properties was conducted to determine the effect of constants used in each turbulence model. It was observed that the most sensitive flow properties were turbulence dissipation rate (Epsilon) for the k-epsilon turbulence model and turbulence specific dissipation rate (Omega) for the k-omega turbulence model.

Detektion von Schneidkantenversatz und Rautiefe/Surface quality and cutting edge offset detection

Bei Drehbearbeitung auftretender Verschleiß am Werkzeug ist seit Jahrzehnten Gegenstand der Forschung, denn er beeinflusst die Oberflächengüte und den resultierenden Durchmesser des Werkstücks. Durch die gezielte Platzierung eines Triangulationssensors lassen sich Einflüsse dieser Art detektieren. In Zerspanungsuntersuchungen bei der Bearbeitung des austenitischen Stahls 1.4301 ohne Kühlmedium konnte gezeigt werden, dass der verschleißbedingte Durchmesserfehler und die hergestellte Oberflächentopografie prozesssicher messbar sind.   Tool wear and its detection has been part of academic research for decades. It may result in varying surface quality and is a potential cause of insufficient nominal diameter in turning. Mounting a triangulation laser on a turning tool allows for detecting variations in geometrical parameters of the workpiece. Also, when dry turning the austenitic steel 1.4301 it is possible to continuously detect the resulting surface topography and the discrepancy in the manufactured diameter.

Development of an in vitro measurement method for improved assessment of the side branch expansion capacity

The expansion capacity and accessibility of the side branch is essential for the stenting of complex bifurcations. Since previous measurement methods only provide limited information based on geometrical data of stent cells, a new measurement approach was developed which considers the mechanical deformation capacity of the stent design. This approach provides essential information on the stent with regard to the application of bifurcation stenting. Four different commercially available coronary stents (nominal diameter 3.0 mm) were dilated and a central strut cell was over-expanded by means balloon catheters of increasing nominal diameter (2.0 to 5.0 mm). After balloon inflation, the remaining cell size was investigated for maximum cell diameter and strut fractures. Large expansion capacity without cell damage is taken as a measure of the accessibility of the side branch. In none of the expansion experiments the desired target size could be achieved, which is due to the elastic recoil of the stent cells. Deviations from the target diameter between 14-38% were determined. However, larger diameters also showed a constriction of the balloon, so that in some cases the target diameter could not be achieved at all. No strut fractures occurred even at maximum balloon diameter and pressure (5.0 mm noncompliant balloons). As a result the side branch accessibility differs depending on the individual stent designs. No particular risk for the stent was found by extensive overdilatation.

A Calculation Method of the Load Factor and Design for Bolted Gasketed Pipe Flange Connections Under Internal Pressure

The contact gasket stress reduces when the bolted gasketed pipe flange connections are subjected to internal pressure. In designing the bolted connections, it is needed to predict the reduced contact gasket stress, so, it is necessary to know the load factor. However, it is difficult to estimate the value of the load factor of the connections under internal pressure. In the previous paper (2018PVP), a more simpler calculation method was proposed. However, a more accuracy for obtaining the values of the load factor is desirable using the spring constants Ktg and Kcg. In the present paper, some calculation models for the spring constants are improved. Then, the values of the load factor for JIS 10K flange connections and ASME B16 flange connections with spiral wound gaskets are shown. The values of the load factor for the above connections are in a fairy good agreement with the FEM results. Using the obtained load factor, the residual contact gasket stress and an amount of gas leakage are predicted. The obtained calculated results of the load factor and the amount of the leakage are in a fairly good agreement with FEM results, and the measured results for 24” connection. As a result, the value of the load factor for the connections with larger nominal diameter is found to be negative and it decreases as the nominal flange diameter increases. In addition, a method how to determine the bolt preload for satisfying a give allowable leak rate is demonstrated.

