Advancing Suction Performance in Hydrocarbon Liquids

Author(s):  
Kevin A. Kaupert ◽  
Keijun Kamio

Details are presented on design investigations to advance the suction performance of inducers combined with centrifugal impellers for pumping liquid hydrocarbons such as liquefied natural gas (LNG). In particular minimizing the NPSHr3 is emphasized over the entire flow range. Design advances are made with the combined efforts of computational fluid dynamics, analytical methods, and test results. In particular the focus here is on inducer flow incidence and resulting blade loading by examining the NPSHr3 performance of the variable pitch and constant pitch helical style inducers for use over the full flow rate range taken as 35% to 130% of the pump BEP. Results indicate the combined centrifugal impeller with a variable pitch inducer tends to have lower NPSHr3 at BEP and below the pump BEP flow rate, but the constant pitch inducer can have superior performance near the pump maximum flow rate.

Author(s):  
Shunya Takao ◽  
Kentarou Hayashi ◽  
Masahiro Miyabe

Abstract In order to improve suction performance, centrifugal pumps with an inducer are used for rocket pumps, liquid gas transport such as LNG, and general-purpose pumps. Since a higher suction performance than conventional pump is required, a splitter blade that consists of a long blade and a short blade is sometimes adopted. However, the design becomes more difficult due to the increased number of parameters. The stable operation over a wide flow rate range are required in the general-purpose pumps. Therefore it is necessary to design them so that unstable flow phenomena such as surges do not occur. However, the design method to avoid them is not well understood yet. In this study, we focused on the splitter blade impeller in a general-purpose low-speed centrifugal pump with an inducer. Six parameters such as leading edge position and trailing edge position of the short blade for both hub-side and tip-side were set as design ones. A multi-objective optimization method using a commercial software was applied to improve suction performance while maintaining high efficiency. Then obtained optimal shape were analyzed by CFD calculation and extracted the feature. Furthermore, optimized impellers were manufactured and confirmed the performance over a wide flow rate range by experiments. In addition, a optimizing design method that improves pump performance at lower cost was studied.


Author(s):  
A. Chaudhuri ◽  
N. M. Wereley

Substantial research has been conducted in the development of hybrid hydraulic actuators driven by various smart materials. The basic operation of these actuators involves high frequency bidirectional length change of an active material stack (rod) which is converted to unidirectional motion of a hydraulic fluid by a set of active or passive valves. In this paper, we present the design and experimental test results of a compact hybrid actuation driven by the electrostrictive material PMN. The active material was actuated at different frequencies, with variations in the applied voltage and fluid bias pressure to study their effects on performance. The tests were carried out under no-load conditions and also with external weights to find the maximum flow rate and blocked force respectively. The maximum actuator velocity was calculated to be 330 mm/s and the corresponding flow rate was 42.5 cc/s. The blocked force of the actuator was found to be 63 N and the maximum power output was 8 W. Dynamic tests were also conducted to find the PMN stack response without any fluid loads. Results of the experiments are presented and compared with simulation data.


Author(s):  
Takaki Igoshi ◽  
Yuki Uchinono ◽  
Emosi Koroitamana ◽  
Koichi Ishizaka ◽  
Satoshi Watanabe ◽  
...  

The installation of inducer upstream of main impeller is an effective method to improve the suction performance of turbopump. However, various types of cavitation instabilities are known to occur even at the designed flow rate as well as in the partial flow rate range. In the present study, we focus on the leading edge sweep of inducer and investigate its effect on the suction performance as well as on the onset of cavitation surge phenomenon. Flow measurements including casing wall pressure measurements, high-speed video observations, and limiting streamline observations are carried out, and discussions will be made based on those results about the influence of backward leading edge sweep on the internal flow of the inducer as well as its relation to the cavitation performance.


Author(s):  
Masahiro Ishida ◽  
Daisaku Sakaguchi ◽  
Hironobu Ueki

In order to obtain a wider operating range in a centrifugal impeller with inducer, the effect of the pre-whirl induced by the inlet recirculation flow on the flow incidence and the impeller characteristics were analyzed numerically and compared with the experimental results. In order to control the swirl intensity of the recirculation flow, guide vanes were installed circumferentially in the annular bypass of the ring groove arrangement, and the setting angle of the guide vane was changed. The fundamental concept for surge suppression is to achieve the flow incidence less than or close to the critical one. A too large-positive flow incidence can be reduced by increasing the recirculation flow rate determined by the pressure difference between the two ring groove positions, on the other hand, a higher pressure rise in the inducer can be obtained at the flow incidence close to the critical one by suppressing the pre-whirl induced by the recirculation flow. It is clearly shown that the better impeller characteristics and the large recirculation flow rate can be achieved by giving a suitable setting angle of the guide vane. The unstable flow rate range of the tested impeller was reduced by about 53% almost without deterioration of the impeller efficiency in the whole flow rate range.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3212
Author(s):  
Kiattisak Sakulphan ◽  
Erik Bohez

