Study on Axial Clearance Size and Leakage of Canned Motor Pump under Axial Force Self-Balance State

Canned motor pump is widely used in chemical industry. Due to the particularity of its application, it is necessary to ensure that the medium does not leak completely. If the axial force of impeller is too large, it will directly affect the performance of canned motor pump. Therefore, the floating impeller could be used in the pump to balance the axial force. In this paper, the relationship between axial clearance and leakage rate at the key part of canned motor pump is studied by means of numerical calculation and experimental verification. It is found that the fitting curve is highly consistent with the calculated value, which provided a good theoretical basis for further study of axial clearance control axial force and experimental axial force self-balance. In addition, the leakage rate increases with the increase of axial clearance. The static pressure in the axial clearance first increases and then decreases with the decrease of radius, and the maximum static pressure value is about 10.5% ∼ 15.8% near the clearance inlet. This study is of great significance to the theoretical research on the self-balance state of axial force of impeller.

PENGGUNAAN DATA MINING DALAM EKSTENSIFIKASI PENELITIAN ULANG

ABSTRACT Due to increasing volume of international trade, effect on increasing customs document, Customs play a role so that trade flows run without obstacles, this causes inspection of imported goods to be less than optimal, but on the other hand Customs are required to collect state revenues optimally. This study tries to solve this problem from the post-clearance control side with re-examination by construct an analytical data model to predict the suitable classification. This study uses data on the Notification of Imported Goods during 2020 at the Regional Office of DJBC XXX which using a sample of goods that has similarities but has the potential to be misclassified. This study uses the Cross-industry Standard Process for Data Mining (CRISP-DM) model and the Rapid Miner Studio 9.9.2 application. Based on the model formed, the prediction results obtained according to the appropriate classification according to data mining. It also found the factors that most impact to goods classification, the most impact is the Importer status, whereas the least impact is the goods lane. ABSTRAK: Seiring dengan volume perdagangan internasional yang semakin tinggi, jumlah dokumen kepabeanan yang harus diperiksa juga mengalami peningkatan. Hal ini menghambat peran Bea dan Cukai sebagai fasilitator perdagangan yang menyebabkan pemeriksaan barang impor kurang optimal. Di sisi lain, Bea dan Cukai dituntut untuk menghimpun penerimaan negara secara optimum. Penelitian ini mencoba untuk menyelesaikan permasalahan tersebut pada tahap post clearance dengan penelitian ulang, yaitu dengan membangun model data analitik untuk memprediksi klasifikasi barang yang diberitahukan oleh importir sudah sesuai atau belum. Penelitian ini menggunakan data Pemberitahuan Impor Barang selama tahun 2020 pada Kanwil DJBC XXX yang sampel data barangnya memiliki kemiripan tetapi berpotensi salah klasifikasi. Penelitian ini menggunakan model Cross-industry Standard Process for Data Mining (CRISP-DM) dan aplikasi Rapid Miner Studio 9.9.2. Berdasarkan permodelan yang dibentuk, didapatkan hasil prediksi klasifikasi yang sesuai menurut data mining. Didapat pula faktor yang paling memengaruhi kebenaran pemberitahuan klasifikasi barang impor, yaitu status importir, sedangkan yang paling tidak berpengaruh adalah jalur pengeluaran barang impor. Kata Kunci: Penelitian Ulang, Data Analitik, Penerimaan Negara, Klasifikasi Barang

Effect of Jet-to-Jet Distance and Pipe Position On Flow and Heat Transfer Features of Active Clearance Control Systems

The goal of the present work is to investigate the effect of supply pipe position on the heat transfer features of various active clearance control (ACC) geometries, characterized by different jet-to-jet distances. All geometries present 0.8 mm circular impingement holes arranged in a single row. The jets generated by such holes cool a flat target surface, which is replicated by a metal plate in the experimental setup. Measurements are performed using the steady-state technique, obtained by heating up the target plate thanks to an electrically heated Inconel foil applied on the side of the target opposite to the jets. Temperature is also measured on this side by means of an IR camera. Heat transfer is then evaluated thanks to a custom designed finite difference procedure, capable of solving the inverse conduction problem on the target plate. The effect of pipe positioning is studied in terms of pipe-to-target distance (from 3 to 11 jet diameters) and pipe orientation (i.e. rotation around its axis, from 0° to 40° with respect to target normal direction), while the investigated jet Reynolds numbers range from 6000 to 10000. The obtained results reveal that heat transfer is maximized for a given pipe-to-target distance, dependent on both jet-to-jet distance and target surface extension. Pipe rotation also affects the cooling features in a non-monotonic way, suggesting the existence of different flow regimes related to jet inclination.

