bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid-Liquid Extraction (LLE) of Furfural Purification from Oil Palm Empty Bunch with Toluene Solvent
Authors: Utami Salsabila Posmaryana , Harahap Andre Fahriz Perdana , Darmawan Muhammad Arif , Ramadhan Muhammad Yusuf Arya , Gozan Misri
Published: June 2022

Oil Palm Empty Brunches (OPEB) as lignocellulose can be hydrolyzed into various chemical compounds with high selling value, such as furfural. Furfural purification by liquid-liquid extraction (LLE) produced higher furfural yield compared to other methods. The solvent must have a high solute capability to achieve the LLE process with the highest furfural yield. Toluene was chosen as a solvent because it shows high solubility in furfural extraction. The purpose of this research is to determine the optimum operating conditions for furfural LLE with toluene from the OPEB hydrolysate model. The variable in this research is stirring time (30, 60, 90 minutes), extraction stage (1x, 2x, 3x), and extraction temperature (25, 45, 65°C). Analysis of furfural content in the organic phase was carried out using HPLC. The Response Surface Methodology (RSM) determined the optimum furfural LLE condition in the Design-Expert software using the Box-Behnken model. This research can be used as a reference for obtaining the best furfural yield from OPEB hydrolysate using the LLE method with toluene.
Synthesis of Bio Hydrocarbon from Palm Olein through Pyrolysis at Various Temperature
Authors: Setyaningsih Dwi , Siagian Crisman Arianto , Muna Neli , Purwoko
Published: June 2022

The synthesis of biofuels through the pyrolysis of vegetable oil is studied as an alternative to the biodiesel process because it produces bio hydrocarbons that have similar properties to fossil fuels. This study uses palm olein as raw material reacted at gradually increasing temperatures ranging from 225, 250, 275, and 300°C, using zeolite as catalyst at atmosferic pressure. The volatiles compounds are condensed and collected according to the fraction and analyzed for density, viscosity, calorific value, moisture content and composition of volatile compounds using GC-MS. Palm olein as raw material had the characteristics of moisture content of 0.095% (w/w), viscosity of 41.25 mm2/s, calorific value of 39.93 MJ/kg and pour point of 20°C. The hydrocarbon fractions of various temperatures had a red to bright yellow color, liquid phase and only the 300°C fraction which had a solid fraction. The density was in the range of 0.8452 - 0.8527 g/cm3(40°C), viscosity of 3.0726 - 3.8137 mm2/s, moisture content of 0.0801 - 0.1878% (w/w) and pour point of 4 - 22 ° C. Density, viscosity and pour point from a temperature fraction of 225 – 275°C met national biodiesel standards. The composition of volatile compounds mainly consisted of n-decanoic acid, undecanoic acid, dodecanoic acid, 8-heptadecene, heptadecane, tetradecanoic acid, 2-heptadecanone, and n-hexadecanoic acid. The main volatile compounds were still in the form of fatty acids where n-hexadecanoic acid was the dominant compound (42.8 - 71.6%). In general, the characteristics and profiles of the volatile compounds of 225, 250 and 275°C fractions were similar and different from the 300°C fraction.
Production of Fuel pellet From Agricultural And Plantation Estate Crops Biomass
Authors: Alamsyah Rizal , Samid Dedy Darmawan , Heryani Susi , Siregar Nobel Christian
Published: June 2022

Biomass contains energy used as solid fuel so that biomass will have high added value. Directly combustion of biomass has caused environmental pollution problems. Agricultural and plant estate plantation biomass waste that is widely spread in Indonesia needs to be utilized. The research was aimed at designing and producing biomass pellets for a pilot-scale capacity of 200 kg/hour. The biomass used consisted of empty oil palm fruit bunches (OPEFB), oil palm shells (OPS), cocopeat, corn cobs, and sugar cane bagasse. Pellets are formed by pressing biomass powder with high pressure using a 10 hp pelletizer. The quality of pellets produced was tested based on the standard DIN 53731. The performance test of pelletizing machinery showed that such types of machinery could be produced for 150-200 kg/hour. The test results showed that almost all quality parameters of biomass pellet (moisture content, calorific value, ash content, density, length, and diameter) met the requirements. Synthetic gas produced from burning biomass pellets in the gasifier and stove is able to use for drying and heating for 80 minutes. Pelletizing can enhance the volumetric and calorific value, reduce the transport and storage costs, reduce the moisture content, and improve the handling characteristics of biomass.
The Potential of Energy Production and Greenhouse Gases Emission Reduction from Households Organic Waste in Bandar Lampung, Indonesia
Authors: Utami Wanda Gustina , Yogautami Radya , Yuliandari Puspita , Iryani Dewi Agustina , Hasanudin Udin
Published: June 2022

