Investigation on the Effect of Impeller Design Parameters on Performance of a Low Specific Speed Centrifugal Pump Using Taguchi Optimization Method

In order to investigate the effect of blade design on pump performance, a CFD analysis was carried out, and the results were compared with experimental performance data of a low specific speed radial pump, which presents a good agreement. After model verification, the effect of impeller geometrical parameters includes blade outlet angle, wrap angle, and width at the exit, was investigated on the pump’s performance. Moreover, these parameters were chosen on three levels using an L9 orthogonal standard array of the Taguchi optimization method. The efficient levels of variables were calculated using the analysis of variance (ANOVA) method. The results revealed that impeller width at exit and blade outlet angle is the most effective pump shaft power and efficiency parameters. To minimize power, the optimal levels are the outlet angle of 27∘∘, wrap angle of 150∘∘, and width at the exit of 9 mm. Further, an outlet angle of 23∘∘, a wrap angle of 155∘∘, and a width at the exit of 9 mm lead to maximum pump efficiency. According to the validation simulations, an increase of 2.4% inefficiency and a minimum power of 3.9KW were achieved. The Overall Evaluation Criteria (OEC) technique revealed that considering 23∘∘, 160∘∘, and 9 mm for outlet angle, wrap angle, and width at the exit, minimum shaft power, and maximum pump efficiency will be achieved. ANOVA introduced width at the exit as the most governing parameter of pump performance characteristics.

Experimental and Numerical Analysis of the Impeller Backside Cavity in a Centrifugal Compressor for CAES

Relying on a closed test rig of a high-power intercooling centrifugal compressor for compressed air energy storage (CAES), this study measured the static pressure and static temperature at different radii on the static wall of the impeller backside cavity (IBC) under variable rotating speeds. Simultaneously, the coupled computations of all mainstream domains with IBC or not were used for comparative analysis of the aerodynamic performances of the compressor and the internal flow field in IBC. The results show that IBC has a significant impact on coupling characteristics including pressure ratio, efficiency, torque, shaft power, and axial thrust of the centrifugal compressor. The gradients of radial static pressure and static temperature in IBC both increase with the decrease of mainstream flow or the increase of rotating speed, whose distributions are different under variable rotating speeds due to the change of the aerodynamic parameters of mainstream.

Estimation and Mitigation of Unknown Airplane Installation Effects on GPA Diagnostics

In gas turbines used for airplane propulsion, the number of sensors are kept at a minimum for accurate control and safe operation. Additionally, when data are communicated between the airplane main computer and the various subsystems, different systems may have different constraints and requirements regarding what data transmit. Early in the design process, these parameters are relatively easy to change, compared to a mature product. If the gas turbine diagnostic system is not considered early in the design process, it may lead to diagnostic functions having to operate with reduced amount of data. In this paper, a scenario where the diagnostic function cannot obtain airplane installation effects is considered. The installation effects in question is air intake pressure loss (pressure recovery), bleed flow and shaft power extraction. A framework is presented where the unknown installation effects are estimated based on available data through surrogate models, which is incorporated into the diagnostic framework. The method has been evaluated for a low-bypass turbofan with two different sensor suites. It has also been evaluated for two different diagnostic schemes, both determined and underdetermined. Results show that, compared to assuming a best-guess constant-bleed and shaft power, the proposed method reduce the RMS in health parameter estimation from 26% up to 80% for the selected health parameters. At the same time, the proposed method show the same degradation pattern as if the installation effects were known.

PERFORMANCE PREDICTION OF A 112M WAVE-PIERCING CATAMARAN

The prediction of power required to propel a high-speed catamaran involves the hydrodynamic interactions between the hull surface and the surrounding fluid that may be difficult to compute numerically. In this study model-scale experiments are used as a basis for comparison to full-scale sea trials data measured on a 112m Incat wave-piercing catamaran to predict the full-scale powering requirements from model-scale testing. By completing water jet shaft power measurements on an Incat vessel during sea trials, comparison of these results was made to model-scale test results to provide good correlation. The work demonstrates that the International Towing Tank Conference (ITTC) extrapolation techniques used provide a good basis for extrapolating the data from model-scale to full-scale to predict the power requirements for the full-scale catamaran vessel operating at high Froude Number with water jet propulsion. This provides a useful tool for future designers and researchers for determining the power requirements of a catamaran vessel through model tests.

