PHÂN TÍCH TỔN THẤT THỦY LỰC CỤC BỘ TRONG DÒNG CHẢY TẦNG TẠI CÁC KẾT CẤU PHỨC TẠP

0 Người đánh giá. Xếp hạng trung bình 0

Tác giả: Trường Sang Hà, Mạnh Hùng Nguyễn

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Journal of Science and Technique, 2023

Mô tả vật lý: tr.5

Bộ sưu tập: Báo, Tạp chí

ID: 347992

Thêm vào giỏ Liên kết toàn văn

Minor head loss occurs in most hydraulic equipment because the flow is affected by a shape change. Head loss analysis is essential in designing and fabricating hydraulic equipment and systems. In the general case, the evaluation of head losses is challenging and usually done by experimental methods. Recently, the calculation has been more convenient using the computational fluid dynamics (CFD) method. This article employs the finite element method (FEM) to evaluate the local hydraulic losses in complex geometries discretized by unstructured mesh. The method is applied to the laminar flow of Newtonian fluid. First, the code is validated by comparing the numerical solution with experimental data and previous numerical results. The code is then employed to simulate different problems, including a complex geometry that mimics the control valve in hydraulic systems. Simultaneously, the minor loss coefficient is calculated for different Re numbers. From the results, the minor loss coefficient is large for low Re, and can be up to 700 for Re = 10 of complicated geometry. For a high Re, the minor loss coefficient is rapidly decreased and close to the value of a turbulent model.Tổn thất thủy lực cục bộ xảy ra trong hầu hết các thiết bị thủy lực do dòng chảy bị ảnh hưởng bởi việc thay đổi hình dạng. Việc phân tích tổn thất thủy lực có ý nghĩa quan trọng trong thiết kế và chế tạo các thiết bị và hệ thống thủy lực. Trong trường hợp tổng quát, việc phân tích này rất khó khăn và thường được thực hiện theo phương pháp thực nghiệm. Gần đây, việc tính toán thuận tiện hơn nhờ phương pháp CFD. Trong bài báo này, phương pháp phần tử hữu hạn được sử dụng để tính toán tổn thất thủy lực cục bộ trong các kết cấu phức tạp dựa trên lưới không cấu trúc. Phương pháp này được thực hiện cho dòng chảy tầng chất lỏng Newton. Trước tiên, thuật toán được kiểm chứng qua việc so sánh lời giải số với các dữ liệu thực nghiệm và kết quả số trước đó. Sau đó, thuật toán này được sử dụng để mô phỏng các bài toán khác nhau, bao gồm cả dạng hình học phức tạp tương tự van điều khiển trong các hệ thống thủy lực. Đồng thời, hệ số hiệu chỉnh động năng được tính theo các số Re khác nhau. Dựa vào kết quả phân tích, hệ số tổn thất cục bộ đạt giá trị lớn đối với số Re thấp, có thể lên đến 700 đối với Re = 10 đối với hình học phức tạp. Đối với số Re cao, hệ số tổn thất cục bộ được giảm xuống nhanh và gần tiệm cận với giá trị của dòng chảy rối.

1. Đọc trực tuyến

1. Đọc trực tuyến

Tạo bộ sưu tập với mã QR