Sustained Pressure Test Results for Surface Scratches in PE4710, Cell Classification 445574C High Density Polyethylene Pipe Material

Mandatory Appendix XXVI of the ASME Boiler and Pressure Vessel Code (BPVC), Section III, Division 1 currently permits the use of high-density polyethylene (HDPE) in buried safety Class 3 piping systems. There have been concerns about how the slow crack growth (SCG) of HDPE emanating from surface scratches that may occur during fabrication or installation. The current allowable scratch depth in Appendix XXVI is 5% of the pipe wall thickness for pipe 4 inch and less in nominal diameter pipe and 0.040 inch (1mm) for pipe greater than 4 inch nominal diameter. This report presents the results of further investigation into the SCG rates by testing of notched PE 4710 HDPE pipes made from PE 4710 cell classification 445574C bimodal resins that meet the requirements of Appendix XXVI. These tests were conducted by first making razor-cut surface scratches in 4 inch, 8 inch, and 16 inch nominal diameter piping made by three different piping manufacturers using three different resins. The pipes were end-capped and pressure-tested at elevated temperature until failure, or until a prescribed number of test hours were reached. The razor cuts were at different depths and lengths so as to result in a variety of stress intensities, net section stresses, and nominal stresses. Following failure, or after the prescribed number of test hours was reached, the pipe specimens were inspected to determine the amount of SCG. This paper presents the results of the testing and recommended ASME BPVC Appendix XXVI changes for allowable crack depth based on the testing are provided.

Bond Stresses between Reinforcing Bar and Reactive Powder Concrete

A good performance of reinforced concrete structures is ensured by the bond between steel and concrete, which makes the materials work together, forming a part of solidarity. The behavior of the bond between the reinforcing bar and the surrounding concrete is significant to evaluate the cracking control in serviceability limit state and load capacity in the ultimate limit state. In this investigation, the bond stresses between reinforcing bar and reactive powder concrete (RPC) was considered to compare it with that of normal strength concrete (NSC). The push-out test with short embedment length is considered in this study to evaluate the bond strength, bond stress-slip relationship, and bond stress-crack width relationship for reactive powder concrete members. The compressive strength of concrete, the nominal diameter of reinforcement, concrete cover, and amount of steel fibers and embedded length of reinforcement were considered as variables in this study. The test results show that the ultimate bond stress increased with increasing of the compressive strength of concrete, decreasing the nominal diameter of the reinforcing bar, increasing the concrete cover and increasing steel fiber content. In a bond stress-slip relationship, the NSC specimen shows a very short softening zone after reaching the peak point in comparisons with RPC specimen. In RPC, bond stress-slip relationship shows stiffer behavior when the steel fiber content was increased. RPC shows stepper softening zone due to the presence of steel fiber, and the absence of steel fiber cause push-out failure without descending part after peak point. Using NSC instead of RPC in anchorage between reinforcement and concrete, decrease the crack width produced due to radial tensile stresses through the push-out of reinforcing bar. In RPC, the absence of steel fiber, decrease the nominal diameter of the reinforcing bar, increase the concrete cover, decrease the embedded length of reinforcing bar cause push-out failure and vice versa cause splitting failure.

FEM Stress Analysis and Mechanical Characteristics of Bolted Pipe Connections With Larger Nominal Diameter Inserting PTFE Blended Gasket Under Internal Pressure

The sealing performance prediction of bolted pipe flange connections with gaskets is important factor. However, it is known that the sealing performance of the larger nominal diameter connection is worse than that with smaller nominal diameter connection due to the flange rotation. Furthermore, recently PTFE blended gaskets were developed newly and the excellent sealing performance in the bolted pipe flange connection with smaller nominal diameter is found. So, it is necessary to examine the sealing performance and the mechanical characteristics of pipe flange connections with larger nominal diameter under internal pressure. The objectives of present study are to examine the mechanical characteristics of the pipe flange connection with PTFE blended gasket under internal pressure such as the load factor, the contact gasket stress distribution and the sealing performance using FEM and experiments. Using the obtained contact gasket stress distribution and the fundamental leak rate for smaller PTFE gasket, the leak rate of the connection is predicted under internal pressure. In the FEM calculation, the effects of the nominal diameter of pip flange connections on the mechanical characteristics are shown. In the experiments, ASME class 300 24” pipe flange connections is used and the gasket is chosen as No.GF300 in PTFE blended gaskets. The FEM results of the axial bolt forces are in a fairly good agreement with the experimental results. In addition, the leak rate obtained from the FEM calculations are fairly coincided with the measured results. The mechanical characteristics of pipe flange connection with PTFE blended gasket are compared with those with spiral wound gasket.