Efficiency Scaling - Influence of Reynolds and Mach Number on Fan Performance

The efficiency, pressure ratio and shaft power of a fan depends on type, size, working medium and operating condition. For acceptance tests, a dissimilarity in Reynolds number, Mach number, relative roughness and relative blade tip clearance of the scaled model and prototype is unavoidable. Hence, the efficiency differs between model and prototype. This difference is quantified by scaling methods. This paper presents a validated and physics based, i. e. reliable scaling method for the efficiency, pressure ratio and shaft power of axial and centrifugal fans operating at subsonic conditions. The method is validated using test results gained on standardized test rigs for different fan types, sizes and operating conditions. For all scenarios the presented scaling method provides a much reduced scaling uncertainty compared to the reference method described in ISO 13348.

Gas Turbine Compressor Configuration Analysis for Production and Efficiency Optimization at PT Saka Indonesia Pangkah Ltd.

Gas Turbine Compressors are used by Saka Indonesia Pangkah Ltd. in upstream oil and gas facilities either to boost hydrocarbon products to downstream facilities or to lift liquid hydrocarbon as a common artificial method. As production rate declining leads to gas supply deficiency to the compressors, the operating point move to surge line away from the best efficiency point. Gas feed shortage affecting the compressor’s performance which contributed to head and flow capacity. This condition is then calculated and simulated using UNISIM Design Simulator to get optimum configuration results. The simulation was performed at the same gas turbine shaft power output of each compressor. Two cases of centrifugal compressors configuration with different functions and performance are studied. Due to process dynamic conditions, constraint parameter is considered as per desired operating point. This paper also analyses techno-economic aspects between individual and serial pipelines arrangement of the two compressors by evaluating operational data and design calculation. Subsequently, this study produces assessment observations associated with the compressor performance both in individual and serial configuration and eventually analyses the rate of fuel consumption in the gas turbines as the main driver. The case study shows serial arrangement between MPC-1 and GLC with same gas turbine shaft power as individual configuration can reduce fuel consumption up to 47 kg/hr. It saves as much as USD 7,569.96 per day at low demand and USD 7,569.96 at high-demand cases.

Universal programmable portable measurement device for diagnostics and monitoring of hydraulic and pneumatic equipment

The paper presents a new universal programmable portable measuring device (PMD) intended for the diagnostic and monitoring of hydraulic and pneumatic equipment. PMD offers a simple, complete, and efficient remote monitoring and diagnostic solution for hydraulic and pneumatic equipment. PMD is designed for measurement, recording, and processing of data as well as graphical visualization of registered results on a test stand or in the operating site of hydraulic and pneumatic equipment. PMD is designed to measure parameters used in servicing, repairing, monitoring, and diagnosing hydraulic and pneumatic equipment. Usually, fluidic characteristic quantities (pressure, flow rate, temperature), mechanical quantities (position, linear speed, rotational speed, force, torque, shaft power), and electrical quantities (voltage, current, power) is measured. PMD with WiFi communication is adopted to transfer measurement data via the Industry Internet of Things (IIoT) technology to remote online monitoring and diagnostic hydraulic and pneumatic equipment. Sensors, controllers, and other devices are connected to the computing gateway via their respective protocols.