Households Organic Waste (HOW) is the type of waste dominantly found in the Bakung landfill, Bandar Lampung. It is because HOW from the settlements is only collected and transported to the landfill without any recycling treatment. A study was carried out to determine the potential of biogas generation and greenhouse gases (GHG) emission reduction related to the rate of generation waste, composition, and characteristics of HOW in Bandar Lampung city. The method for collecting sample and analysis procedure in this work was following into SNI 19-3964-1994. From the data results of sampling and measurement, it was known that the average HOW generation rate was 0.11 kg/person/day, which consists of 26.39% of vegetable scraps, 44.83% of fruit scraps, and 28.79% ripe food scraps. The Total Solids (TS) of HOW was 6.70%. Utilization of HOW to produce biogas was conducted through crushing the HOW in the crusher by adding water with ratio water, and HOW was 3:1. Based on estimation production data of HOW in 2020, it was estimated that Bandar Lampung city could produce about 1.40 million m3 of CH4/year, which is equivalent to 1.07 million kg of LPG. Meanwhile, converting HOW to produce biogas, it was estimated will reduce 21.09 million kg of CO2-eq/year of GHG emissions.
Utilization of rice husks as a fuel for gasification – A review
Authors: Fathurahman Reza , Surjosatyo Adi
Published: June 2022

Rice husks are widely known as a fuel for electricity generation through gasification technology. Rice husks are abundant in agricultural countries, especially in South and Southeast Asia. Although it is useful, if it is not handled properly, rice husks can become dangerous waste. Abandoning them at large amounts of wastes in fields can damage soil and water contaminated, increase the emission of methane due to its natural decomposition, and produces rainwater leachates. Rice husks are produced from 20% of the weight of rice produced. The content of rice husk is cellulose (50%), lignin (25-30%), silica (15-20%), and moisture content (10-15%). Rice husks have low bulk density by the range of 90-150 kg/m3. From studies obtained equivalent ratio (ER) is range 0.15-0.35, gasifier temperature was conducted at 600-900°C. This paper presents a review of studies conducted on rice husk gasification. Recent research has been reviewed, and key findings are highlighted based on each result of syngas produced. Syngas produced from gasification has a low heating value of 1373.18 kcal/Nm3 – 2603 kcal/Nm3. Syngas compositions are CO, CO2, CH4, and H2. Rice husks syngas are used as a fuel to the internal combustion engine (ICE) as the prime mover to produce electricity.
An Investigation on Gasification Conversion of Municipal Solid Waste Using Fixed Bed Downdraft: Study Case of Final Processing Site TPA Putri Cempo Surakarta
Authors: Sonjaya Abeth Novria , Surjosatyo Adi
Published: June 2022

The municipal solid waste (MSW) gasifier is one of the promising technologies to fulfill the energy demand of TPA Putri Cempo Surakarta. Municipal solid waste gasification is a chemical process that converts solid Municipal solid waste into useful, convenient gaseous fuel. According to the government program in presidential regulation number 35 of 2018, the acceleration of waste processing development into electric energy based on environmentally friendly technology needs to be developed. One of the technologies to convert waste into renewable energy is to use thermochemical processes of gasification. The aim of this paper is to investigate the conversion of municipal solid waste gasification (MSW) using a fixed bed downdraft gasifier by circulating the mass balance of municipal solid waste (MSW) to be converted into syngas with a variation of air-fuel ratio (AFR) of 0.1 to 1.0 and gasifier temperature at 500 – 1000°C. The result showed that the fixed bed downdraft gasifier produced syngas with the composition of CO (24.78%), CO2 (18.65%), H2 (15.6%), and CH4 (4.06%), with an AFR of 0.3 at a gasification temperature of 600°C.both.
Effect of granular matrix on functional flora in EBPR system
Authors: Qi He Zhe
Published: June 2022

Enhanced biological phosphorus removal (EBPR) is a very mature phosphorus removal technology, but there is still a problem of unstable treatment effect in the operation of actual wastewater treatment plants, so the study on the effect of phosphorus removal performance still needs to be further studied. Because there are a lot of granular matrix in municipal wastewater, it occupies an important proportion in the total Chemical Oxygen Demand (COD) of municipal wastewater, and the fluctuation of granular matrix concentration is also related to the instability of phosphorus removal effect. Therefore, it is of practical guiding significance to further explore the influence of granular matrix on the functional bacteria community of phosphorus removal in the enhanced biological phosphorus removal system. The acetic acid was used as a carbon source to enrich and cultivate phosphorus accumulating bacteria. After the enrichment and the system was stable, soluble starch was added into the water to study the effects of granular matrix on phosphorus removal performance and functional bacteria community in EBPR system. The results showed that acetic acid was beneficial to the proliferation of phosphorus-accumulating bacteria in the enrichment stage, and the phosphate removal rate of the system could reach more than 99%. After the system is stabilized, granular matrix with different concentrations is added to the system in three stages, and the phosphate removal rate of the system gradually decreases. With the increasing of granular matrix concentration in the influent, the phosphorus removal performance of sludge decreased gradually, the maximum phosphorus release rate and maximum phosphorus uptake rate of sludge decreased, and the acetic acid utilization rate ΔP/ΔHAc value also decreased. Fluorescence in situ hybridization was used to measure the changes of functional bacteria in activated sludge under different conditions. With the increase of the concentration of soluble starch, the proportion of PAOs gradually decreased, and the proportion of GAOs gradually increased. Granular matrix exists in the internal of floc sludge and cannot be utilized by PAOs, which results in inhibition of the growth of PAOs and weakened activity. This indicates that the higher concentration of granular matrix will lead to a decrease in the proportion of PAOs in EBPR system, and then lead to a decrease in the phosphorus removal activity of activated sludge, and ultimately reduce the phosphorus removal effect of EBPR system.
Climate variability and change in Tibetan Plateau within a warming climate
Authors: Duan Sirui
Published: June 2022

