Debt cash flow is a finance term describing a firm's non-equity cash flows. Theoretically, adding the discounted debt cash flow to the discounted flows to equity (also known as equity Cash Flows) will give the firm's enterprise value, the valuation obtained by calculating the discounted cash flow.
Discounted cash flow is often referred to by its initials DCF, which are consequently not commonly used for debt cash flow.
References
Debt cash flow Wikipedia(Text) CC BY-SA