Effect of Jet-to-Jet Distance and Pipe Position on Flow and Heat Transfer Features of Active Clearance Control Systems

The goal of the present work is to investigate the effect of supply pipe position on the heat transfer features of various active clearance control (ACC) geometries, characterized by different jet-to-jet distances. All geometries present 0.8 mm circular impingement holes arranged in a single row. The jets generated by such holes cool a flat target surface, which is replicated by a metal plate in the experimental setup. Measurements are performed using the steady-state technique, obtained by heating up the target plate thanks to an electrically heated Inconel foil applied on the side of the target opposite to the jets. Temperature is also measured on this side by means of an IR camera. Heat transfer is then evaluated thanks to a custom designed finite difference procedure, capable of solving the inverse conduction problem on the target plate. The effect of pipe positioning is studied in terms of pipe-to-target distance (from 3 to 11 jet diameters) and pipe orientation (i.e. rotation around its axis, from 0° to 40° with respect to target normal direction), while the investigated jet Reynolds numbers range from 6000 to 10000. The obtained results reveal that heat transfer is maximized for a given pipe-to-target distance, dependent on both jet-to-jet distance and target surface extension. Pipe rotation also affects the cooling features in a non-monotonic way, suggesting the existence of different flow regimes related to jet inclination.

A Comparison of Single-Entry and Multiple-Entry Casing Impingement Manifolds for Active Thermal Tip Clearance Control

In this paper, we compare using computational fluid dynamics the aero-thermal performance of two candidate casing manifolds for supplying an impingement-actuated active tip clearance control system for an aero-engine high-pressure turbine. The two geometries are (a) single-entry: an annular manifold fed at one circumferential location; (b) multiple-entry: a casing manifold split into four annular sectors, with each sector supplied separately from an annular ring main. Both the single-entry and multiple-entry systems analysed in this paper are idealised versions of active clearance control systems in current production engines. Aero-thermal performance is quantitatively assessed on the basis of the heat transfer coefficient distribution, driving temperature difference for heat transfer between the jet and casing wall and total pressure loss within the high-pressure turbine active clearance control system. We predict that the mean heat transfer coefficient (defined with respect to the inlet temperature and local wall temperature) of the single-entry active clearance control system is 77% greater than the multiple-entry system, primarily because the coolant in the multiple-entry case picks up approximately 40 K of temperature from the ring main walls, and secondarily because the average jet Reynolds number of impingement holes in the single-entry system is 1.2 times greater than in the multiple-entry system. The multiple-entry system exhibits many local hot and cold spots, depending on the position of the transfer boxes, while the single-entry case has a more predictable aero-thermal field across the system. The multiple-entry feed system uses an average of 20% of the total available pressure drop, while the feed system for the single-entry geometry uses only 2% of the total available pressure drop. From the aero-thermal results of this computational study, and in consideration of holistic aero-engine design factors, we conclude that a single-entry system is closer to an optimal solution than a multiple-entry system.

A Comparison of Single-Entry and Multiple-Entry Casing Impingement Manifolds for Active Thermal Tip Clearance Control

In this paper we compare using computational fluid dynamics the aerothermal performance of two candidate casing manifolds for supplying an impingement-actuated active tip clearance control system for an aero-engine high-pressure turbine. The two geometries are (a) single-entry: an annular manifold fed at one circumferential location; (b) multiple-entry: a casing manifold split into four annular sectors, each sector supplied separately from an annular ring main. Both the single-entry and multiple-entry systems analysed in this paper are idealised version of active clearance control systems in current production engines. Aerothermal performance is quantitatively assessed on the basis of the heat transfer coefficient distribution, driving temperature difference for heat transfer between the jet and casing wall, and total pressure loss within the high-pressure turbine active clearance control system. We predict that the mean heat transfer coefficient (defined with respect to the inlet temperature and local wall temperature) of the single-entry active clearance control system is 77% greater than the multiple-entry system; primarily because the coolant in the multiple-entry case picks up approximately 40 K of temperature from the ring main walls, and secondarily because the average jet Reynolds number of impingement holes in the single entry system is 1.2 times greater than in the multiple entry system. The multiple-entry system exhibits many local hot and cold spots, depending on the position of the transfer boxes, while the single-entry case has a more predictable aerothermal field across the system. The multiple-entry feed system uses an average of 20% of the total available pressure drop, while the feed system for the single-entry geometry uses only 2% of the total available pressure drop. From the aerothermal results of this computational study, and in consideration of holistic aero-engine design factors, we conclude that a single-entry system is closer to an optimal solution than a multiple-entry system.

A Comparison of Single-Entry and Multiple-Entry Casing Impingement Manifolds for Active Thermal Tip Clearance Control

In this paper, we investigate the aerothermal performance of active clearance control (ACC) methods that use impingement as a means of enhancing heat transfer. We describe a numerical approach to compare the aerothermal performance of two circumferential impingement manifold supply designs that vary in the number of entry points to the manifold channel. For a 180°-sector, the first design has a single entry point, while the second has two. Both the single-entry and multiple-entry systems analysed in this paper are idealised version of ACC systems in current production engines. Aerothermal performance is quantitatively assessed on the basis of the HTC distribution, driving temperature difference for heat transfer between the jet and casing wall, and total pressure loss within the HPT ACC system. We conclude key advantages and disadvantages of each system based on the impact on engine efficiency, response time, ease of optimisation and implications for weight, cost and complexity of the design.