Global warming has become a subject of concern with an increasing number of natural disasters under the excessive emission of greenhouse gasses, influencing many sectors of environment, society, and economy. Likewise, the climate of the Tibetan Plateau region (known as “the roof of the world”) is closely related to global warming. Yet, the variation and prediction of climate in Tibetan Plateau remain unresolved. The purpose of this research is to diagnose and forecast the climate change in Tibetan Plateau in China within the context of global warming based on surface temperature and precipitation data. Specifically, the results suggest that global warming closely affects the rising trend of the average temperature of the Tibetan Plateau, while the average precipitation of the Tibetan Plateau is also producing an increasing trend with the increase of temperature. In order to prevent the environmental ecosystem of the Tibetan Plateau from being destroyed by severe climate change under the future influence of global warming, the government should regulate greenhouse gas emissions to ensure that global warming does not worsen.
Applied microbiology and chemical engineering in full solidliquid recovery of food waste
Authors: Wang Zhipu , Zhao Yiran , Liu Kai
Published: June 2022

Food waste (FW) has been a major challenge globally in the environment, economy and society. It is estimated that about 8–10% of global greenhouse gas emissions are linked to FW. As FW exhibits characteristics of high organic matter content (mainly proteins, fats and organic acids), high moisture content and low calorific value, aerobic composting is more suitable than conventional treatments of solid waste (e.g. incineration and landfill) for disposing of FW while recovering renewable energy from it in the form of fertiliser. In contrast, the struvite technology allows for the recovery of nitrogen (N) resources from the dewatering liquor. Therefore, this report investigates the recovery pathways and effectiveness of resource recycling in solid-liquid FW based on aerobic composting and struvite crystallisation. The main findings suggest that aerobic composting is an effective pathway for the recycling of FW while struvite crystallisation could recycle N resources from dewatering liquor of FW.
A study on the investment in the collection and transportation system for domestic waste in rural areas
Authors: Yao Xiaoqiang , Hou Meifang
Published: June 2022

This paper analyzed the domestic waste collection and transportation projects in rural areas as derived from the project management database of the National PPP Integrated Information Platform, obtained the investment intensity of waste collection and transportation system and other relevant indicators, explored the investment level of domestic waste collection and transportation system in the rural areas of China, and also proposed the initial investment intensity and the attention gradient of investment planning. of domestic waste collection and transportation system.
Preparation of porous activated carbon with ultra-high specific surface area and its adsorption performance for specific organic pollutants in industrial wastewater
Authors: Yao Tingjun , Zhong Dan , Ai Wei , Li Zhiyang , Han Guang , Hao Wenming , Yang Lei
Published: June 2022

Porous activated carbon particles (GAC-1) with ultra-high specific surface area were prepared from starch by hydrothermal carbonization and high temperature activation. The porous structure and surface morphology of GAC-1 were characterized by N2 adsorption desorption isotherm and SEM. Compared with the commercially available activated carbon with the same particle size, the porous GAC-1 with ultra-high specific surface area shows better adsorption performance for CODCr, pyrazole and chloroform in wastewater. The results show that when the amount of activated carbon in the fixed bed is 160 g/L, the removal rate of CODCr, pyrazole and chloroform is 97.3%, 96.1% and 98.0%, respectively. The effluent meets the reuse requirements of the plant (CODCr ≤ 1500 mg/L). Finally, the activated carbon was regenerated five times by simple thermal regeneration method, and the COD removal rate could still reach 87.9%.
Effects of Slotted Impeller Configurations on the Hydraulic Performance of Double-Suction Pump
Authors: Yoon Jong-Woong , Kang Hyun Su , Kim Youn-Jea
Published: June 2022