A micro hydropower plant of the run-of-river type is considered to be the most cost-effective investment in developing counties. This paper presents a novel methodology to improve flow estimation, without using the flow direction curve (FDC) method, to determine the turbine type and size to operate consistently. A higher precision is obtained through the use of seasonal flow occurrence data, irrigation variability, and fitting the best probability distribution function (PDF) using flow data. Flow data are grouped in classes based on the flow rate range. This method will need a larger dataset but it is reduced to a tractable amount by using the PDF. In the first part of the algorithm, the average flow of each range is used to select the turbine type. The second part of the algorithm determines the optimal size of the turbine type in a more accurate way, based on minimum and maximum flow rates in each class range instead of the average flow rate. A newly developed micro hydropower plant was installed and used for validation at Baan Khun Pae, Chiang Mai Province. It was found, over four years of observation from 2014–2018, that the plant capacity factor was 82%.


Author(s):  
K. Hayashi ◽  
S. Konno ◽  
M. Hayakawa ◽  
Y. Kawata

Suction performance is one of the most important characteristics of the industrial pump to keep the pump capability against the cavitation under the low suction pressure condition. Inducers have been developed to improve the suction performance of pumps. They are used for rocket turbo pumps and recently for many industrial applications. It is one of the competitiveness of the industrial pumps to downsize the scale with higher rotational speed by adopting inducer. The authors had proved that pump with splitter impeller with inducer can further improve the suction performance. The splitter impeller was specially designed to be resistant to the cavitation choke. The other very important requirement for the pump against cavitation is that it does not occur cavitation surge. The cavitation surge arises at the partial flow rate of the pump. In contrast to this the suction performance become better at the partial flow rate. So the precise compromise is necessary to satisfy these requirements. This paper presents the experimental and CFD results to improve and optimize the suction performance without generating cavitation surge. The many design and combination of splitter impeller and inducer are tested to get the better performance. The test results of pumps with different inlet flow coefficient are compared not only suction performance but also the onset of cavitation surge.


2018 ◽  
Vol 0 (2) ◽  
pp. 34-45
Author(s):  
Орест Євгенович Середюк ◽  
Тетяна Володимирівна Лютенко ◽  
Анна Григорівна Винничук

2020 ◽  
Vol 19 (2) ◽  
pp. 64-68
Author(s):  
Mrinmoy Biswas ◽  
Sudip Das Gupta ◽  
Mohammed Mizanur Rahman ◽  
Sharif Mohammad Wasimuddin

Objective: To assess the success of BMG urethroplasty in long segment anterior urethral stricture. Method: From January 2014 to December 2015, twenty male patients with long anterior segment urethral stricture were managed by BMG urethroplasty. After voiding trial they were followed up at 3 month with Uroflowmetry, RGU & MCU and PVR measurement by USG. Patients were further followed up with Uroflowmetry and PVR at 6 months interval.Successful outcome was defined as normal voiding with a maximum flow rate >15ml /sec and PVR<50 ml with consideration of maximum one attempt of OIU after catheter removal. Results: Mean stricture length was 5.2 cm (range 3-9 cm) and mean follow-up was 15.55 months (range 6-23 months). Only two patients developed stricture at proximal anastomotic site during follow-up. One of them voided normally after single attempt of OIU. Other one required second attempt of OIU and was considered as failure (5%). Conclusion: BMG urethroplasty is a simple technique with good surgical outcome. Bangladesh Journal of Urology, Vol. 19, No. 2, July 2016 p.64-68


Author(s):  
Yuchuan Zhu ◽  
Chang Liu ◽  
Yunze Song ◽  
Long Chen ◽  
Yulei Jiang ◽  
...  

In this paper, an electro-hydrostatic actuator driven by dual axial-mounted magnetostrictive material rods-based pumps (MMPs) with a new type of active rectification valve is designed in the current study. Based on flow distribution of the active rectification valve and driving energy provided by two MMPs, the actuator can output continuous and bidirectional displacement. By establishing a mathematical model of the actuating system, using simulation techniques, the change rule of hydraulic cylinder’s motion state caused by different driving signals are studied and analyzed. Test equipment platform is constructed in the laboratory to test the output characteristics and confirm the feasibility of the new concept. The experimental results indicate that the maximum flow rate can reach approximately 2.7 L·min−1, while the operating frequency is 180 Hz.


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