Rack-Level Thermosyphon Cooling and Vapor-Compression Driven Heat Recovery: Compressor Model

This paper introduces a novel thermal management solution coupling in-rack cooling and heat recovery system. System-level modeling capabilities are the key to design and analyze thermal performance for different applications. In this study, a semi-empirical model for a hermetically sealed scroll compressor is developed and applied to different scroll geometries. The model parameters are tuned and validated such that the model is applicable to a variety of working fluids. The identified parameters are split into two groups: one group is dependent on the compressor geometry and independent of working fluid, whereas the other group is fluid dependent. By modifying the fluid-dependent parameters using the specific heat ratios of two refrigerants, the model shows promise in predicting the refrigerant mass flow rate, discharge temperature and compressor shaft power of a third refrigerant. Here, the approach has been applied using data for two refrigerants (R22 and R134a) to achieve predictions for a third refrigerant’s (R407c) mass flow rate, discharge temperature, and compressor shaft power, with normalized root mean square errors of 0.01, 0.04 and 0.020, respectively. The normalization is performed based on the minimum and maximum values of the measured variable data. The technique thus presented in this study can be used to accurately predict the primary variables of interest for a scroll compressor running on a given refrigerant for which data may be limited, enabling component-level design or analysis for different operating conditions and system requirements.

A Study On Adapted Similitude Modeling Method of Turboexpander with Different Gas Working Fluids

The study on similitude modeling method of turboexpander with different working fluids is not only the key technical means and necessary method for the research and development of turboexpander with special working fluids, but also an effective way to further expand the application scope of turboexpander. In this paper, a new similitude modeling method (NSMM), which is based on dimensional analysis, actual characteristics of real gas and seven similitude criteria, is proposed. On the basis of modeling criterion p4, the new similitude relationship of turboexpander with different gas working fluids is obtained based on rotational speed, inlet total temperature, specific heat ratio and gas constant. Aiming at NSMM, the similitude modeling performance of turboexpander with air, methane, CO2 and helium is verified by using Computational Fluid Dynamics method. The results show that the modeling effects on aerodynamic performance are well predicted in a wide range including the design point (expansion ratio 2.9~5.0), and the errors of the total-to-total isentropic efficiency, relative equivalent mass flow rate, relative equivalent shaft power are less than 0.74%, 1.94% and 1.69%, respectively. Methane and CO2 have the best modeling performance, their errors of efficiency, relative equivalent mass flow rate and relative equivalent shaft power are all less than 0.5%; Furthermore, the NSMM also has pinpoint accuracy with the prediction of internal flow field, which provides a good idea for further research on special working fluid turboexpander and an approach to expand the application scope of turboexpanders.

Manure Pulverizers and Applicators: A Review

Background: Manures (FYM, vermicompost, edible oil cakes etc.) are important resources which provide nutrients that could reduce bagged fertilizer costs and improves the crop growth and performance. A well-managed manure is a valuable resource in providing nutrients for crop production. As manure dries, nutrients not only get concentrated on a weight basis, but also on a volume basis due to structural changes. Compared to fresh manure, it is easier to handle and transport because of decreased volume and weight. Hence, it is necessary to pulverize the manure when it is applied to the land. Methods: Various research works previously carried out on manure pulverizers and applicators have been considered in the study to come up with an idea of developing a tractor powered manure pulverizer cum applicator. Studies concluded the importance of manure pulverization, effect of wind, angle of repose and coefficient of friction in the designing and development of manure dispensing equipment. Result: Manure pulverizer integrated with tractor PTO along with an applicator was designed and developed. The machine consists of KAU manure pulverizer, feed chute, blower, frame and hitch, gearbox and extension shaft. Power to the gearbox was drawn from the tractor PTO. Dried manure was continuously fed through the feeding chute and rotating blade helps in pulverizing the manure until it achieves a size smaller than the sieve. The pulverized manure reaches the blower unit by means of a chute and gets discharged through the flexible pipes. Maximum field capacity was noted at a traveling speed of 3.0 km h-1. A larger application rate of 1387.1 kg ha-1 for cow dung, 1624.4 kg ha-1 for goat faecal pellets and 1618.6 kg ha-1 for neem cake was noted at an engine rpm of 2500, forward speed of 2 km h-1 with a field capacity of 0.31 ha h-1.