A double-suction centrifugal pump is widely used in various industrial fields due to its stable and durable operability. There are many studies to improve pump performance, but in most cases changes in blade angle and thickness have been considered. In this paper, the optimal design was performed to improve the hydraulic performance of the double-suction centrifugal pump by applying slotted blade geometry. The shape of the slotted impeller is defined by angle, clearance, and location. A range of values, for each parameter, were selected and used in the design of experiments (DOE). An optimized space-filling design sampling technique (OSFD) was used to select 25 points for optimization through the response surface method. Response surfaces effectively analyze the correlation between the design variables and performance variables. The objective of the optimization is to increase efficiency. The numerical results of the optimized model are graphically depicted and compared with the coefficients using the ANSYS CFX. Through comparison with the results from the reference model, it is shown that the optimized slotted impeller decreased the turbulence kinetic energy and stabilized the flow.
High flexibility in Francis turbine operation and design philosophy: A review
Authors: Kverno J O , Iliev I , Dahlhaug O G
Published: June 2022

This paper examines and discusses how various operation schemes and design philosophies can prolong the expected lifetime of a hydro turbine subjected to many start-stop cycles and high ramping rates. With the proliferation of renewable and non-dispatchable energy sources in Europe, a higher demand for flexible operation is put on the rest of the system. Given the short response time of hydro power, there is a huge potential for the Norwegian power sector to act as a stabiliser for the rest of mainland Europe. With a more flexible operation however, the turbines will experience a higher load variation which can lead to premature fatigue and failure of existing turbines. This research reviews the current startup and ramping schemes, as well as design aspects, which might affect and reduce the mechanical stresses experienced by the hydro turbine.
Use of 3D Printing technology for developing novel procedure to manufacture runner of Francis Turbine
Authors: Kafle Abishek , Shrestha Pratisthit Lal , Silwal Raman , Thapa Bhola , Ghimire Amul , Chitrakar Sailesh
Published: June 2022

Turbine having complex profiles has always been a challenge to the manufacturers. With possible errors while manufacturing and surface finishing, it is nearly impossible attaining the same profile of blades or buckets as suggested by the hydraulic design. Specifically in the case of Nepal the manufacturing of Francis turbine runners has been a challenge due to its complex profile and lack of state-of-the-art manufacturing facilities in the Nepalese metal manufacturing industries. Many attempts have been made in the past to manufacture these runners with the available resources. However, the developed turbines have been of smaller size and dimensions and the process used for fabrication have been limited to these small runners. So, for fabrication of the Francis turbine runners a new process has been developed. The process makes use of a rapid prototyping technique called additive manufacturing. The developed method has made the manufacturers easier to manufacture the runners of complex profiles and larger size. The steps from modifications of the cad model to 3D printing and workshop fabrication has been discussed in this paper.
Experimental Analysis of a Simplified Francis Turbine
Authors: Ghimire A , Sapkota P , Kayastha A , Thapa B S , Choi Y D , Lee Y H
Published: June 2022

Introduction of Francis turbine in Nepalese micro hydropower project has been considered to uplift the turbine manufacturing ability of the local turbine manufacturers, along with the rejuvenation of the micro hydro sector in Nepal. The Francis turbine used in this study was designed for a Micro hydropower plant in Nepal. The design has been simplified in order to facilitate the local manufacturing of the turbine. The locally manufactured Francis turbine has been tested at Turbine Testing Laboratory under variable rotational speed and discharge. The performance of the Francis turbine has been measured at different operating conditions. The CFD analysis performed on the turbine has also been compared to the results obtained from the experiments. The results of pressure fluctuations, during a transient phenomenon, increase in speed of the runner under no load conditions (runaway), has also been studied under different operating conditions.
Numerical investigation of Cavitation in Francis Turbine
Authors: Twayna Ranjeet , Manandhar Ram , Singh Bikash , Dahal Dadiram , Kayastha Atmaram , Thapa Biraj Singh
Published: June 2022

Cavitation is one of the major challenges in the Himalayan rivers of Nepal that cause damage and degradation of the performance of hydraulic turbine components. Numerical analysis has been performed to investigate the cavitation effect in the Francis turbine. For detection of cavitation, the SST turbulence model using Rayleigh plesset equation has been used in ANSYS-CFX. The turbine is investigated for three different operating conditions i.e. part load, BEP and full load under cavitation and without cavitation. The results are shown based on efficiency, pressure fluctuation, vortex rope and vapor volume fraction. It has been observed that changes in efficiency and pressure distribution are found to be minimal between cavitation and without cavitation conditions at rated discharge and head. Under part load condition, turbine efficiency loss and vapor bubbles formation at the leading edge of the runner blade is found to be maximum.
Study on Setting Elevation of Double-Suction Centrifugal Pump Based on Cavitation Characteristics
Authors: Qi Dunzhe , Yao Rao , Zhang Haichen , Shen Yubin , Song Xijie , Wang Zhengwei
Published: June 2022

