A Numerical and Experimental Study of the Time Averaged and Transient Flow Downstream of a Butterfly Valve

This research took the DN50 butterfly valve as the research object and studied the flow situation of butterfly valves with different shafts. The resistance characteristics, flow state, characteristics, and flow instability of butterfly valves with different structures were studied by experiments and numerical simulations. Research shows that the edge of the valve disc occurs flow separation, and the drag of the valve disc fluctuates non-periodically with time. Under different opening degrees, the velocity distribution downstream of the valve varies, and the effect of the shaft on the velocity fluctuation is different. Finally, the unstable region of flow downstream of the valve is determined. This study provides a reference for the use and optimization of butterfly valves.

Soft Sensor of Heating Extraction Steam Flow Rate Based on Frequency Complementary Information Fusion for CHP Plant

Heating extraction steam (HEXTR) flow rate is the key parameter to determine the heat load of a combined heat and power (CHP) plant and the safe operation area of the steam turbine of CHP plant. Due to the difficulty of direct measurement, a soft measurement method of this flow rate is proposed. First, three calculation methods based on different principles are given: the Flügel formula of the steam turbine method, the butterfly valve flow characteristics method, and the improvement of heat balance characteristic of the turbine method. Then, a soft-sensing method through frequency complementary information fusion is proposed to combine the advantages of the three methods. The specific fusion algorithm uses Flügel formula of the turbine as a static model, the heat balance characteristic of the turbine to correct the coefficient in the model, and the butterfly valve characteristic to realize dynamic compensation. Finally, the proposed soft sensor is applied in the monitoring system of a typical 330 MW CHP plant. The actual operating data shows that the relative static measurement error of the soft sensor is less than 1% and the dynamic response is as fast as power load change.

MENGHITUNG BERAT BANDUL UNTUK MENGGERAKKAN BUTTERFLY VALVE (UV-7209) DI SEA WATER INTAKE DALAM MENCEGAH BACK PRESSURE PADA POMPA (G-7201) PADA KONDISI BLACKOUT

Air laut disuplai langsung dari lautan lepas menggunakan media pompa jenis submersible yang pada bagian discharge memliki tekanan 5,57 kg/cm2 dengan debit 11.600 m3/h melalui pipa 48” menuju pipa 66” dalam distribusinya ke berbagai unit. Dengan kapasitas tersebut, digunakan sebuah alat pengaman sistem distribusi, yang berguna untuk dapat menahan aliran balik dari sistem menuju discharge pompa pada kondisi listrik mati (blackout). Sebuah valve dengan menggunakan flange seberat 700 kg dan actuator berupa couter weight dengan massa 933,334 kg sebagai pemutus aliran mampu menahan aliran balik dengan daya 5621,564 hd, kecepatan 2,134 m/s dan tekanan 5,57 kg/cm2. Pada kondisi blackout actuator akan jatuh kebawah yang menimbulkan daya sebesar 20,774 hp untuk menutup 90% dan 20,517 hp untuk menutup penuh. Dari hasil daya tersebut maka valve akan membutuhkan waktu menutup 11,696 s pada 90% dan 14,349 s pada posisi full close. Dengan waktu yang diperoleh maka penggunaan valve masih layak digunakan.Keyword : Air laut, blackout, counter weight, massa, daya.