Setting elevation is an important factor affecting the safe operation of pumps, and the empirical calculation method in engineering cannot fully reflect the cavitation characteristics. In this paper, numerical simulation of cavitation in double-suction centrifugal pump with clearances is carried out. The cavitation characteristics under different flow rates was analyzed based on the setting elevation from the empirical method. It was found that there was cavitation inception under both large flow rate and small flow rate. The cavitation characteristics of the pump with different net positive suction head available (NPSHa) is analyzed. It is found that there is no obvious change in the pump characteristics from cavitation inception to critical cavitation, but after the point of the critical cavitation is reached, a large number of cavities plug the blade passage, and the efficiency decreases rapidly. The results show that in engineer although critical net positive suction head (NPSHc) is considered and the safety margin is increased, it is difficult to ensure that there is no cavitation inception happened in the pump. The cavitation characteristics analyzed by numerical simulation in this paper can provide guidance for the selection of suitable setting elevation.
Numerical analysis of the effect of slit shape on the performance and cavitation instability of liquid rocket inducer
Authors: Kowata A , Kawasaki S , Iga Y
Published: June 2022

In this study, a three-dimensional numerical analysis of unsteady cavitation in various inducers with slits of different widths and depths was performed to find the optimal slit shape to suppress the cavitation instabilities. The numerical analysis was performed using ANSYS CFX19.0. The analysis results were evaluated about possibility of suppression of cavitation instabilities and head performance. As a result, the optimum slit shape was suggested. It was also suggested that it is important to top the cavity growth near the slit for to the suppression of the cavity asymmetry.
Credibility of Rotating Disc Apparatus for investigating sediment erosion in guide vanes of Francis turbines
Authors: Aryal Shekhar , Chitrakar Sailesh , Shrestha Rajendra , Jha Ajay kumar
Published: June 2022

Estimation of sediment erosion in hydraulic turbines is limited by the broad range of dependent parameters, such as characteristics of sediment, base materials and flow conditions. Some mathematical models have been proposed in the past literatures and some of them has been incorporated in a CFD tool for predicting the erosion together with the flow conditions. Rotating Disc Apparatus is a simplified experimental setup that was initially developed targeting on erosion studies in Francis turbines. However, the closeness of the results obtained from this apparatus with the actual turbine remains uncertain. This paper focuses on investigating the flow phenomena inside the region of guide vanes using RDA and comparing with the actual turbine. A reference case of Jhimruk hydropower plant has been taken in this study, which has been scaled down with a factor of 1.6 from its original size. The numerical fluid domain consists of four rotating blades distributed around the disc uniformly. The pressure distribution around the guide vanes inside RDA along with development of the tip-vortices have been compared with the results from the past research works. The experiment consists of a qualitative analysis of the wear pattern, which has been compared with the results of the CFD. It is found that flow field around guide vanes inside RDA matches closely with that of the real turbine. The stagnation point and development of the pressure and suction sides are similar to the actual guide vanes, which makes the apparatus suitable for investigating the erosion after including the sediment particles. However, more investigations might be needed for using the same apparatus for the runner blades, or guide vanes at different operating conditions.
Influence factors of clearance leakage flowrate and clearance hydraulic axial force of pump-turbine
Authors: Hou X X , Cheng Y G , Hu D L , Xue S , Wang B , Zhang X X , Wang X , Ding J H , Liu D M
Published: June 2022

The clearance flow of pump-turbine has significant influence on hydraulic forces of the runner, which is related to safety of the unit. To clarify the influence factors, clearance flowrate and clearance hydraulic axial force of a prototype pump-turbine were analyzed by 3D CFD simulations. The results show that the rotational speed, and the smallest radial sizes of clearance inlet, outlet, and the seal ring sizes are the determinant factors for clearance leakage flowrate, while the rotational speed and the radial size at clearance inlet are the major factors for clearance axial force. The rotational speed of rotating surfaces mainly affects the strength of rotating shear flow, while geometric sizes mainly affect the hydraulic loss of leakage flow. By assuming that the clearance region as several ring pipes, we obtained the simplified calculation formulas for estimating clearance leakage flowrate and clearance axial force. The flowrate can be expressed as a function of the water head difference across the clearance region, the rotational speed, and the sizes of clearance inlet, outlet and sealing ring, while the clearance axial force is a function of the inlet pressure and the square of both radius and rotational speed. The formula calculations agree with the numerical simulations well. This paper can provide a reference for runner clearance size design.
Numerical Investigation on Hydraulic Performance at Low Flow Rates of a Mixed-flow Pump with Impeller Inlet Diameter Effects
Authors: Kim Y I , Yang H M , Lee K Y , Choi Y S
Published: June 2022

A mixed-flow pump has a characteristic in which the pressure (P) decreases as the flow rate (Q) increases on the performance curve. Hence, the Q-P curve generally has a negative slope, which has been understood as an ideal and stable case. However, a complex recirculating flow may occur due to the increase in incidence angle at the low flow rates compared to the design flow rate. This phenomenon accompanies noise and vibration along with the deterioration of performance and causes a positive slope in the form of a saddle on the performance curve. In this study, the effect of the impeller inlet (eye) diameter of a mixed-flow pump on the saddle characteristics was confirmed through numerical simulation. The focus was on the internal flow field and performance of a pump, which could be solved with the steady-state analysis. Here, the impeller inlet diameter was adjusted with the leading edge (LE) vertex on the shroud line of the meridional plane. The blade angle was adjusted accordingly to maintain the previously optimized degree of the incidence angle. From this novel design method, the saddle characteristics were significantly improved. The performance in the saddle range was directly related to the recirculating flow near the shroud. The numerical results were validated with the experimental tests.
Numerical investigation of the non-condensable gas effect on predicting the cavitation performance of a centrifugal pump
Authors: Cao Lei , Mingming Liu , Zhengwei Wang , Yiyang Zhang
Published: June 2022

Improving the prediction accuracy of cavitation performance of pumps is a research hotspot. The non-condensable gas effect has been included in some existing cavitation models. However, the amount of the non-condensable gas in water still needs discussing since it will affect the vaporization process. In this paper, Zwart-Gerber-Belamri model was used to calculate the cavitation performance of a three-blade centrifugal pump with water temperature of 10 °C and a corresponding cavitation experiment was carried out to verify the numerical model. Numerical results respectively with five volume fractions of the non-condensable gas were analyzed. Compared to the recommended default value, the head drop curve obtained with a much lower volume fraction of the non-condensable gas agrees better with the experimental result. Comparison and analysis of the cavitation patterns as well as the flow field indicates that the default volume fraction of the non-condensable gas which was proposed at 25 °C overestimates the interphase mass transfer rate at 10 °C Reasonably setting the volume fraction of non-condensable gas in the cavitation model will achieve more accurate cavitation pattern, and then the head drop curve of pump can be predicted more precisely.
Study on Measurement of Penstock Head Loss for Hydropower Station with Multiple Units Per Penstock
Authors: Zhou Y , Tuo Y , Cao D F , Li C L , Wu D J
Published: June 2022

For a hydropower station with multiple units per penstock, how to get the head loss of penstock has usually been a difficult problem, which the core issue is that it is hard to obtain the flow of each branch pipe. For power stations that have installed flow measurement devices for all units, or have undergone absolute turbine efficiency tests, the head measurement is relatively simple, but if the flow measuring device is not installed for each unit in advance, the head loss measurement will be difficult. This paper proposes an optimized measurement method performed in a hydropower station in Pakistan, which is to arrange an ultrasonic flowmeter on the main penstock, and then use the Winter-Kennedy method and flow rate measured by Ultrasonic flow meter to calibrate the Winter-Kennedy coefficients of unit one by one. Finally, by running three units at the same time and adjusting them with the same flow rate, the total loss of the penstock is calculated. At the same time, the flow rate measured by the Winter-Kennedy coefficient and that measured by the ultrasonic method has been checked and compared. The result proves that the accuracy of the result is high, and the result has a good consistency, which can fully meet the requirements of penstock head loss calculation and evaluation. The method has a certain practical value and can be referred to by other power station which has similar measurement.
Unsteady Simulation of the Internal Flow in a Tubular Pump Considering Tip-Leakage Flow
Authors: Li P , Jin F , Tao R , Zhang F , Xiao R
Published: June 2022

Tip-leakage vortex is a commonly-seen phenomenon in tubular pump runners because there will be always gap between blade and pump shroud. In the operation process, the tip-leakage vortex is unstably varying. Pressure in the vortex core is relatively low and may induce cavitation in extreme conditions. The operation stability will be strongly impacted. As an effective tool, computational fluid dynamics (CFD) can be used in predicting the vortical flow in pumps. In this study, unsteady CFD simulation is conducted with the visualization of tip-leakage vortex using the Q criterion. The design-load condition is mainly studied. The temporal characters, their frequency domain features and their spatial distributions are fully analysed. This study will help understanding the tip-leakage vortical flow in the tubular pump and enhance the operation stability of low-head pumping stations.
Numerical simulation of the runner blade channel vortex in Francis turbine
Authors: Cheng Huan , Zhou Lingjiu , Liang Quanwei , Zhou Peijian , Wu Zhongjing , Liu Demin , Wang Zhaoning , Li Guoyuan
Published: June 2022

The runner blade channel vortex could induce cavitation erosion, noise and vibration, when Francis turbines operate at part load condition. It's usually difficult to simulate the channel vortex exactly in runner passage, this paper attempts to predict the runner channel vortex in some operating conditions with different discharge and speed factors.The results show that the structure and intensity of runner channel vortex are various between the vortex incipient and development line. The velocity distribution indicates that there is a relationship between the channel vortex and backflow region near the hub with different specific discharge factors, while the flow incident angle has a distinct variation with different specific speed factors. Furthermore, this work enables the researchers to understand the flow field and carry out optimization design in runner hydraulic research.
Dynamic Experimental Review of Hydraulic Turbine Stay Vane Strengthen for Baihetan Hydropower Station Left Bank
Authors: Xiaohong Fang , Haijun Li , Chunjian Cao , Jie Fang , Jinjie Deng
Published: June 2022

Stay ring is the foundation-bearing components of Francis turbine-generator unit and an important part of the flow components. It should not only have enough strength and rigidity, but also excellent hydraulic performance. As the unit capacity of Baihetan Hydropower Station reaches 1000MW, the priority should be on safety. After completing the turbine model acceptance test of Baihetan Hydropower Station Left Bank, it was found that the local stress at the tail of stay vanes was too high in the re-check analysis of the rigidity and strength of the stay ring. In order to ensure the stay ring has sufficient safety margin, the stay vane should be strengthened in design. After stay vane strengthened, the rigidity and strength of the stay ring are improved obviously. In this paper, the strengthen design, stiffness and strength analysis and model verification of turbine stay vane for Baihetan Hydropower Station Left Bank are analyzed and explained.
Study of the phase resonance phenomenon in Francis turbine
Authors: Lv Yue , Wang Zhengwei , Zhou Lingjiu
Published: June 2022

In hydraulic machinery, the phenomenon of rotor-stator interaction will produce periodic pressure waves in the stationary cascade. These pressure waves have the same phase, and will spread and superimpose in the volute. When the pressure waves propagate and superpose, the pressure pulsation with large amplitude will be formed. This phenomenon is called phase resonance, which will threaten the safe and stable operation of the machinery. Therefore, it is necessary to study the rotor-stator interference phenomenon and analyze the risk of phase resonance. In this paper, a high head Francis turbine with phase resonance in engineering is analyzed, which is also verified by the existing theoretical analysis. The phase resonance in the turbine is analyzed by using one-dimensional hydro acoustic model and three-dimensional compressible flow CFD simulation method, and the results are consistent with the actual engineering phenomenon. In order to study the measures to improve the phase resonance phenomenon, this paper carries out the simulation calculation from changing the rotation speed, wave speed and guide vane-runner blade number combination. The results show that adjusting the above parameters can reduce the amplitude of large pressure pulsation caused by the phase resonance in different degrees, and changing the number combination of guide vanes and runner blades is the most effective and feasible measure.
Vibration Analysis of 3D printed runner with CNN for using deep learning in hydropower for condition monitoring
Authors: Silwal Raman , Kafle Abishek , Shrestha Prajwal Sapkota Pratisthit Lal , Dahlhaug Dr. Ole Gunnar , Thapa Dr. Bhola
Published: June 2022

Convolutional Neural Networks are deep learning algorithms that are typically used for the classification of images. A black and white image can be represented as the number of rows and columns along with values of intensity for each of components of these rows and columns. Vibration measured with the help of accelerometer can be used to create an image like data. These data can be used for machine learning applications with the help of deep learning. In deep learning techniques, features do not have to be extracted from the data set. The CNN network can generate a feature-like set which can be further classified with a fully connected neural network to give out the probability over the predefined class. The neural networks model is trained with a data set created in laboratory conditions to monitor the unfractured and single blade fracture condition operation state. The paper deals with showing the proof of concept that CNN algorithms can be applied for conditional monitoring of runner blades. The paper mainly focuses on demonstrating that deep learning algorithms can be used as analysis tools for hydropower runners by applying these techniques in scaled versions of 3D printed runners.
Head-Cover vibration investigation of a Prototype Reversible Pump-Turbine Unit during Start-up in Pump mode. Part I: Fluid dynamic analysis
Authors: Yang Haixia , He Qilian , Bi Huili , Huang Xingxing , Yang Mengqi , Zou Mingde , Wang Zhengwei
Published: June 2022

Reversible pump-turbine units of pumped storage power stations can generate power in turbine mode and store electric energy in pump mode for load balancing of the electric power grid. During the start-up transient process in pump mode of a reversible pump-turbine, the flow pattern and the pressure distribution in the flow channel change dramatically with the increasing opening angle of guide vanes. The unsteady pressure of the flow passing channel can cause severe vibration on the head-cover, bottom ring, and other stationary structures around the impeller. In this paper, a coupled 1D/3D co-simulation approach is developed to investigate the pressure distribution characteristics of the flow field during the start-up transient process in pump mode for a large prototype reversible pump-turbine unit. The entire model of flow channel from spiral casing to draft tube is constructed and the flow characteristics of key fluid fields such as spiral casing, stay vanes, guide vanes, impeller, and draft tube are analyzed. The simulation results show that under the condition of minimum guide vane opening the flow is insufficient and vortices occur on the impeller blades. The pressure distribution results of the flow channel from 3D fluid dynamic analysis during the start-up transient process in pump mode are exported as boundary conditions for the subsequent fluid-structure coupling analysis of the head-cover vibration investigation.
Effect of fish swimming on the stability of flow fields inside the pipeline
Authors: Fang D , Huang Z , Zhang J , Hu Z
Published: June 2022

Hydraulic machinery and various pipeline systems will commonly be infiltrated by many aquatic creatures, and the aquatic community causes important impacts on the flow field, fluid stability inside the pipeline, and the performance of the hydraulic machinery. In this paper, the research about three-dimensional numerical simulation of fish swimming inside a pipeline is conducted, and lattice Boltzmann method is used to complete the flow field solution, where an immersed boundary method based on multi-direct forcing scheme is implemented to achieve the fluid-solid coupling. The fish swimming will be realized by using a time-dependent harmonic oscillation combined with surface vertices. The analysis of the velocity, flow field and vorticity distribution at different moments of fish swimming reveals that the fish passing through the pipeline causes a significant influence on the internal flow field, and the stability of the fluid inside the pipeline. The research in this paper provides referential significance to the operations of hydraulic machinery and pipeline systems in environments containing aquatic community.
Advanced ICT solutions in a distance vocational education and training in the field of robotics
Authors: Pilat Zbigniew , Arapi Polyxeni , Pappas Nikos , Omieljanowicz Miroslaw , Prokopiuk Norbert , Tamre Mart
Published: June 2022

Automation and robotization (A&R) is often the main driving force behind the development of advanced manufacturing, including the transformation of the company towards the Industry 4.0 model. Effective implementation and effective use of A&R solutions is possible only if the company has good prepared and educated employees. It applies to all levels, from the direct operation of machines and processes, through mid-level technical staff, to the management level. Nowadays, education of young staff, as well as training of those currently employed, requires the implementation of new solutions and methods of Vocational Education and Training (VET). They should ensure not only a high professional level, but also meet the challenges facing VET today: attractiveness of education for students, especially young ones, universal accessibility regardless of the place of residence, internationalization. The paper, presenting results of the MILAN project, shows that addressing those problems can largely be facilitated by the use of modern, advanced ICT solutions.
Investigation of the resistance, durability and abrasion of printed elements applied to sports equipment
Authors: Sidorov A , Iljin I
Published: June 2022

The work investigated the durability of the labelling of sports equipment made of composite materials. Professional hockey sticks were taken for research. Research has been done on hockey stick wear for different players: centre and winger and defender. In addition, a study was made of hockey sticks for left-handers and right-handers. In the study of the wear of printed elements, sports equipment of various lengths was used. Contact research was carried out during training and competition. The study of the number of contacts was carried out on the basis of video recordings of trainings and games of the teams “Energija” - ElektrÄnai (Lithuania) and the national team of the Belarusian Republic. The study carried out showed that the hockey stick wear of the centre striker and the winger during the competition and training is similar. During the competition, the hockey sticks of the centre strikers are most often in contact. It was found that the difference between contacts during training and playing depends on the intensity of the game, penalty time and strategy. When conducting a study of the wear of the printed elements applied to the hockey stick, depending on the position of the player, it was found that the wear of the sticks of the winger and the defender is the same, but that of the centre striker is different. When conducting a study of hockey stick wear depending on its length, the following conclusion was made: the taller the player, the longer his hockey stick and the maximum contact area. Research has shown that hockey stick wear is not affected by how the player holds the hockey stick, i.e. whether he is left-handed or right-handed. To study the abrasion of elements using the UGRA method, an original stand was created. With the help of this stand, studies of the abrasion of printed elements were carried out. Based on the study, it was concluded that the abrasion of printed elements most often occurs at the moment of contact of the objects of research, both with each other and with objects on the playing field. As a result, the printed elements split, peel off and become less noticeable, in addition, the name of the manufacturer's company is worn out and the hockey stick loses the player's personal identification data printed on the hockey stick. Recommendations are given on the peculiarities of printing and the location of printed elements on sports equipment.
Empirical analysis of piezoelectric stacks composed of plates with different parameters and excited with different frequencies
Authors: Harazin J , Wróbel A
Published: June 2022

Piezoelectric materials offer an ability to exchange energy between electrical and mechanical systems with fair ease, by using the simple and inverse piezoelectric effect. Piezoelectric transceivers, sensors, microphones, actuators, or active acoustic noise cancellation devices are some of many applications for piezoelectric materials. Due to the natural ability of the material to convert electricity and mechanical strain, solutions based on piezoelectric materials are often compact and allow applications on micro scales. One of the forms of piezoelectric actuation involves the use of piezoelectric stacks. The stack is composed of multiple piezoelectric plates layered by thin dielectric sheets, with electrodes attached along the sides. The main aim of piezoelectric stacks is the increase in maximum displacement by multiplying the number of piezoelectric plates that make up the stack. Stacks are composed of plates with the same material properties and the same dimensions. This study aims to investigate the idea of composing piezoelectric stacks of plates that have separate control circuits inducing different carrier frequencies or plates with differing properties and dimensions, in search for new applications for piezoelectric stacks. The main point of interest is the investigation of the ability to use piezoelectric stacks to generate complex vibration spectrums composed of multiple frequencies, resulting from the use of different piezoelectric plates in the stack or different carrier frequencies that stimulate each plate. To achieve this, a stack composed of two piezoelectric plates, each controlled by its own circuit, will be measured by a laser vibrometer, to check the complexity of the output vibration pattern.